Help with Temp guage
Thread Starter
Racer
Joined: Jan 2000
Posts: 334
Likes: 0
Help with Temp guage
My temp guage stopped working. I changed the sending unit with no results. I then sent the guage back for repair and was told it was fine. What I need is a circuit diagram for the temp. guage circuit so I can go in with a meter and figure out what the problem is. I assume that the sending unit is a temp sensitive resistor and that the Temp guage is in series with that resistance. So that when a voltage is placed across the circuit, as the sending unit resistance changes the voltage drop changes across the sending unit and across the guage causing the needle to move. If someone can provide info on this circuit and/or trouble shooting it, I would greatly appreciate it.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Simple circuit, as you have described - gauge gets 12 volts, sender wire from the gauge grounds through a variable resistor (thermistor) in the sending unit. At room temp, sender alone should show about 600-700 ohms from the center terminal to ground. With key on and sender wire disconnected, gauge should show full cold (high resistance); ground the sender wire momentarily, and the gauge should show full hot (no resistance) - that checks the gauge function. 
