Temp gauge has been staying barely over the 155 mark. I know it's wrong because thermostat opens and computer shows actual temp around 190. Did the test where you ground the connector and gauge jumps to full hot, which I read means the gauge is fine. But after putting in a new temp sending unit the gauge still behaves the same. Mostly reading low, but one time it went to 210 right after starting truck, then dropped back to the usual position just over 155 once the truck warmed up. Any ideas on what could be causing this?

 

Did you use a Genuine GM sensor? Any aftermarket sensor is not trustworthy.

 

I didn't realize that and I don't know if the old one was original. Gauge is acting exactly the same with new and old. I may order a GM and return the other as defective.
On these the single wire goes directly to gauge correct? With nothing else in between that I should check?

 

I've read some people say teflon tape adds too much resistance. Some say that's hokey. The new sender came with a pretty thick teflon wrap. Anybody here have issues with that?
Also how might I test the ohms at the connector? What readings? I saw that mentioned somewhere but can't find it now...only the testing for the dual wire sensors. This is single wire. Or way to hook up an external gauge to compare against the one in cluster?

 

My 1999 Suburban has this exact same problem. Temp gauge always reads 160 degrees, but OCII says temp is 195. I just replaced the temp gauge sensor, but that did not change the temp gauge reading. Seems odd to physically reposition the needle. Any other suggestions?