Dimitri. FWIW found this. I'm not familiar with that glow relay part number but I'll assume the connectors are compatible with MB passenger car harnesses and it's an afterglow relay. Forget the wire colors and check for pin numbers either on the relay itself or on the connector. The numbers should correspond between relay and connector pins. Here's the pin list for a 90-91 300D 2.5:
pin 1 = +12V when key switch in run to initiate preglow cycle (W124 = hot side of fuse 7) pin 2 = +12V when key switch in start to terminate preglow cycle (W124 = NSS) pin 3 = +12V to gauge cluster glow indicator pin 4 = ground pin 5 = blank pin 6 = signal from glow temp sensor by water pump to determine preglow and afterglow cycle times Assuming each glow plugs test between 0.7- and 1 ohm at the glow relay connector, leave pin 2 disconnected then see if you get the max preglow cycle of ~30 seconds. I don't know how the glow relay behaves when there is no temp sensor. If this gets to be too much work, a 617 pencil type glow relay should work for you since afterglow isn't much of a benefit in the tropics if you have healthy glow plugs. On Sun, May 14, 2023 at 11:29 AM Kaleb Striplin via Mercedes < mercedes@okiebenz.com> wrote: > It appears pin 31 is ground, connect a test wire from there direct to > ground and see what happens. > > > https://forums.mbclub.co.uk/threads/w124-continuous-voltage-to-glow-plugs-ignition-vacuum-connection.258241/ > > Sent from my iPhone > > > On May 14, 2023, at 10:18 AM, Dimitri Seretakis <dsereta...@yahoo.com> > wrote: > > > > It’s a brand new relay. I bought it at the stealership! Maybe it’s a > ground issue? Where is this thing grounded? > > > > Sent from my iPhone > > > >> On May 14, 2023, at 11:14 AM, Kaleb Striplin via Mercedes < > mercedes@okiebenz.com> wrote: > >> > >> There is no ecm that controls anything with the glow plugs. If the > relay gets power, but no power is coming out of the pins to the glow plug > harness, then the relay is bad. > >> > >> Sent from my iPhone > >> > >>>> On May 14, 2023, at 9:02 AM, Dimitri Seretakis via Mercedes < > mercedes@okiebenz.com> wrote: > >>> > >>> So I’m thinking that maybe the ground to the relay is the problem or > that there is an ecm issue. The relay gets power but doesn’t put out power > to the glow plugs. But where is the relay grounded? The three connections > are the power lug to the battery, the harness to the glow plugs and the > harness going to the ignition. The harness going to the ignition has 5 > wires. One gets power when ignition is turn to on position. I don’t know > what the other 4 do. Could one be a ground? I assume some go to an ecm. > Could a bad ecm be telling the gp relay not to send a signal to the plugs? > I’m about ready to give up and send this car to a mechanic! > >>> > >>> Sent from my iPhone > >>> > >>>>> On May 14, 2023, at 12:34 AM, Dimitri Seretakis < > dsereta...@yahoo.com> wrote: > >>>> > >>>> Yes my car has three connections as you describe. Big plug to glow > plug, cable to battery and small plug. Small plug corresponds to 5 pins on > relay. One connection on the plug is live only when ignition is turned on > so I presume that is the ignition on. > >>>> > >>>> Sent from my iPhone > >>>> > >>>>>> On May 13, 2023, at 12:37 PM, Jim Cathey <jim.cathey...@gmail.com> > wrote: > >>>>> > >>>>> Used to be there were THREE connections to the relay: > >>>>> A big plug that went to the glow plugs, a big cable that > >>>>> went to the battery, and a small plug that was command > >>>>> and control. The first two are Duh!, but they all need to > >>>>> be working correctly, or you don't get a good start. > >>>>> > >>>>> IIRC there was an ignition-on signal, a start signal, and > >>>>> a dash lamp signal. Ignition-on started the GP timer, > >>>>> start-release stopped the glow plugs, and the light was > >>>>> the light. > >>>>> > >>>>> Not sure exactly what your car has. Check the car schematic. > >>>>> > >>>>> -- 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 > >> > >> 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 > > 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 > > -- Fred Moir Lynn MA Diesel preferred _______________________________________ 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
