Just a few questions. Can you start the engine? Are you sure the gauges are wired correctly?
I understand your confusion, just went through this myself. I will start with the temp gauge. The sender is screwed into your block, head or manifold. This contact grounds the sending unit. The ground is not complete until it gets hot when a bimetal contact expands inside the sender. The wire to the sender goes to the back of the gauge. The other wire on the gauge goes to the fuse block and is hot in the “on” mode. In a stock GM harness several hot leads come together and are simply twisted and soldiered in a bunch with tape wrapped around it. If you have a test light check both sides of the fuse with the key on and off. If the light goes on and off at the fuse box using the key repeat the test at the back of the gauge. If the light fails at the back of the gauge try using a jumper wire straight from the fuse box. If this fails run a wire to the sending unit. If this fails replace sending unit. The secret is start where you know you have power test each link until you lose the power then back track. The sender has a float like the one in your toilet. As it goes up and down the resistance changes. Under the carpet is a flat harness that has a connector under the dash and under the back seat. The tan wire can be tested at both locations, these do not usually fail. So if you have power at the gas tank sending unit skip, testing those connections. The fuel gauge sender has one tan wire (hot) and one black ground. Check the tan wire with the test light. Turn the key to “on’ before you get under the car. If it is hot at the sender I would make sure the ground wire is good. The test light ground wire should be clipped on the sender where the normal ground wire is attached and the probe inserted into the connector on the tan wire this way you test your ground. If it fails move the ground of the test light to some part of the body. If it works then I would replace the end of the ground wire and clean all the rust around the screw hole in the body. One trip under the car is enough. If all this does not help I would suspect that you have wired the gauges incorrectly. From: chevelle-list-boun...@chevelles.net [mailto:chevelle-list-boun...@chevelles.net] On Behalf Of rml...@comcast.net Sent: Tuesday, February 02, 2010 7:54 PM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] wiring question Jim I appriciate your help. It seems to me Iam being told 2 different things here. Leo say's there should be no power at pins 10 and 11 and it sounds to me like your telling me there should be power at those pins. I dont understand the principles of operation here. I dont understand how they work.I hope someone here can explain to me exactly how it works. Does 12 volts go through the guage and the sending units add resistance to ground. Thanks every body for your help here. I just wanna get my guages working. ----- Original Message ----- From: "Jim Thompson" jimthompso...@gmail.com To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Sent: Tuesday, February 2, 2010 7:10:29 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question I will suggest again that ground is critical. Your fuel sending unit should have its own ground wire. The temp sending unit is hot, internally the switch closes to ground. With the key to “on” both should be hot. Your fuse box should have one fuse marked “gauges” if it is hot on both sides. Then it is a ground issue or short in the gauge harness. From: chevelle-list-boun...@chevelles.net [mailto:chevelle-list-boun...@chevelles.net] On Behalf Of rml...@comcast.net Sent: Tuesday, February 02, 2010 4:25 PM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] wiring question Does anyone know where the voltage for the fuel and temp. guages is fed from. I have voltage to everything except these two guages. I unplugged the 12 pin connector that plugs into the pcb and checked for voltage there. everything is hot with the exception of temp and fuel. all my fuses are good. Any ideas.Thanks, Bob ----- Original Message ----- From: dhoesc...@granitecityperformance.com To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 10:03:58 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question I would suggest disconnecting the tan fuel sender feed wire at the fuel tank. Turn the key to RUN position and wait a few moments (some gauges are slow) with the tan wire disconnected the fuel gauge should read past full. Then ground the tan wire anywhere to the body and the gauge should read empty. If you get no response then you have a bad gauge or a wiring problem. -----Original Message----- From: "Tom Rightler" <bluess...@comcast.net> Sent: Monday, February 1, 2010 20:47 To: "'The Chevelle Mailing List'" <chevelle-list@chevelles.net> Subject: Re: [Chevelle-list] wiring question If you want to check the gauges, send 12 volts directly to them and see if the needle moves. If the needle moves, the gauges is good and there are wiring issues elsewhere. I’ve seen brand new sending units fail. There should be 12 volts at the bulkhead connector with the key in the run position for all wiring to the gauges. Tom -----Original Message----- From: chevelle-list-boun...@chevelles.net [mailto:chevelle-list-boun...@chevelles.net] On Behalf Of rml...@comcast.net Sent: Monday, February 01, 2010 9:01 PM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] wiring question The sending. unit is grounded to the body, and the temp sending unit is new. Tom,do you know if there would or should be voltage at the 12 point connection into the pcb. for the temp and fuel guages ----- Original Message ----- From: "Tom Rightler" <bluess...@comcast.net> To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 8:53:30 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question Is the fuel sending unit grounded to the body? If the temp gauge isn’t working, it’s usually a problem with the sending unit screwed into the head. Tom Rightler MCC Newsletter Editor http://www.chevelles.net/mcc -----Original Message----- From: chevelle-list-boun...@chevelles.net [mailto:chevelle-list-boun...@chevelles.net] On Behalf Of rml...@comcast.net Sent: Monday, February 01, 2010 8:32 PM To: The Chevelle Mailing List Subject: Re: [Chevelle-list] wiring question I'am a firm beliver that there is no such thing as a dumb question. My dash lights are working fine. the dimmer switch is working I just dont have a temp. guage or a fuel guage. ----- Original Message ----- From: dhoesc...@granitecityperformance.com To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 8:25:13 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question Forgive me if it's a dumb question...did you try rotating the knob? I don't know if 1970 had the "dimmer" built into the headlight switch perhaps it's turned down to the lowest setting or the rheostat is burnt out? Second, did you check for power at the fuse? -----Original Message----- From: rml...@comcast.net Sent: Monday, February 1, 2010 19:08 To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Subject: Re: [Chevelle-list] wiring question Yes I do have a schematic. I have a 70 ss with guages. Iam just not sure why the guages are not working. ----- Original Message ----- From: dhoesc...@granitecityperformance.com To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 7:27:55 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question Do you have a wiring schematic -or- would it help if you had one? What year Chevelle do you have? -----Original Message----- From: rml...@comcast.net Sent: Monday, February 1, 2010 17:02 To: dansolo...@msn.com, "The Chevelle Mailing List" <chevelle-list@chevelles.net> Subject: Re: [Chevelle-list] wiring question Dan, The guages are not new nor is the engine harness or the dash harness. And no the guages did not work before. I was hoping that putting a new pcb. in would get them working. All the wiring is still original to the car. I did put voltage to the gas guage when I had it on the bench and was able to get movement. I used a 9 volt battery and the guage moved to around 1/2 tank. I then reversed the polarity and the guage went back to E. So with that said I kinda assumed the guages were o k. I really appriciate your efforts, Keep pitching maby eventually I'll get a hit. Thanks Bob ----- Original Message ----- From: "Dan Solomon" <dansolo...@msn.com> To: "Chevelle List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 5:34:52 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question Are the gauges new? How about the dash harness and the engine harness? Did the gauges work before you made your changes? The reason I ask is that the pins are in different locations at the firewall. If one harness is from a 70 and one from a 71-72 that may cause your problem. Thanks, Dan -------------------------- Sent using BlackBerry _____ From: rml...@comcast.net Date: Mon, 1 Feb 2010 21:54:45 +0000 (UTC) To: <dansolo...@msn.com>; The Chevelle Mailing List<chevelle-list@chevelles.net> Subject: Re: [Chevelle-list] wiring question Dan, I did ground the cluster with one of the screws that attach the metal to the plastic housing. And all my lights are working, dash lights, head lights, but none of my guages are working. Fuel, temp, or amp. All of my fuses are good. Any ideas. Thanks Bob ----- Original Message ----- From: "Dan Solomon" <dansolo...@msn.com> To: "Chevelle List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 4:41:31 PM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question Bob, I don't remember if all of the wires in the connector are hot but you do need ground to the cluster. Use one of the screws that attach the metal cover to the plastic housing. Don't use the ones that attach the PCB. When you say your lights are working do you mean dash lights or headlights? Thanks, Dan -------------------------- Sent using BlackBerry _____ From: rml...@comcast.net Date: Mon, 1 Feb 2010 20:56:09 +0000 (UTC) To: The Chevelle Mailing List<chevelle-list@chevelles.net> Subject: Re: [Chevelle-list] wiring question Thanks, Dan. Should I have a voltage at each pin on the 12 pin connector.ie.the fuel, temp, and amp. My lights are working, I didn't put a ground on the guage cluster itself. can that go on any screw on the back of the cluster. All the screws on the back go through the pcb. ----- Original Message ----- From: "Dan Solomon" <dansolo...@msn.com> To: "The Chevelle Mailing List" <chevelle-list@chevelles.net> Sent: Monday, February 1, 2010 10:04:44 AM GMT -05:00 US/Canada Eastern Subject: Re: [Chevelle-list] wiring question I had a hell of a time with the dash in my 70. Must have pulled it out and put it back in 6 times. Make sure that you have the three black ground wires hooked up. One goes to a screw on the cluster, one to the metal frame of the dash carrier and one to the e-brake. Also did you put the ground strap back in under the light switch? My problem turned out to be the headlight switch. Power to the cluster passes through this switch. One of the spades slipped out aside the connector and was not making contact. Here is the topic on chevelles.com. It has some great pics and information to diagnose the headlight switch. It also includes information on the 12 pin connector and tests to verify voltage at the fusebox. http://www.chevelles.com/forums/showthread.php?t=260728 <http://www.chevelles.com/forums/showthread.php?t=260728&highlight=hot+wires+SS+dash> &highlight=hot+wires+SS+dash Dan "It is a mistake to allow any mechanical object to realize you are in a hurry." http://www.freewebs.com/chevelles1970/ _____ Date: Mon, 1 Feb 2010 10:06:28 +0000 From: rml...@comcast.net To: Chevelle-list@chevelles.net Subject: [Chevelle-list] wiring question I set my restored dash in place and connected the wires, turned the key to acess. and my temp. fuel, and amp guages did nothing. Should there be a voltage at the 12 point plug for each of these three guages. My dash lights work. Turn signals work. brake lights. All the lights are working. Iam stumped. Any ideas,Thanks. Frustrated. No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.733 / Virus Database: 271.1.1/2662 - Release Date: 02/01/10 07:37:00 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.733 / Virus Database: 271.1.1/2662 - Release Date: 02/01/10 07:37:00 No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.733 / Virus Database: 271.1.1/2664 - Release Date: 02/03/10 14:35:00
