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sprinkles08, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 21416
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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My A/C is not working in '04 Grand Prix. A/C clutch not

Customer Question

My A/C is not working in '04 Grand Prix.
JA: Tell me a bit more about what's going on so he can help you best.
Customer: A/C clutch not engaging....A/C condenser fans not running. With A/C switch on, it only blows cool air.
JA: Are you hoping to fix this yourself?
Customer: I'd like to give it my best shot
JA: Is there anything else important you think the Pontiac Mechanic should know about your Pontiac?
Customer: I checked fuses and A/C compressor relay...they look good. I tried to by pass A/C compressor relay to engage A/C clutch with a jumper wire and clutch did not engage.
JA: Our top Pontiac Mechanic is ready to take your case. Just pay the $5 fully refundable deposit and I'll fill the Pontiac Mechanic in on everything we've discussed. You can go back and forth with the Pontiac Mechanic until you're 100% satisfied. We guarantee it.
Submitted: 7 months ago.
Category: Pontiac
Customer: replied 7 months ago.
Separate issue I've alternator is whistling...making high pitch whistling noise. Should I be concerned?
Expert:  sprinkles08 replied 7 months ago.

Hello and welcome to JustAnswer!

The alternator will make a small amount of noise during normal operation. If the noise is excessive it's usually from high charging system loads such as from a poor battery.

It sounds as if you have a failed compressor clutch. If you had power to the relay and jumped the correct terminals but the clutch didn't engage then you either have a failed clutch coil or an open circuit between the relay and compressor.

Can you check for power at the compressor using a test light with the relay jumped?

Customer: replied 7 months ago.
Hi Sprinkles,
as far as the alternator whistling, it's more noticeable at light acceleration. Also, if I roll a window up or down with my window switch, I can hear it whistling more.I spent some time today working on the A/C system. I completely evacuated my system with manifold gauge set and vacuum pump. I checked to see if I had any leaks from low and high side and after 30 minutes, found now leaks.
After that, I began to recharge my system with R-134a refrigerant. Half way through the first can of refrigerant, my A/C clutch engaged. Then both my condenser fans turned on. I let my system take the entire first can. All was well.
One thing I did notice, my A/C clutch did not DISENGAGE at seemed like it wasn't cycling like it should be.
I added another can of refrigerant thinking maybe the system was still low. Once I got the second can going, I checked inside the car and noticed I was getting decently cold air, but not freezing cold. It was about 88 degrees outside and had my car halfway in the garage while doing this.
Compressor clutch still did not disengage. I switched the A/C control off and the compressor disengaged.
Added another can and then drove the car a bit with A/C on. Stopped to see if A/C clutch was cycling on and off and it wasn't.Should my A/C clutch cycle on and off if my system is working properly and fully charged?
What would cause it to not disengage if it's supposed to?Thanks
Customer: replied 7 months ago.
Sorry...found NO leaks
Customer: replied 7 months ago.
I was doing some research on-line.
I came across an A/C cycling switch. These control the cycling of the A/C compressor.
Does the '04 have a high and low pressure cycling switch? I only noticed a high side cycling switch.
Would replacing this get my compressor clutch to cycle properly?
Expert:  sprinkles08 replied 7 months ago.

The compressor is only going to turn off it pressure becomes to low or high or evaporator temperature drops too low. It isn't a concern if the compressor runs constantly.

Customer: replied 7 months ago.
the compressor won't burn up if the clutch isn't cycling?Also, another minor issue I hope.
Before I read your last email telling me that it's not a problem, I thought I would try and remove the high pressure switch. Thinking it was more of a Schrader valve type switch, I started to remove it. As it was close to coming off, suddenly fluid and gas started shooting out. I eventually tightened it all the way back down so everything stopped flowing out, but a decent amount spilled out before I finally tightened it.
Do I have to re-do everything I had just done or replace any parts now that the system became open like that? Or is it ok and just add some more refrigerant to the system?
Expert:  sprinkles08 replied 7 months ago.

You don't need to be concerned with what the clutch is doing unless it doesn't engage at all or cycles excessively.

If refrigerant was lost then charge should be checked again because it will now be low, the extent depending on the size and duration of the leak.

Customer: replied 7 months ago.
Ok great!
Thanks for all of your help.
Expert:  sprinkles08 replied 7 months ago.

You're welcome!

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