Triumph Repair: Temp gauge, test light, battery voltage

Question
Hi, The temp gauge on my '63 Spitfire is not working.  How do I check it?
Thanks, Ken

Answer
Hi Ken,

I don't have a diagram of a 63 Spitfire and even though I worked on them it is too long ago for me to remember. If it is an electric gauge, turn the key on and test both terminals for power with a test light or volt meter.

If you have power, go out to the temp sending unit and unplug the wire and watch the gauge. The needle should deflect all the way in one direction and then ground the wire and the needle should deflect all the way in the opposite direction. This is a rough test of the gauge and wiring. If it does that you probably have a bad sending unit. If it don't do that you may have a problem in the gauge or wiring.

If you didn't have any power at the gauge to start with, you need a wiring diagram to trace back from the gauge to what ever source it has. Many gauges used a voltage stabilizer to drop the voltage from battery voltage down to 10 volts. These are usually a small metal box with two terminals on it and are prone to fail more then gauges do. They are usually mounted either on the back of the speedometer or on the fire wall behind the instruments.

Howard