1963 Dart Bad Temp Gauge Sending Unit?

[gage zamrzla]

I'm having some trouble and not getting a reading on my temp gauge in my 1963 Dart, 225 L6. I've tried a number of diagnostic tests and even replaced the temp gauge from a known working car and still no go. I think I've pinned it to the sending unit but am unsure.

The temp gauge has only moved twice in over a year and both times seem to be random where it would shoot up and drop all the way back down almost instantly. The connecter is new, and I've also tried cleaning and replacing the sending unit and nothing has worked. I've also touched the connecting wire to a hot surface and the gauge seems to go up accordingly when I compare it to the readings on my little laser thermometer.

I have no signs of overheating, (boiling radiator, spilling coolant, etc) and short of replacing the sending unit again I'm out of ideas and the problem I have there is there seem to be multiple part number sending units and I'm not really wanting to purchase a 3rd or 4th different one at this point if I can avoid ordering another wrong (identical looking) one. I searched through my 1963 Dart Dodge Polara Service manual and can't come across an actual part number to go off of so I was hoping unless someone had another suggestion someone could possibly tell me precisely which sending unit I would want to order.


Thanks in advance.

 

[halifaxhops]

Pretty easy to troubleshoot, here is what the ohms should be on the sensor. Usually it is a crap sending unit, the new ones suck.

If it checks out ground the sending unit wire and the gauge should go full. Then go from there. I possibly have some NORS ones that are way better than the new ones made today.

 

[RedFish]

Your instrument voltage regulator is inside the fuel gauge. The connection from limiter to fuel gauge is inside that gauge. The connection from limiter to temp gauge is via a fuel gauge post and the printed circuit board path to a temp gauge post.
Here is the most likely location of intermittent contact you describe.
One contact post of your fuel gauge has a odd metal clip in a larger square hole through the circuit board instead of a speedy nut like all the others. This was for venting some heat out of the fuel gauge and away from the circuit board. It was deemed unnecessary and replaced with a nut for 67 and later. They actually placed a bakelite cap over the nut and stud which bottled the heat without issue.

 

[gage zamrzla]

Great info and thanks to the both of you. I'll troubleshoot it by the weekend and report back.