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69 Super Bee Temp Gauge


Local time
4:05 PM
Jun 3, 2019
Reaction score
Houma, LA
This one has been driving me nuts lately. I‘ve been fighting with getting the factory temp gauge in our 69 Super working again. It previously was working fine, then one day while my father was driving the car the gauge started it’s normal climb as the car was heating up then suddenly just dropped down to the stop.

I did some reading and started by using a piece of wire to ground out the wire for the temp sensor, which caused the gauge to rise up like it should. I did not hold it long enough to peg the gauge because I know that can cause issues. I also metered out the wire to the sending unit and was getting the proper 5vdc. The rest of the gauges in the car are working fine, so everything seemed to point to the sending unit being the culprit.

I replaced the sending unit with a new one that I ordered from Classic Industries and I’m still experiencing almost the same exact behavior. The gauge seems to come off the stop, but it never moves past the 120 mark even though the car is up to temp and running about 180 F. I again went through today and double checked the voltage at the sending unit and grounded it out with the same results as before. I don’t seem to have any ground issues that I can find since everything else such as oil pressure gauge is working perfectly.

Could this really be a case of the new sending unit also being bad? Or is there something else I’m missing?

Also, picture of the car just for fun:

Probably crap from Classics. Post a WTB for an old OE one here and someone will get you a "new" one. A correct 250F Rallye gauge sender should read about 300 to 340 ohms in a 70F shop
Shop around for a Standard Motor Parts TS17, excellent part sells for around $10. Works fine..

Just my $0.02...
Maybe try a 73 and a 10 ohm resistor between the sensor plug and ground? 73 should read low and 10 should read high, seems weird it would drop off that much but maybe the gauge needs to be calibrated?
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