Voltmeter and my temperature gauges are not working

Tiny
TWEBB101
  • MEMBER
  • 1984 CHEVROLET TRUCK
  • 7.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 1 MILES
Hello, my voltmeter and my temperature gauges don't work; needle looks to be broken as they are not pointing to any numbers. Is there a "common" reason for this? Or am I looking at new gauges? Maybe a new printed circuit board?
Friday, November 5th, 2021 AT 9:19 PM

7 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
The only thing that these have in common is the cluster so what I would do is remove the cluster and check the connections at the back and make sure there are no issues.

Then check the voltage at the meter as shown in the attached info below.

Here are a couple guides that will help with testing this voltage:

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

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

Please let us know what you find and what questions you have. Thanks
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Saturday, November 6th, 2021 AT 3:46 PM
Tiny
TWEBB101
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Great, thanks. Can these come out without removing the dash pad, or no?
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Saturday, November 6th, 2021 AT 4:54 PM
Tiny
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It has been a while but no. I think you can access all the screws around the cluster without removing it. The instructions I attached above do not say to remove it either so you should be able to get to them all. Take a look at the second page I attached on my last response and let me know if you need more info or how you make out.

Thanks
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+1
Sunday, November 7th, 2021 AT 6:16 AM
Tiny
TWEBB101
  • MEMBER
  • 178 POSTS
Lots of work done since last post, but I have replaced the voltmeter and oil pressure gauges (other gauges are backordered). I also replaced the circuit board, retaining clips, and lights. After starting the truck today, the oil pressure gauge was maxed at 60 PSI. Is that normal, or is something else faulty now?
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Friday, December 10th, 2021 AT 5:50 PM
Tiny
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  • MECHANIC
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It is possible that the gauge is accurate but if it is maxed out then the likely cause is the wiring is grounded and not running through the resistor in the gauge.

Basically, the way it works is there are two magnets that pull the needle to where it needs to be. So, one side is grounded, and the other side runs through a resistor which causes the needle to move through its sweep based on the sensor input.

So, if it is pegged in one direction, that tell me that the other sides magnet is not working which means that wire is grounded prior to the magnet.

So, we need to check for a short to ground or just run a new wire from the sensor to the gauge.
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Saturday, December 11th, 2021 AT 12:06 PM
Tiny
TWEBB101
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  • 178 POSTS
As a follow up to this: the oil pressure is running just under the 60 psi mark, so I think it's working ok? However, the voltmeter gauge is now having issues: it was working great, and then while driving it, the needle just jumped to 3 o'clock. When I turn the truck off, the needle goes back to 0; turn the key on. Back to 3. It's getting power, but no signal. I've checked all the wires, but no luck. Is there a fuse, or something else going on?
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Sunday, February 20th, 2022 AT 12:47 PM
Tiny
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  • MECHANIC
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Thanks for coming back to update us but we are going to have to get a new post started as we need to keep each post to the same issue. Basically, others that are having an oil pressure gauge issue will want to see how you fix yours, but they won't find it under this post.

https://www.2carpros.com/questions/new

Sorry for any inconvenience but when you solve an issue it not only helps you but all others that view this in the future, so we want them to find it.

Thanks
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Sunday, February 20th, 2022 AT 7:22 PM

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