'01 Malibu Temp Guage

Hi there,

My dealership has an '01 Malibu with an erraticaly inoperative temp gauge. I've isolated the issue to pin 5 of connector C2 of the ECU. What happens is that after 50 or so miles of driving the temp gauge will drop to zero. If I pull connector C2 and insert a bare wire in pin 5 and plug the connector the temp gauge will function again for around 50 miles and then cease functioning again.

On a hunch we tried inserting non conductive material in to the pin 5 socket of the connector, suspecting that the socket had galled out in some way (Leaving the copper wire in caused the cooling fan to run nonstop, presumably due to current bleeding over to the cooling fan output pin.). After doing this, the Guage remained functionl for a slightly longer period of time, but again failed.

I'm sort of at my wit's end trying to come up with a cost effective solution. I suspect that connector C2 in it's entirety will require replacement, but that will prove to be a costly fix.

Any input would be greatly appreciated!

Thanks in advance!

Pat

I have the same problem, The temp guage will not work for a time and it will trip the check engine light, also the fans run always run. I have replaced coolant temp sensor to no luck. Which connector and wire are u talking about or which color do i need to look for to see if it resolves my problem and maybe we can get it fixed. it driving me crazy to.

i had this for over two years..... just change the t-stat and it will be fixed

i had this for over two years..... just change the t-stat and it will be fixed

This is the correct answer. If you hook up a reader with "live" data displays, it will show that the sensor is working and the PCM knows the temperature, but for some reason the General turns off the gauge if the coolant temp is outside of the expected range :screwy: . Just change the thermostat.

(NOT as easy as you'd think - the air filter housing is easy to remove, but the t-stat is buried behind the exhaust manifold, under the throttle body, behind other cooling lines... and good luck finding an easy way to drain the coolant.

but I'm not bitter...)

Is this correct? I am having the same problem with my work car. If I put in a new t-stat my temp Gauge with start working again, and my fans will shut off?

Its less than a 10 dollar part, but a few hours labor. Anybody have any luck changing the t-stat without pulling the crossover pipe? Is it even possible?

Thanks in advance.

How the....why the ..... does the thermostat have anything to do with the temp gauge and fan operation???

Anyways, I changed it, took about a half hour. Took a little while to get the bottom bolt started.

I would of never thought it was that in a million years.

Oh well, thanks. See ya next time I have a problem. By the looks of things with these Malibu's; it won't be long.

This is the correct answer. If you hook up a reader with "live" data displays, it will show that the sensor is working and the PCM knows the temperature, but for some reason the General turns off the gauge if the coolant temp is outside of the expected range :screwy: . Just change the thermostat.

(NOT as easy as you'd think - the air filter housing is easy to remove, but the t-stat is buried behind the exhaust manifold, under the throttle body, behind other cooling lines... and good luck finding an easy way to drain the coolant.

but I'm not bitter...)

Holy Crap!!! I have had this problem for about two years also. I changed my intake manifold gaskets but didn't mess with the T-stat. Later my guage started acting weird. I am going to try this fix this weekend for sure!

Holy Crap!!! I have had this problem for about two years also. I changed my intake manifold gaskets but didn't mess with the T-stat. Later my guage started acting weird. I am going to try this fix this weekend for sure!

I would of never guessed this. It doesn't even make sense. But it will fix your problem. I use to work at a stealership, I saw a lot of funky problems. Never an electrical issue cause by a tstat. I tested my old tstat, it was fine.:screwy: