Hello y'all! It's been a while since I posted on here. But I'm having an issue where if my car doesn't display the engine temp but just dashes, that the a/c doen't work. This randomly happens and not all the time but I have fixed or looked into this problem before but I can't remember what it is that I did. Can anybody help me?

 

Change your coolant temp sensor, they're fairly cheap and easy to replace

 

Never had though A/C problem but when my car did the dashes only and no temp replacing the temp sensor solved the problem

 

Thank you you guys!

 

Where is that sensor located?

 

Try good old google

 

Google would lead me to this. So I'm asking this forum. o_O

 

 

Well I fuxed and reset and it still comes back after a couple days as faulty, even when got another and replaced that. When I reset the code, then my a/c starts working with it showing the coolant temp. I don't understand what's going on. Any ideas guys?

 

Any ideas?

 

If you changed the coolant temp sensor, then you need to look at the wiring to it all the way back to the ECU. no for corrosion or faulty wires.

 

Ok. Will check and post back.

 

Thermostat...

Check Engine light on?

 

This problem still eludes me. It comes on and it goes off at times. So you think it I need to replace the thermostat? Could that be my problem? Because even now, the check engine light will be on and the a/c will still activate. When at first, when the check engine light is on is because of the temp sensor and when that is not working you'll notice the dash for the temp reading and the a/c won't come on. I'm so lost on this issue.

 

I'm having the EXACT SAME PROBLEM on my '08 Cobalt LS coupe. Started last week with the dotted lines on temperature with the check engine light coming on. Changed the temp sensor, unplugged battery to reset the comp and it worked great - for about 30 minutes. Same issue with the AC not kicking on.

I've read that there's a potential issue with the thermostat leaking by, because of a deteriorating gasket. This somehow affects the AC operation - my guess is, it's to protect the engine from overheating due to improper cooling?

I will be changing out the thermostat Tuesday afternoon and unplugging the battery to "reset" again. I will probably go ahead and flush the cooling system while I'm at it and add new GM coolant and a new radiator cap. I'll let you know what happens.

I've driven GM cars and trucks for 28 years. I think I'm finally getting to the point where I'm sick and tired of the odd, strange ways GM engineers their vehicles and makes it harder on the 'average Joe' to diagnose and actually fix their own stuff.

When I get this car back 'right' I might trade it in on a new Dodge Challenger....been wanting one anyway.

 

Im positive its your thermostat. On my 07 2.2l i had the same problem the gasket on the thermostat would tear and my coolant wouldnt show and a/c wouldnt work. You should get a check engine light and it should tell you its your thermostat from what i remember. And yeah sometimes it would work and sometimes it wouldnt. And well idk about dodge Electrical is pretty crappy this coming from a 16yr tech for Chrysler that i know. But your choice lol

 

Ohh btw you just spent money on the temp sensor also i had no need to reset the computer just put the new thermostat in and drive, the coolant temp should come back up or You probably dont even have to drive just start the car and everything should be fine

 

It's probably the thermostat as previously stated. I'm battling with that a lot lately. It's typically a P0128, which is "coolant temp under regulating temperature."

I'm seriously considering disabling the code with HPT until I can replace the stat.

 

Well replacing it took me maybe 30mins tops and i didnt know what I was doing

 

thermostat.

had the same issue, tried the temp sensor, and the connector for it. turned out to the the t-stat. super easy to change on my 2.4

 

How much a temp sensor run?

 

$10 shipped on eBay. Disabling code P0128 works so I don't have to constantly hear my fans and the car will actually get warm on the way to work! Yay!

 

Well around the same price as the thermostat lol well i guess thats not bad