Temp Gauge

[biggreg70]

The temp gauge in my truck isn't working what could be the problem.
Thanks for the help

[fordman]

it could be the guage the wiring the fuse or the sender unit. i doubt the fuse. ground the sending unit wire and see if the gauge goes all the way to hot. if it does the sender is probably bad. if it does then the wiring gauge oor fuse could be bad.

[biggreg70]

Thanks ill check tomorrow

[robroy]

Good evening BigGreg70!

Sorry to hear your gauge isn't working! I think Fordman's technique is a great one.

If you do suspect that the sending unit is bad, you can test it! I tested mine just a few weeks ago.

Here's what my sending unit looked like. I'm not sure if you have the same one or not.





To test the unit, you measure the resistance between the silver, threaded rod on the top and the brass body. The resistance changes as the temperature changes, if it's working correctly. It should roughly match these values:



Here's Kasie and I doing the test. You'll probably need an assistant like I had! Just dip the brass protrusion on the end down in a pan of cool, warm, hot, and boiling water, taking resistance measurements at each stage.



Here are the values Kasie and I recorded for my sending unit:

Code: Select all

   Temperature          Resistance (Ohms)
   --------------------------------------
   Room temperature     315
   Hot tap water        185
   Simmering water      73
   Boiling water        33

But follow Fordman's advice! My tips will only help once you're suspecting that the sending unit is bad.

Robroy

[fordman]

i didnt know how to test a sending unit so you can check that too per robroys post.