Pegged Temp Gauge...

[csx4590]

Shop took my '69 for it's final check ride today and the temp gauge goes all the way to the hot side. Changed the sending unit twice and the same thing. The gauges were restored about 8 years ago and recalibrated. Used a laser temp gun and it read 190 or less everywhere. I do not want to use aftermarket/under dash gauges. Are there any other things that could be causing this? Using an under dash unit temporarily just to keep tabs on it while I drive it the first few weeks. I can't wait any longer. It's been 12 years...

You guys have been great and appreciate all the help...

Al

[Dino]

If it's only the temp gauge then we can probably rule out that it's getting more than 5v.  The gauge may need to be calibrated again.  They can be finnicky to say the least.  Do you have another gauge for testing?  This can be the oil or fuel gauge.  If it reads correct just swap the faces.  I did the same to mine.

[birdsandbees]

If it worked before install, I can only suggest that the wire from gauge to the sender unit is pinched / bare to ground somewhere. Full ground = full scale.

[Pete in NH]

If it worked before install, I can only suggest that the wire from gauge to the sender unit is pinched / bare to ground somewhere. Full ground = full scale.

Hi,

If its only the temperature gauge that is pegging, this is very likely the cause. Try unplugging the sensor wire at the sensor, if the gauge still pegs there is a short in the wiring somewhere.

If the temperature gauge is the only gauge you have connected and the fuel and oil pressure gauge are not yet connected , it could be a bad instrument voltage regulator.

[Rolling_Thunder]

Mark sure you're using a factory Mopar temp sensor....    most part house sensors and aftermarket work on 0-90 ohms    mopar was 10-73 or something....     If you use a GM sensor on a mopar gauge the temp gauge pegs and you're at operating temp....      ask me how I know 

[69_Charger_RT]

Mark sure you're using a factory Mopar temp sensor....    most part house sensors and aftermarket work on 0-90 ohms    mopar was 10-73 or something....     If you use a GM sensor on a mopar gauge the temp gauge pegs and you're at operating temp....      ask me how I know 

Did not know that    So I take it the standard BWD or auto store sensor is garbage then.

[csx4590]

The other (fuel, oil and alternator) gauges work fine. The wire is off of the temp sending unit and the gauge is dead. Where can I get a Mopar sending unit? Are they still available???

Thanks...

Al

[68pplcharger]

Mark sure you're using a factory Mopar temp sensor....    most part house sensors and aftermarket work on 0-90 ohms    mopar was 10-73 or something....     If you use a GM sensor on a mopar gauge the temp gauge pegs and you're at operating temp....      ask me how I know 

Interesting, I'm having a similar issue with my water temp gauge. I'll check my resistance for my sending unit. It's an aftermarket sending unit for a Charger but reads about 40 degrees higher than the after market gauge i was using last year when I was testing prior to paint. If that's the case I'll just engineer a calibration circuit for the sending unit and leave it as is... lol helps having an electronic background. I will also test the voltage to the gauge and sending unit to be sure. The rest of the gauges seem to work great.