Temp gauge 69 Roadrunner

[Mark05NY]

Ok electric guys!
Complete restoration. Soup to nuts. Dash, everything.
All was good, for a few days.
All of a sudden, I turn the ignition to the run position and the temp gauge slowly sweeps all the way full to the right (pegged past H) and stays there.
If I take off the wire at the sender, I have 10.7v with the key on. If I check resistance at sender, with it installed, I have 87 ohms. Engine warm to the touch.

Everything else works fine.

Any ideas on direction?

 

[Icecobra]

sending unit test for resistance

- - - Updated - - -

Check resistance at the sending unit

 

[Mark05NY]

So test beyond the way I did above?
I'm going to replace it anyway. Easy, cheap, just don't have one right now.

 

[Dennis H]

Using a laser temp gun, what is the actual engine temperature when on the H? Cold?

 

[bigmanjbmopar]

All other gauges ok?

 

[Mark05NY]

Engine is not over heating as the gauge slowly sweeps full over as soon as you turn the key to run. Even when cold.

All other gauges work fine.

 

[moparjohnny]

did you replace any of the gauges if you did not remember those gauges are 40 plus years old and i would just spend the money and replace all dash gauges especially the alternator gauge in which most power goes thru any way,people restore these cars and they forget that these old gauges are about used up and they complain about electrical problems in which they can not figure out,these old bulk heads and gauges and harnessess should be replace if you spending money on a resto,i hope your problem is simple and you can figure it out,sometimes old fuse boxes can be the problem.

 

[hunt2elk]

Sounds like the sending wire might be shorted to ground?

 

[bigmanjbmopar]

Sounds like the sending wire might be shorted to ground?

X2 sending unit