Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Jim Cathey via Mercedes]

> In the case of the trailer the manufacturer jumped on the bandwagon and 
> probably sold it as a benefit to UHaul -- "it will be cheaper in the long 
> run!"

Bingo!  And, I bet it isn't.

-- Jim


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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Floyd Thursby via Mercedes]

Yeah I hate the retrofit LED headlights (and I guess even the new ones 
on trucks and cars these days that are blinding).  The goobers around 
here like the eye-burners in their squatted pickups.  It's cook I 
guess.  I can't really see the point but there it is.  I have not 
noticed other lights blinking or whatever.


In the case of the trailer the manufacturer jumped on the bandwagon and 
probably sold it as a benefit to UHaul -- "it will be cheaper in the 
long run!"


I was looking for a replacement headlight unit for the S550 (W221), the 
newer ("facelift") ones seem to have LED strips in them and wouldn't 
work in the car, but some guys retrofit the controllers or nannies or 
something into their older cars. Seems like too much work but whatever.  
The new LED lighting all seems like a one-unit thing, and yeah, will 
have to be replaced as a unit if they will even be available in the 
future.  More throwaway disposable "energy saving" when a $2 bulb could 
save a car from being junked because the parts are either NLA or too 
expensive for a 10 or 15yo car.


Even this S550 headlight was like $650 new from a stealer, not LED 
stuff.  And it is just cheap plastic with some ballasts and bulbs and 
whatnot, certainly nothing in there particularly exotic but there you go.


--FT

On 8/14/22 12:52 PM, Jim Cathey wrote:

I agree, replace like with like, but in this case UHaul put them in a trailer 
and that caused the issue with the older vehicle.  I guess some sort of 
resistor or whatever would do the job but it would kinda defeat the LED aspect.

And what aspect is that?  Blindingly-bright epilepsy-inducing blinking?  
Pointless energy saving
on a fuel-burning vehicle?  It's certainly not cost-saving!  Incandescent bulbs 
are cheaper.


Probably the power supplies in them as they tend to get dim or blink before finally 
failing.  The LED emitters themselves are probably still OK but can't get any electrons 
to turn into photons.  So much for "lifetime" bulbs.

LED lamps are not 'forever' devices.  The LEDs themselves degrade with time,
as do the phosphors used in white lamps.  Heat kills/degrades the LEDs, too.
There's no incentive for a fly-by-night manufacturer to make a device that works
for very long.  They particularly like to shortcut the thermal design aspects, 
resulting
in devices that fail prematurely.

Back to the trailer.  I believe that the _system_ cost of LEDs is higher.  Yes, 
an
incandescent installation needs periodic bulb replacement, but said replacements
are cheap, and usually easy to do.  Restoring 100% as-new functionality when 
done.
LED systems are not as cheap, 'need no servicing', and may be 
difficult/expensive/impossible
to service when the LED array inevitably does exhibit problems.  But, that'll 
be long after
the warrantee is over, and so it's not the manufacturer's problem.  It's yours.

Ever been behind a truck/trailer that has LED taillights that aren't at 100%?  
Flickering?
Spastic blinking?  Some LED emitters clearly out?  I have.  You have to go to 
the dealer/mfr
to fix that, not FLAPS.  Bet it's not cheap!  (Might not even be possible.)

-- Jim


--
--FT
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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[OK Don via Mercedes]

Yup, the underlying technology does not want 120v AC. It has to be
converted, and that adds complexity, cost, and lower efficiency.

On Sun, Aug 14, 2022 at 11:42 AM Allan Streib via Mercedes <
mercedes@okiebenz.com> wrote:

> On Sun, Aug 14, 2022, at 12:36, Floyd Thursby via Mercedes wrote:
>
> > I need to replace a load of LED spot bulbs I put in my kitchen 8-10yr
> > ago, most of them have burned out.  Probably the power supplies in them
> > as they tend to get dim or blink before finally failing.  The LED
> > emitters themselves are probably still OK but can't get any electrons to
> > turn into photons.  So much for "lifetime" bulbs.
>
> It has been my experience that none of the CFL or LED bulbs I've been
> forced to buy over the last 5-10 years deliver a real-world service life
> any longer than incandescents. They may use less electricity, but they also
> cost 10x as much.
>
> ___
> http://www.okiebenz.com
>
> To search list archives http://www.okiebenz.com/archive/
>
> To Unsubscribe or change delivery options go to:
> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
>
>

-- 
OK Don

"Quality of life is inversely proportional to the amount of clothing you
are wearing."

"Whenever you find yourself on the side of the majority, it is time to
pause and reflect." Mark Twain

“Basic research is what I’m doing when I don’t know what I am doing.”  Wernher
Von Braun
2013 F150, 18 mpg
2017 Subaru Legacy, 30 mpg
1957 C182A, 12 mpg - but at 150 mph!
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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Jim Cathey via Mercedes]

> I agree, replace like with like, but in this case UHaul put them in a trailer 
> and that caused the issue with the older vehicle.  I guess some sort of 
> resistor or whatever would do the job but it would kinda defeat the LED 
> aspect.

And what aspect is that?  Blindingly-bright epilepsy-inducing blinking?  
Pointless energy saving
on a fuel-burning vehicle?  It's certainly not cost-saving!  Incandescent bulbs 
are cheaper.

> Probably the power supplies in them as they tend to get dim or blink before 
> finally failing.  The LED emitters themselves are probably still OK but can't 
> get any electrons to turn into photons.  So much for "lifetime" bulbs.

LED lamps are not 'forever' devices.  The LEDs themselves degrade with time,
as do the phosphors used in white lamps.  Heat kills/degrades the LEDs, too.
There's no incentive for a fly-by-night manufacturer to make a device that works
for very long.  They particularly like to shortcut the thermal design aspects, 
resulting
in devices that fail prematurely.

Back to the trailer.  I believe that the _system_ cost of LEDs is higher.  Yes, 
an
incandescent installation needs periodic bulb replacement, but said replacements
are cheap, and usually easy to do.  Restoring 100% as-new functionality when 
done.
LED systems are not as cheap, 'need no servicing', and may be 
difficult/expensive/impossible
to service when the LED array inevitably does exhibit problems.  But, that'll 
be long after
the warrantee is over, and so it's not the manufacturer's problem.  It's yours.

Ever been behind a truck/trailer that has LED taillights that aren't at 100%?  
Flickering?
Spastic blinking?  Some LED emitters clearly out?  I have.  You have to go to 
the dealer/mfr
to fix that, not FLAPS.  Bet it's not cheap!  (Might not even be possible.)

-- Jim


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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Allan Streib via Mercedes]

On Sun, Aug 14, 2022, at 12:36, Floyd Thursby via Mercedes wrote:

> I need to replace a load of LED spot bulbs I put in my kitchen 8-10yr 
> ago, most of them have burned out.  Probably the power supplies in them 
> as they tend to get dim or blink before finally failing.  The LED 
> emitters themselves are probably still OK but can't get any electrons to 
> turn into photons.  So much for "lifetime" bulbs.

It has been my experience that none of the CFL or LED bulbs I've been forced to 
buy over the last 5-10 years deliver a real-world service life any longer than 
incandescents. They may use less electricity, but they also cost 10x as much.

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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Floyd Thursby via Mercedes]

I agree, replace like with like, but in this case UHaul put them in a 
trailer and that caused the issue with the older vehicle.  I guess some 
sort of resistor or whatever would do the job but it would kinda defeat 
the LED aspect.


I need to replace a load of LED spot bulbs I put in my kitchen 8-10yr 
ago, most of them have burned out.  Probably the power supplies in them 
as they tend to get dim or blink before finally failing.  The LED 
emitters themselves are probably still OK but can't get any electrons to 
turn into photons.  So much for "lifetime" bulbs.


--FT

On 8/14/22 10:53 AM, Jim Cathey wrote:

I wonder why there are no adaptations from the [LED] bulb manufacturers for 
backwards compatibility.

Physics.  If you MUST draw X current in order to make the bulb nanny happy,
it has to go somewhere, and that somewhere is heat.  Which is diametrically
opposed to long life for the LED itself.

Just use incandescent bulbs.  They last a long time and are cheap, and easy
to replace when/if necessary.

-- Jim


--
--FT
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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Jim Cathey via Mercedes]

> I wonder why there are no adaptations from the [LED] bulb manufacturers for 
> backwards compatibility. 

Physics.  If you MUST draw X current in order to make the bulb nanny happy,
it has to go somewhere, and that somewhere is heat.  Which is diametrically
opposed to long life for the LED itself.

Just use incandescent bulbs.  They last a long time and are cheap, and easy
to replace when/if necessary.

-- Jim


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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Kaleb Striplin via Mercedes]

Interesting 

Sent from my iPhone

> On Aug 13, 2022, at 5:17 PM, dan penoff.com via Mercedes 
>  wrote:
> 
> The real irony here is that the only place I’ve been able to find some sort 
> of adapter that converts from the 7 pin to 4 pin connector while also 
> accommodating LED trailer lights is at UHaul:
> 
> https://www.uhaul.com/MovingSupplies/Wiring-Lights/Adapters/LED-Light-Trailer-Module/?id=4089#
> 
> Even more ironic is that I found a broken link to this in the Banz Whirled 
> W164 forum. I’m swinging by my UHaul place tomorrow to get the one they have 
> in stock so I’ve got it on hand for the next time.
> 
> -D
> 
> On Aug 13, 2022, at 5:54 PM, Buggered Benzmail via Mercedes 
> mailto:mercedes@okiebenz.com>> wrote:
> 
> Good work!  You learned something with all that sweat and effort!
> 
> I think my CL has some LED replacement bulbs in the headlights. They work 
> fine but I get a whole bunch of warning messages on the instrument cluster. 
> Might be some in the taillights as well. I haven’t chased them down yet since 
> everything works but the nannies are Not Happy.
> 
> I guess newer cars have LEDs so the new replacements will work straightaway 
> but I wonder why there are no adaptations from the bulb manufacturers for 
> backwards compatibility.
> 
> --FT
> Sent from iFōn
> 
> On Aug 13, 2022, at 4:57 PM, dan penoff.com via Mercedes 
> mailto:mercedes@okiebenz.com>> wrote:
> 
> Kudos to Jim for confirming the pull up voltage theory!
> 
> I believe there has been a comedy of errors that led to this situation:
> 
> 1.) The voltage at the 7 pin socket is a “pull up” voltage from the SAM and 
> won’t carry any current to speak of.
> 
> 2.) This voltage, while minimal, was enough to light the LEDs in the adapter 
> socket, which would explain why they were lit for the turn signals when the 
> signals weren’t on.
> 
> 3.) The UHaul trailer, despite what the lot guy told me, almost certainly had 
> LED lights.
> 
> 4.) The circuitry in the SAM has “lights out” functionality much like it does 
> for any other light on the body. This means it wouldn’t have played nice with 
> LEDs in the circuit unless there was a load resistor somewhere.
> 
> How did I confirm?
> 
> A tried and true and quite antiquated approach - an 1157 bulb as a test 
> light. When connected to the appropriate terminal on the 7 pin socket, would 
> light up and perform as expected for turn signal, brake light or running 
> lights.
> 
> So I burned maybe 90 minutes and five pounds of sweat chasing this down, but 
> now I have a better understanding of the system and discovered the location 
> of a number of different components on the car. And I got a full diagnostic 
> scan on it as well, showing almost 100% check marks, which is always nice.
> 
> I finished my time up with a good Martha’ing on the interior with the shop 
> vac, and even found a little bit of cruft in the cowl vents I had missed that 
> has now been vacuumed out.
> 
> Lesson learned. I need to find an adapter that will allow the use of LEDs in 
> the trailer harness. Time to play inside for the rest of the day and enjoy 
> the AC.
> 
> -D
> 
> On Aug 13, 2022, at 4:10 PM, Kaleb Striplin via Mercedes 
> mailto:mercedes@okiebenz.com>> wrote:
> 
> The u haul trailer we rented a while back was all LED. Everyone I have seen 
> for a long time has been. Even with that it worked fine with our GL. I’m 
> wondering if someone installed the resistors or whatever is needed on mine to 
> make it work.
> 
> Sent from my iPhone
> 
> On Aug 13, 2022, at 2:40 PM, dan penoff.com via Mercedes 
> mailto:mercedes@okiebenz.com>> wrote:
> 
> Thanks for the insight, Jim, I was wondering this as well since the SAM 
> drives it directly. However, when it was plugged into a “real” trailer we 
> still got nothing.
> 
> I’ve got an 1157 lamp with some leads soldered to it - I’m going to try that 
> on each terminal and see what happens.
> 
> Everything else has checked out. Now I’m wondering if the UHaul trailer *did* 
> have LED lamps, as these do not work with this system for the same reason as 
> above. I asked the UHaul guys if the trailer lamps were LEDs and they said 
> no. Hmm. That would also explain why the diagnostic LEDs were lit on the 
> adapter - it would only take a a few mA to drive them.
> 
> More as I know it.
> 
> -D
> 
> On Aug 13, 2022, at 3:07 PM, Jim Cathey 
> mailto:jim.cathey...@gmail.com>> wrote:
> 
> And there is still power to all terminals at the 7 pin socket (except for 
> trailer brake and ground.)
> 
> Power?  Or +12V measured with a multi-megohm input impedance meter?
> (Zero current, essentially.)  Chances are it's got a pullup system, looking 
> for
> the load of bulbs to draw signals to ground so that the car can do lamp-out
> checking, and trailer-plugged-in checking, etc.
> 
> -- Jim
> 
> 
> ___
> http://www.okiebenz.com
> 
> To search list archives 

Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[dan penoff.com via Mercedes]

The real irony here is that the only place I’ve been able to find some sort of 
adapter that converts from the 7 pin to 4 pin connector while also 
accommodating LED trailer lights is at UHaul:

https://www.uhaul.com/MovingSupplies/Wiring-Lights/Adapters/LED-Light-Trailer-Module/?id=4089#

Even more ironic is that I found a broken link to this in the Banz Whirled W164 
forum. I’m swinging by my UHaul place tomorrow to get the one they have in 
stock so I’ve got it on hand for the next time.

-D

On Aug 13, 2022, at 5:54 PM, Buggered Benzmail via Mercedes 
mailto:mercedes@okiebenz.com>> wrote:

Good work!  You learned something with all that sweat and effort!

I think my CL has some LED replacement bulbs in the headlights. They work fine 
but I get a whole bunch of warning messages on the instrument cluster. Might be 
some in the taillights as well. I haven’t chased them down yet since everything 
works but the nannies are Not Happy.

I guess newer cars have LEDs so the new replacements will work straightaway but 
I wonder why there are no adaptations from the bulb manufacturers for backwards 
compatibility.

--FT
Sent from iFōn

On Aug 13, 2022, at 4:57 PM, dan penoff.com via Mercedes 
mailto:mercedes@okiebenz.com>> wrote:

Kudos to Jim for confirming the pull up voltage theory!

I believe there has been a comedy of errors that led to this situation:

1.) The voltage at the 7 pin socket is a “pull up” voltage from the SAM and 
won’t carry any current to speak of.

2.) This voltage, while minimal, was enough to light the LEDs in the adapter 
socket, which would explain why they were lit for the turn signals when the 
signals weren’t on.

3.) The UHaul trailer, despite what the lot guy told me, almost certainly had 
LED lights.

4.) The circuitry in the SAM has “lights out” functionality much like it does 
for any other light on the body. This means it wouldn’t have played nice with 
LEDs in the circuit unless there was a load resistor somewhere.

How did I confirm?

A tried and true and quite antiquated approach - an 1157 bulb as a test light. 
When connected to the appropriate terminal on the 7 pin socket, would light up 
and perform as expected for turn signal, brake light or running lights.

So I burned maybe 90 minutes and five pounds of sweat chasing this down, but 
now I have a better understanding of the system and discovered the location of 
a number of different components on the car. And I got a full diagnostic scan 
on it as well, showing almost 100% check marks, which is always nice.

I finished my time up with a good Martha’ing on the interior with the shop vac, 
and even found a little bit of cruft in the cowl vents I had missed that has 
now been vacuumed out.

Lesson learned. I need to find an adapter that will allow the use of LEDs in 
the trailer harness. Time to play inside for the rest of the day and enjoy the 
AC.

-D

On Aug 13, 2022, at 4:10 PM, Kaleb Striplin via Mercedes 
mailto:mercedes@okiebenz.com>> wrote:

The u haul trailer we rented a while back was all LED. Everyone I have seen for 
a long time has been. Even with that it worked fine with our GL. I’m wondering 
if someone installed the resistors or whatever is needed on mine to make it 
work.

Sent from my iPhone

On Aug 13, 2022, at 2:40 PM, dan penoff.com via Mercedes 
mailto:mercedes@okiebenz.com>> wrote:

Thanks for the insight, Jim, I was wondering this as well since the SAM drives 
it directly. However, when it was plugged into a “real” trailer we still got 
nothing.

I’ve got an 1157 lamp with some leads soldered to it - I’m going to try that on 
each terminal and see what happens.

Everything else has checked out. Now I’m wondering if the UHaul trailer *did* 
have LED lamps, as these do not work with this system for the same reason as 
above. I asked the UHaul guys if the trailer lamps were LEDs and they said no. 
Hmm. That would also explain why the diagnostic LEDs were lit on the adapter - 
it would only take a a few mA to drive them.

More as I know it.

-D

On Aug 13, 2022, at 3:07 PM, Jim Cathey 
mailto:jim.cathey...@gmail.com>> wrote:

And there is still power to all terminals at the 7 pin socket (except for 
trailer brake and ground.)

Power?  Or +12V measured with a multi-megohm input impedance meter?
(Zero current, essentially.)  Chances are it's got a pullup system, looking for
the load of bulbs to draw signals to ground so that the car can do lamp-out
checking, and trailer-plugged-in checking, etc.

-- Jim


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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[Buggered Benzmail via Mercedes]

Good work!  You learned something with all that sweat and effort!

I think my CL has some LED replacement bulbs in the headlights. They work fine 
but I get a whole bunch of warning messages on the instrument cluster. Might be 
some in the taillights as well. I haven’t chased them down yet since everything 
works but the nannies are Not Happy. 

I guess newer cars have LEDs so the new replacements will work straightaway but 
I wonder why there are no adaptations from the bulb manufacturers for backwards 
compatibility. 

--FT
Sent from iFōn

> On Aug 13, 2022, at 4:57 PM, dan penoff.com via Mercedes 
>  wrote:
> 
> Kudos to Jim for confirming the pull up voltage theory!
> 
> I believe there has been a comedy of errors that led to this situation:
> 
> 1.) The voltage at the 7 pin socket is a “pull up” voltage from the SAM and 
> won’t carry any current to speak of.
> 
> 2.) This voltage, while minimal, was enough to light the LEDs in the adapter 
> socket, which would explain why they were lit for the turn signals when the 
> signals weren’t on.
> 
> 3.) The UHaul trailer, despite what the lot guy told me, almost certainly had 
> LED lights.
> 
> 4.) The circuitry in the SAM has “lights out” functionality much like it does 
> for any other light on the body. This means it wouldn’t have played nice with 
> LEDs in the circuit unless there was a load resistor somewhere.
> 
> How did I confirm?
> 
> A tried and true and quite antiquated approach - an 1157 bulb as a test 
> light. When connected to the appropriate terminal on the 7 pin socket, would 
> light up and perform as expected for turn signal, brake light or running 
> lights.
> 
> So I burned maybe 90 minutes and five pounds of sweat chasing this down, but 
> now I have a better understanding of the system and discovered the location 
> of a number of different components on the car. And I got a full diagnostic 
> scan on it as well, showing almost 100% check marks, which is always nice.
> 
> I finished my time up with a good Martha’ing on the interior with the shop 
> vac, and even found a little bit of cruft in the cowl vents I had missed that 
> has now been vacuumed out.
> 
> Lesson learned. I need to find an adapter that will allow the use of LEDs in 
> the trailer harness. Time to play inside for the rest of the day and enjoy 
> the AC.
> 
> -D
> 
>> On Aug 13, 2022, at 4:10 PM, Kaleb Striplin via Mercedes 
>>  wrote:
>> 
>> The u haul trailer we rented a while back was all LED. Everyone I have seen 
>> for a long time has been. Even with that it worked fine with our GL. I’m 
>> wondering if someone installed the resistors or whatever is needed on mine 
>> to make it work. 
>> 
>> Sent from my iPhone
>> 
 On Aug 13, 2022, at 2:40 PM, dan penoff.com via Mercedes 
  wrote:
>>> 
>>> Thanks for the insight, Jim, I was wondering this as well since the SAM 
>>> drives it directly. However, when it was plugged into a “real” trailer we 
>>> still got nothing.
>>> 
>>> I’ve got an 1157 lamp with some leads soldered to it - I’m going to try 
>>> that on each terminal and see what happens.
>>> 
>>> Everything else has checked out. Now I’m wondering if the UHaul trailer 
>>> *did* have LED lamps, as these do not work with this system for the same 
>>> reason as above. I asked the UHaul guys if the trailer lamps were LEDs and 
>>> they said no. Hmm. That would also explain why the diagnostic LEDs were lit 
>>> on the adapter - it would only take a a few mA to drive them.
>>> 
>>> More as I know it.
>>> 
>>> -D
>>> 
> On Aug 13, 2022, at 3:07 PM, Jim Cathey  wrote:
> 
> And there is still power to all terminals at the 7 pin socket (except for 
> trailer brake and ground.)
 
 Power?  Or +12V measured with a multi-megohm input impedance meter?
 (Zero current, essentially.)  Chances are it's got a pullup system, 
 looking for
 the load of bulbs to draw signals to ground so that the car can do lamp-out
 checking, and trailer-plugged-in checking, etc.
 
 -- Jim
 
>>> 
>>> ___
>>> http://www.okiebenz.com
>>> 
>>> To search list archives http://www.okiebenz.com/archive/
>>> 
>>> To Unsubscribe or change delivery options go to:
>>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
>>> 
>> 
>> 
>> ___
>> http://www.okiebenz.com
>> 
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>> 
>> To Unsubscribe or change delivery options go to:
>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
>> 
> 
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> 
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Re: [MBZ] Trailer Wiring Confusion - ML550 - Bucket of Prop Wash/Snipe Hunt

[dan penoff.com via Mercedes]

Kudos to Jim for confirming the pull up voltage theory!

I believe there has been a comedy of errors that led to this situation:

1.) The voltage at the 7 pin socket is a “pull up” voltage from the SAM and 
won’t carry any current to speak of.

2.) This voltage, while minimal, was enough to light the LEDs in the adapter 
socket, which would explain why they were lit for the turn signals when the 
signals weren’t on.

3.) The UHaul trailer, despite what the lot guy told me, almost certainly had 
LED lights.

4.) The circuitry in the SAM has “lights out” functionality much like it does 
for any other light on the body. This means it wouldn’t have played nice with 
LEDs in the circuit unless there was a load resistor somewhere.

How did I confirm?

A tried and true and quite antiquated approach - an 1157 bulb as a test light. 
When connected to the appropriate terminal on the 7 pin socket, would light up 
and perform as expected for turn signal, brake light or running lights.

So I burned maybe 90 minutes and five pounds of sweat chasing this down, but 
now I have a better understanding of the system and discovered the location of 
a number of different components on the car. And I got a full diagnostic scan 
on it as well, showing almost 100% check marks, which is always nice.

I finished my time up with a good Martha’ing on the interior with the shop vac, 
and even found a little bit of cruft in the cowl vents I had missed that has 
now been vacuumed out.

Lesson learned. I need to find an adapter that will allow the use of LEDs in 
the trailer harness. Time to play inside for the rest of the day and enjoy the 
AC.

-D

> On Aug 13, 2022, at 4:10 PM, Kaleb Striplin via Mercedes 
>  wrote:
> 
> The u haul trailer we rented a while back was all LED. Everyone I have seen 
> for a long time has been. Even with that it worked fine with our GL. I’m 
> wondering if someone installed the resistors or whatever is needed on mine to 
> make it work. 
> 
> Sent from my iPhone
> 
>> On Aug 13, 2022, at 2:40 PM, dan penoff.com via Mercedes 
>>  wrote:
>> 
>> Thanks for the insight, Jim, I was wondering this as well since the SAM 
>> drives it directly. However, when it was plugged into a “real” trailer we 
>> still got nothing.
>> 
>> I’ve got an 1157 lamp with some leads soldered to it - I’m going to try that 
>> on each terminal and see what happens.
>> 
>> Everything else has checked out. Now I’m wondering if the UHaul trailer 
>> *did* have LED lamps, as these do not work with this system for the same 
>> reason as above. I asked the UHaul guys if the trailer lamps were LEDs and 
>> they said no. Hmm. That would also explain why the diagnostic LEDs were lit 
>> on the adapter - it would only take a a few mA to drive them.
>> 
>> More as I know it.
>> 
>> -D
>> 
 On Aug 13, 2022, at 3:07 PM, Jim Cathey  wrote:
 
 And there is still power to all terminals at the 7 pin socket (except for 
 trailer brake and ground.)
>>> 
>>> Power?  Or +12V measured with a multi-megohm input impedance meter?
>>> (Zero current, essentially.)  Chances are it's got a pullup system, looking 
>>> for
>>> the load of bulbs to draw signals to ground so that the car can do lamp-out
>>> checking, and trailer-plugged-in checking, etc.
>>> 
>>> -- Jim
>>> 
>> 
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