temp & fuel gauges not getting power

'66 Mustang coupe

Some time ago my temp & fuel gauges quit working. Checked for voltage at the back of the cluster and I'm not getting anything at the fuel gauge (or temp). Ran a 12v wire from the battery to the fuel gauge and it started rising.

So I tested for 12v at the CVR on the instrument bezel, one side shows 12v, the other was fluctuating between 4-6v. As soon as I get home I'm going to check the voltages again - because it appears the CVR is what powers both those gauges, and if I'm getting the correct voltage coming from there than it should work.

What are some other things I can check to solve this issue?

can't be the ground, i hooked up a positive wire (12v) to the hot side of the gauge and it came on.

Replace the top-left blown fuse in my fuse box and it's still not working.

4tun8 said:

Constant Voltage Regulator is bad. I get this call all the time (I work at one of the leader Mustang Parts retail stores). I'd put money on it being the CVR.

Click to expand...

I checked it once more, 1 side is 12v, the other bounces from 0 to 5, 4, 0. Guess it is the culprit - though you would figure the gauges to read something with it bouncing between those values..


found this writeup: http://www.stangnet.com/mustang-forums/774198-how-make-solid-state-instrument-voltage-regulator.html


And will try the radioshack mod