The problem you are discribing sounds like a "Grounded" gauge.
The Temp. Gauge works by the gauge getting voltage from your 12v 'keyed' source and then "grounding" through the Sending Unit mounted on the motor. This "Sending Unit" (which is actually 'receiving' a 12v signal) varies in it's resistance to ground as the engine temp changes. The Colder the engine the more amount of resistance (little or no gauge movement from lower temp readings), the Hotter the engine the less amount of resistance (the gauge reading climbs higher as resistance decreases).
If there is No resistance at all in the wiring to ground the gauge will swing directly to "Hot" when the key is turned to 'On'.
I would look for a "Short" to ground in the system - first try disconnecting the wire at the "Sensor" on the motor, if the problem goes away the sensor is bad - if the problem stays look for a "short" in the wiring path allowing the gauge to go to ground.
If you just installed the gauge package you may also have wired it wrong and provided a path to ground with your wiring.
My temp gauge is doing the exact same thing! Replacing my original console gauges with new aftermarket ones. The temp gauge worked FINE before I decided to swap them out. When I hooked up the new gauge, it pegs to the right? There is a ground wire running from the bottom terminal post to the gauge housing itself. All 4 lights are also working, as is the Amp gauge and the fuel gauge???? Don't even get me started again on the Oil pressure gauge!
I've tried manually jumping another ground from the bottom post to a good ground, same result. I've tried switching the two input wires around, then it pegs to COLD instead of HOT. Good grief, if it ain't one thing, it's another....... HELP!!!
Come on guys, help me out, I need ideas! I've searched the archives until my head is spinning, if it's not a bad ground, what else could it be? Could the resistor itself be bad? Would it cause these type of symptoms???
Make sure the sender and guage are matched. It's not uncommon to find an aftermarket guage has a temperature coefficient opposite the factory style. Measure the sensor resistance cold / hot. Ensure you can get that same reading from the sensor to ground and from the guage wire to ground. Disconnect the guage before ohming the line though. The guage probably won't be damanged if you don't but the readings will / may be affected.
So even though the gauge worked fine before, you're saying the reproduction gauge might use a different sender than the original GM gauge? The sender in the car now was purchased new at a local parts store recently, and when I asked for a temperature sending unit for a 69 Camaro with console gauges, that's the only one they had, and it worked fine. What other choices are there?
Anything is possible, but I'd certainly hope they'd be consistant with their part numbers. In any event, the ohm meter tests will help you determine if you've got a grounded wire, bad sensor, gauge wiring problem, etc.
I've tried switching the wires, when I do that, it pegs to cold instead of pegging to hot. I'm still thinking it's a bad ground, maybe the ground wire to the console base isn't making a good connection? I'll figure this out if it kills me......
A forum community dedicated to 1st generation Chevy Camaros owners and enthusiasts. Come join the discussion about performance, builds, restoration, modifications, classifieds, troubleshooting, reviews, and more!