YotaTech Forums - Fuel and Temperature Gauges

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Fuel and Temperature Gauges

Hey guys,

I know this topic can be a tough one, but I feel like I've exhausted my options here.
I've got a tachometer cluster with round plugs on my 1979 4x4 Short Bed Pickup
Since ownership, the temperature and fuel gauges have never worked.
I've yet to verify anything coming from the fuel sender, but I have troubleshooted the temperature side of things
I have 82 ish ohms coming off of the temp sender in my 22r, and I also have 82 ohms at the Yellow/Green wire on the plug behind the cluster
There is 26.8 ohms between terminals A and B on the gauge itself; however after trying the plug in and check for volts on Term A portion, I'm stumped
I'm not sure where to ground when doing so, and when choosing the normal ground that I used to check ohms (dash clip bolt), nothing changes.
Is the cluster itself supposed to be supplied 12v from somewhere?
Am I missing something?
I will have the bed off tonight and while it's off, I will check my fuel sender, etc.
Lemme know what you guys think!

Edit. I've also taken the gauges out and tightened all screws, etc.

Sounds like you’re missing a wiring diagram?

But seriously... the 82 ohms off the temp sensor should change when engine is either hot or cold. You can also test it’s resistance by removing it and checking resistance at ambient temp, then again after submerging the probe side in boiling water (careful!).

I don’t have a diagram for a 79 or I might be able to help more. The sensor wire is plugged into which terminal at the gauge: A or B?

Also check your grounding point to a known good 12v source (a working light could be one).