Instrument cluster does not light up

2000 GMC SIERRA
150,000 MILES • 4.8L • V8 • 2WD • AUTOMATIC
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SSROBERTSON
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I cannot get the instrument cluster to light up mileage, security, fuel level and temperature gauge. The voltage, speedometer, tachometer (I think), check engine light all come on. I bought a new body control module that was already programmed to my VIN and it does the exact same thing. Even swapped used gauge cluster from the junkyard and it does the exact same thing. I'm at a complete loss on this thing and just need some help. Thanks in advance for any help that can be given.
May 3, 2021 at 6:33 AM
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ASEMASTER6371
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Good morning again,

I attached a wiring diagram of the cluster for you to view.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-a-car-fuse

I also attached the connector. Check the pins I circled for power with the key on. If there is power, then the cluster is the issue. If you are missing power, then it is a wiring issue to the cluster.

Roy
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May 4, 2021 at 5:23 AM
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SSROBERTSON
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Thanks Roy, after testing pins above I found out that the orange wire was not getting power. Once hooked up the gauge cluster is now lit up correctly. The only issue now is that when I shut the truck off, the mileage screen and battery light is staying on. Was the orange supposed to be a constant on, or should it be a switched power?
May 4, 2021 at 5:52 PM
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ASEMASTER6371
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It is battery power. It should have voltage all the time.

Did you get power to the orange wire?

Roy
May 4, 2021 at 5:59 PM
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SSROBERTSON
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Yes, I piggybacked it on another wire that has constant on.
May 4, 2021 at 6:02 PM
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ASEMASTER6371
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Okay, I would have fixed that instead of that repair. Did you check the fuse for power on both sides for the orange wire?

If you have power now and the speedo does not work, then the issue is inside the cluster.

Roy
May 4, 2021 at 6:14 PM
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SSROBERTSON
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I checked the fuse and it had power on both sides. So when you say you would have repaired it, are you meaning run a new wire from the fuse block to the cluster? I can do that if it's what you recommend. I'm not sure if the speedometer is working due to it's not running and driving yet (still need to run that new fuel pump wire, lol).
May 4, 2021 at 6:19 PM
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ASEMASTER6371
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Correct. You have overloaded another circuit with your repair.

Run the new wire and make it correct.

Keep me updated on the rest.

Roy
May 4, 2021 at 6:30 PM
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SSROBERTSON
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Okay. I will keep you posted sir! Thanks for all your help again Roy!!
May 4, 2021 at 6:32 PM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
May 4, 2021 at 6:39 PM
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SSROBERTSON
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I did not get a chance to run new wires today. But I did verify that the speedometer is working (jumped the fuel pump off the battery to make run). But the message center and odometer lcd are staying lit up with the truck off.
May 5, 2021 at 5:09 PM
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ASEMASTER6371
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Back to the cluster itself.

Roy
May 5, 2021 at 5:14 PM
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SSROBERTSON
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Okay. Sounds good. Definitely making progress, and I may even get this thing done and not burn it to the ground (that's where I was at with it before your help lol). It's a project but had me stumped. Couldn't have done it without you Roy!! As always I will keep you posted.
May 5, 2021 at 5:17 PM
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ASEMASTER6371
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Sounds like a plan.

Roy
May 5, 2021 at 5:19 PM
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SSROBERTSON
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Update: I tried the second cluster I have and the lcd that shows mileage and gear shift position doesn't light up. So the fact of the original one staying on after the key is off I can only assume the cluster is the problem as you stated since I cannot verify otherwise.
May 7, 2021 at 2:42 PM
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JACOBANDNICKOLAS
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Hi,

We haven't heard from you for a couple of days. Have you replaced the cluster? Also, I do have diagnostics related to the cluster. Let me know exactly what is happening with yours. Hopefully, I will be able to find something specific.

Take care,

Joe
May 9, 2021 at 9:53 PM
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SSROBERTSON
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I haven't got a chance to replace the cluster yet. This is a project truck so I work on it in my spare time. My gauge cluster is staying on when I turn the key off. Specially the message center and the odometer lights.
May 9, 2021 at 9:59 PM
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ASEMASTER6371
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Take your time. We will be here when you need us.

Roy
May 10, 2021 at 3:06 AM
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SSROBERTSON
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Okay Roy, here's the update on the cluster: I bought a rebuilt cluster and installed it. I am having the same exact issues as before. Fuel gauge is not working, also the message center and the odometer/shift indicator are staying on with the key off.
May 28, 2021 at 9:37 AM
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ASEMASTER6371
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Okay, make sure the wires from the cluster to the fuel sender unit. Ohm them out and load test the wiring to be sure there is no corrosion in the harness.

Did you repair that broken wire or still have the overlay hooked up?

Roy
May 28, 2021 at 10:16 AM
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SSROBERTSON
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Is the ohm for the fuel sender the standard GM 0-90 ohm or did they change it on the newer stuff? And I still have that wire overlay because I cannot find a good spot to run it through the firewall and trace it to tap.
May 28, 2021 at 10:20 AM
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ASEMASTER6371
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Check the wires back to the sender. You should have a low voltage to the sender. About 7 volts. Then when the float goes up and down, resistance will change the voltage back to the cluster on the return wire. Check the wires first.

Roy

May 28, 2021 at 10:28 AM
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SSROBERTSON
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Okay. I will let you know shortly.
May 28, 2021 at 10:32 AM
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ASEMASTER6371
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Sounds like a plan.

Roy
May 28, 2021 at 10:37 AM
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SSROBERTSON
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It seems to be moving from .05 volt to just over 1 volt?
May 28, 2021 at 1:07 PM
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ASEMASTER6371
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If that is at the sender unit with the connector disconnected, then go back to the cluster and check the output from the cluster.

The cluster is what sends power to the sender unit itself. If you have around 7 volts, then you have a wiring issue from the cluster to the sender.

Roy
May 28, 2021 at 1:13 PM
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SSROBERTSON
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I will check. And I have a constant power at the orange and the red wire (next to the orange) with the key off. I just tested it to see if this helps?
May 28, 2021 at 1:34 PM
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ASEMASTER6371
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No, only test for power with the key on. You need the correct voltage from the cluster for the gauge to work. The gauge should not work with the key off at all.

Roy
May 28, 2021 at 1:46 PM
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SSROBERTSON
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I was referring to the fact of the cluster staying on with the key off. What color wire should I be testing at the cluster for voltage to the fuel sensor? I can't find it on the schematic.
May 28, 2021 at 1:48 PM
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ASEMASTER6371
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Okay, I sent another diagram for you. The 2 wires for the sender come from the ECM. I highlighted the wire. They are purple and orange/black. The purple is the sent voltage and the orange/black is the return. From there, it is sent by serial data line to the cluster.

Test those wires. The connector numbers are marked in the diagrams. The purple wire should have power back at the sender with the key on.

Roy
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May 28, 2021 at 2:11 PM
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SSROBERTSON
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I checked and I'm not showing any voltage on the purple wire right at the ECM.
May 28, 2021 at 3:09 PM
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ASEMASTER6371
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Okay, then you may have a bad ECM. I attached the procedure below.

Roy
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May 28, 2021 at 3:57 PM
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SSROBERTSON
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Not what I want to hear, lol. Is there any fuse that may be related to this issue? If this is the only issue I'm having can I get power from somewhere else?
May 30, 2021 at 10:24 PM
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ASEMASTER6371
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There is no fuse for this control and there is no overlay you can do to get it to work. Sorry, you need to replace it based on your results.

Roy
May 31, 2021 at 12:54 AM
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SSROBERTSON
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Okay. I appreciate that. As for the pink wire in the cluster that seems to be saying it's positive with the key off, the diagram you sent me shows ignition o volts, I don't understand if that is just supposed to be ignition "on" or something else.
May 31, 2021 at 3:18 AM
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ASEMASTER6371
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The ignition on, sorry.

Roy
May 31, 2021 at 4:19 AM
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SSROBERTSON
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It's just something funny I wanted to send you since we have been dealing with wiring issues.
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May 31, 2021 at 8:19 AM
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ASEMASTER6371
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Oh my goodness. What is that and how is it hooked up?

Roy
May 31, 2021 at 8:28 AM
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SSROBERTSON
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I'm not sure, it's just a picture I found online. It just feels like what I was doing with all the wires. Lol
May 31, 2021 at 8:30 AM
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ASEMASTER6371
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Is that what is under the hood of your truck? If not, why are you posting it? I do not understand.

Roy
May 31, 2021 at 8:32 AM
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SSROBERTSON
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It's not my truck. It was just something funny I seen on the internet and I wanted to send you for a laugh.
May 31, 2021 at 8:35 AM