View Full Version : Gas and Temp gauges not working

04-20-2017, 01:13 PM
Was working on my '58 instrument panel and like a dummy, did not disconnect the battery. Touched something and got a spark. Now the Gas gauge and Temp gauges won't work. Is there a fuse panel or just an in-line fuse that could be the problem?
Could it also be a blown/defective Constant voltage regulator?
Appreciate any help you can give me.

04-20-2017, 01:29 PM
It is possible that 12v got through the CVR unit and shorted it out. That unit downsizes the 12v to an undulating voltage of no more than 6v because your gauges are 6v gauges. That could have fried the wiring leading from the output of the CVR to the input of the gauges. That is what happened to mine... Twice. The last time, I replaced it with a solid state version that prevents 12v from being passed through. It could also be other problems that caused the gauges to stop working and I will leave that to John~jopizz, Dave~simplyconnected, or others to suggest what else to look for.

IF it turns out that your CVR is fried, considering becoming a Paid Member of this Forum. Our webmaster, Dave~simplyconnected, offers Paid Members a deal on replacing their OEM CVR with a solid state one that will NOT fail and damage your gauges.. For more information on this, go to Post #1 on this thread, in Anything Goes Forum.


04-20-2017, 01:53 PM
There are no fuses for your fuel and temp gauges. As Ray mentioned it's most likely your CVR that got fried. Having yours converted to solid state will be more reliable in the long run. You are probably going to pay at least $30 for a new non-solid state one anyway.


04-20-2017, 02:22 PM
The disadvantage of replacing it another OEM type CVR unit is this. Some of the Tbird parts houses have told me that the present CVR units are being made in China. As a result, they have been known to fail. So instead of going for my third OEM CVR, I went with a solid state one. But that one I bought is more expensive than the deal that Dave ~ simplyconnected can give you.. And he guarantee's his for the life of the unit.

04-20-2017, 04:02 PM
Is this that plug-in unit located on the back of of the instrument cluster by the fuel gauge?

04-20-2017, 04:21 PM
Yes, in some cases it is often found mounted on the back of the instrument panel by the gauges. I found mine mounted to a metal frame post for grounding. Here are a couple of pix that you can see where it is located at.

04-20-2017, 04:49 PM
Using Dave's would be an excellent choice.

Now . . . while you are getting these systems into working shape again. Find where each one grounds out and clean up
the ground. This will help to give more accurate results.

The fuel sending unit is in the trunk under the mat. Do what it takes so that the contact between the unit and the body is A-1.

The temp sending unit is on top of the manifold in front. Clean up the electrical connection. Consider a jumper from the body of the unit to a good ground. I would suggest removing it and cleaning the threads but I think it is below tank level and hence you would have coolant running out. So leave well enough alone but do what it takes to cause a good ground.

If you have someone with a hand held temp gun you can even calibrate it when things are working again. Meaning associate a real temperature with each letter: T E M P.

But first things first . . . restore the 6 V source. Be glad it failed in the Open position (no voltage) and not in the Closed position (12 V) as the latter would have fried your gauges leaving you with a messier problem to solve. (all the old style voltage regulator was, was an oscillating On/Off mechanism that averaged out to 6 V between being closed (12) and open (0) )


04-20-2017, 05:04 PM
I purchased one of Dave's and it's been hassle free.

Most important however, ALWAYS disconnect the battery FIRST! I've learned that the hard way too!