Hey this may be a stupid question but it would be even stupider not to ask. Is there any circumstances that would make the a/c compressor clutch engage when the cooling fan comes on. What I mean is, what if the temp was getting higher that what would be normal, would there ever be a case where the a/c engaged to help with the cooling? Because one thing I have noticed which may or may not be normal is that the car gets pretty hot before the cooling fan comes on. I know it didnt use to, but a couple years back when I was trying to fix this same problem before one of the things I did was replace both t stat sensors. And since then it has gotten hotter before the cooling fan came on. It gets to about 2mm past the half way point on the temp gauge.

Now the issue with the a/c clutch was already happening when I changed those, so I know that didnt cause the problem, but I have a feeling that this might be a problem all on its own. So what is normal temp as far as the temp gauge for the cooling fan to come on? Normally its about 1/4 of the way up, but in park, or idling in traffic it can get all the way past the half and then the cooling fan comes on.

PS: Thanks again for all the help.

 

When the engine is running, the fans should turn on when the coolant reaches 200F. When the engine is not running, one of the fans will turn on when the coolant reaches 223F.

I wonder if you switched the sensors when you installed them? They are both open/closed circuits. They just close the circuit at different temperatures.

One way to test is to unplug temp sensor b and measure for open/closed while the engine is running. If the circuit goes to closed before the fans turn on, then you may have switched the sensors. Another way is to boil water (212F). Hang each sensor into the water. See which one reads open and closed?

 

Would the sensors being reversed cause something like that?

 

That could delay the fans turning on, because the coolant would need to be hotter for the temp sensor b to turn on.

I am not sure if there is anything stamped on the sensors that can identify them from each other. It may not even be possible for them to be switched.

 

Maybe the plugs are different so if you had the wrong one in you wouldnt be able to plug it in. But what I meant was do you think theres anyway that the sensors of t stats being reversed might cause the a/c clutch to engage when it isnt suppose to? I know Im grasping at straws here, but Im desperate to finally figure this thing out.

 

That shouldn't cause the problem with the a/c.

 

I read through this and might have missed it, but have you tried diagnosing the switch in the dash used to turn the AC on? Try unplugging that, and see if it still happens. Could be one of those things so simple it gets overlooked. If it has been mentioned, I apologize.

Interesting thread, BTW.

 

Actually no I havent tried that. But I have a question regarding unplugging the a/c switch to test if it happens with it unplugged. Is that going to actually tell me anything? What I mean is if it doesnt happen when the a/c switch is unplugged that doesnt necessarily mean that that was the problem right? Because it would be removing one of the needed parts of the circuit for it to work. Like pulling a fuse, by pulling the fuse the circuit cant complete so that isnt actually diagnosing it is it? If it is let me know. It would be awesome if it was something as simple as that.

 

Actually, it can work the other way. If you unplug the switch, and it STILL comes on, that proves the problem is not in the switch.

You can also remove the switch and check the circuits within the switch. On or off, which terminals have continuity between them. Can you make or break continuity by wiggling anything? Pressing the switch in any oblique direction or ???

 

I know this has been asked before, but are we absolutely sure that the compressor clutch is NOT suppose to spin when the cooling fan comes on? Ive been wanting to find someone with the same car to see if theres does the same thing or not.