Pontiac G8 Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter · #1 ·
so I have been having an a/c and heat issue for a while. I have been under the hood and checking fuses and relays and nothing seems busted. I havent been getting a temp reading of the outside temp since this started. I took to an a/c place and yhey couldnt figure it out, but I dont trust them due to the dact after getting it back from them I checked myself and the compressor belt was off. So I started checking some wiring and I dont have any power going to the a/c compressor, the fans, or the ambient temp sensor. My question is does anyone know where this wiring all meets up? There has to be something simple I am missing. How does just those things not receive power however everything else is alright. Thanks.
 

·
Premium Member
Joined
·
4,556 Posts
Well I see back in August of 012, you were adding some gauges and had the dash torn open. An that the problem you have *now* appears to be the same one that popped up after the gauge addition. Kinda sounds like the problem was induced *by you* at that point.
Since the ambient air temp sensor is wired to the HVAC controller (which is located just outboard of the fan per the drawing), sounds like to need to start there with your TS. Based on a code posted by you, it is seeing a short or open condition in that outside temp sensor (which equals no display). An that *would* mess up the normal control of that HVAC system.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #3 ·
I appreciate the help. I did not mention this was a new problem, nor did I say this was not something I may have accidentally caused. It seems unlikely installing a fuel pressure and oil pressure guage would cause this issue as they are tapped into fuses with nothing to do with the hvac. There is no power to the compressor, fans and temp sensor, I was wondering if there was a common point where these three intersec. Is anyone able to share a diagram of the wiring?
 

·
Premium Member
Joined
·
4,556 Posts
I posted it the way I did, due to what that post said. In that post, you said that upon completing the gauge addition, you noticed you no longer had any ambient readout and that the AC no longer works. It just seemed odd, that you ended up with that problem at that time.
For starters, the 2 engine cooling fans will only turn on if (1) the engine water temp reaches a certain temp threshold. So if your not overheating, no fan action. An (2) only if the AC is energized and told to put out enough cold air to raise the freon psi to a level that would command the fans to run in either both at low speed or both at high speed. The fan circuit is all in the engine bay and uses dedicated wiring runs from the underhood fuse box ( hot battery bus to relays to fuses to fans). With the relay(s) control wires looping back to the ECM.
To verify if both fans are operational, pull the R17 relay out. Bend a paperclip or a piece of wire ( an tape up finger area if desired), into a shape that will allow you to make contact with pin sockets 30 an 87. Both fans should run at the low speed. If OK, you only need to sort out the lost AC signal. I do see that the compressor and the ambient temp sensor wiring (both) go thru a common connector. I'll post up with some TS for that circuit, if you'd like.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #5 ·
Thanks, I think it is merely coincidence that the a/c went out after the guage install, it just seems weird to me. I do appreciate the help. I will have to test the fans then. Are these different than other cars then, when the a/c is on in my other car, a honda, the fans are running, at least when the compressor clutch is engaged. Im not exactly sure how these compressors work however. If you wouldnt mind showing that wiring schematic that would be great. Thanks.
 
1 - 5 of 5 Posts
Top