View Full Version : Temp and Fuel guage not working

10-31-2012, 09:28 PM
Hello all, My 1974 Spitfire is causing me more electrical headaches. I recently had a friend wire up the birds nest behind the dash to get the bugs out. everything is in working order but the fuel and temp guage. I changed out the volt stabilizer after hours of research. I have a feeling it's a simple fix seeing that those two guages were working before my buddy cleaned it up. I cant seem to find a correct picture of where the ground wire attatches. Any ideas????

11-01-2012, 03:22 AM
Did you check for power to the voltage stabilizer (in and out) new doesn't always mean it works.


11-01-2012, 05:35 AM
The original stabilizer did not have a ground wire. It was grounded through it's mount on the back of the speedometer. If the replacement has a ground wire attach it under one of the knurled nuts that hold the speedometer in place.

11-01-2012, 06:34 AM
As above...
Switched 12V into the stabilizer on its "B" terminal,
10V out from the stabilizer on its "I" terminal (light green wires to gauges),
and the stabilizer case MUST have a ground connection (directly or by wire on its mounting screw).

With the original electromechanical stabilizer it is also important that it be oriented "correctly" when mounted. Correctly means... so you can read the letters "I" and "B" upright on the surface of the stabilizer where the terminals are located. Other orientations can slightly alter the output voltage.

When the ground is omitted the stabilizer passes full 12V which would make the gauges read high. Since your gauges are not working, look for a problem where the stabilizer is not getting the switched 12V supply. In normal Lucas wiring schemes that is a dark green wire coming from a switched terminal on the fuse box going to the stabilizer "B" terminal.

11-02-2012, 09:30 AM
Thats a great idea. I was just so frazzled i put the cover back on the car and walked away! I'll check power in/out.