How to check temp unit/gauge?

[Ben Dover]

howdy All,
'82 K30 w/454.

how do I troubleshoot the temp sending unit and gauge? I've replaced the sending unit and checked the system with another gauge, and can't get a reading even with the engine hot.

I figure that I can't check it with a 12V probe, and I dont have a multi-tester. Is there some way to test the clips that the gauge mounts into? I'd be glad to pick up a multitester if someone can tell me how to check it.

Thanks!

Scott

[NeCrOmAnCeR]

Have you grounded the wire which leads to the sending unit? These gauges work by measuring the current flow through the guage/sending unit. As temperature increases, resistance drops in the sender and thus more current flows through the guage, deflecting the needle more. If grounding the sending wire with the ignition ON does not make the needle peg hot, check to make sure the guage is getting power. A meter would be the best for this, but a test light will work also. Clip the test light to ground and with the ignition ON probe both clips, one should light the test light, the other would measure the appropriate resistance for the temp of the engine. If the guage is getting power, and grounding the wire did not peg the guage, there is a problem with the wire from the guage to the sending unit.

[Ben Dover]

Thanks for the info!

I grounded the sensor lead and the guage didn't budge.

I also checked the 3 clips that the gauge slides into, and one (the top one) was hot, so I guess it's time to follow the wire!

Thanks again,

Scott

[NeCrOmAnCeR]

If the wire checks out OK, remove the instrument cluster and check the printed circuit on the back to make sure it is not damaged. And the last resort would be to replace the gauge.