so my coolant temp sensor is tweaking out on me.....

it will randomly read 260*+ then go down to -60* then back to normal and so on and so forth... you get the idea

ive changed sensors multiple times, changed pig tails, checked to make sure theres good continuity between the ground wire (which shares the same common ground with the TPS which is functioning fine so i highly doubt thats an issue) and also the yellow wire that runs to the PCM...

so im not sure what to do from here....?

 

Are the pins touching somehow in the plug or pigtail? Thats odd it goes both ways and not from the temp to 260 and back to temp, or from temp to -60 and back....

Time to sell the truck.

 

I'm in for this one... I have a somewhat similar problem mine only reads about 160 on the gauge but when I hook a scanner to it it shows 210 like it should be and sometimes once I kill it the gauges jumps to 210 like it should read

 

I know the stepper motors are weak and go bad on these trucks on the speedometer.... Possible same problem on the temp sensor??? I had a 2003 that I got fixed under a recall where the speedo. Amperage and oil pressure went bad.

 

Nope, that's why it had a new pigtail. The old one was all messed up so I thought that was the issue.

And it's not just the cluster because the scanner reads the same as the dash. And when all the sudden the temp goes from 190 to 260 it gets kinda hard to tune...

 

any more ideas for me to try when i get home??

 

Get 2 wires and run them straight from the pcm to the plug to rule out a wire broken in the harness.

 

Well I ended up pulling my PCM out just for the hell of it and apparently the way I have it mounted causes is to trap water in the connector because it was all wet and full of corrosion... So I cleaned it all out and everything seems to be working fine..? So hopefully that's it and I also dodged a bullet by cleaning it out before there was more issues.

 

Electrical gremlins are the worst .

Glad ya found a solution .

Question , would it be a wise idea to put dielectric grease on the PCM connectors to help prevent corrosion ?
I've been usin that stuff like Red Hot , " I put that **** on everything " lol

 

im going to get some tomorrow and slather it on!! im not 100% sure it fixed it but so far so good..... (fingerscrossed)