The temp. gauge on my truck does not read correct. Even after the truck has been running for about 30 minutes, the gauge moves up only to about 110 degrees. I have replaced both sensors, the one next to the thermostat housing and the other by the spark plugs. I have also replaced the thermostat and housing cause it was kind of bad. I replaced the radiator last year. I have a thermometer that I used on it and it reads 190 degrees. I removed the wire that connects to the sensor close to the spark plugs and grounded the wire and the gauge moves all the way to the right. What else can I check to get this gauge to read normally? Before I had this problem, under normal conditions, the gauge would be reading just under the 200 degree mark. Thanks guys for your help.

 

It is possible that you have the wrong sender for your application. I see that you changed it, but it is possible that you were sold the wrong one. it wouldn't be the first time that has happened.

 

Ok, thanks oldchevy. I will try a different one and see what happens. Hopefully, that will take care of the problem but if it doesn't, what else can I check? I understand that the sensor close to the thermostat housing communicates with the PCM. Could there be a problem with it. Maybe the wire from the sensor has a problem. Do you or anyone else here at this forum have a wiring diagram of the pcm that I can use to troubleshoot the circuits? I understand diagrams and schematics pretty well because of my experience as a technician. Thank you and all kindly.

 

Check all the wiring and replace the fuse. I can't say if it will help, but it won't hurt.

 

Ok, I will do that. Thank You.

 

The sensor to the guage is the one down by the spark plugs.

 

Well, I replaced both sensors, the cts and the one for the gauge and still reads low. Like I said, the gauge does read but does not rise to the correct temp. Could it be a faulty gauge. I hate to drive it like that, not knowing when the truck will be running hot and risking damage to the engine. I want to trace the wiring back to both the gauge and the computer but don't have the diagrams. Do any of you have this info that I can get from you? I am willing to pay for it. Thanks to all.

 

It's usually not the gauge, but it's possible. I assume you checked the temp with a temp gauge.in the radiator. BTW we do this for free, giving out advice, that is. It's rewarding when we can keep you'll out of the auto shop.We also learn from each other.

 

Thanks for your reply oilcanhenry. Yes, I did put my digital thermometer gun to the radiator and also to the thermostat housing and it reads 190 degree. I just have to keep digging til I find the problem. If any of you have any idea's or suggestions on this problem, please let me know. I guess I could try a under dash mechanical gauge to see how it reads but I don't want to do a mickey mouse job on this nice truck.

 

I would not want to, either. I'll do some more searching, and see what I can find, Birdman01. Whatever it is, 190 degrees F is normal.