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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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09 HHR - - AC not cycling like it should. Condenser fan not

Customer Question

09 HHR - - AC not cycling like it should. Condenser fan not coming on when A/C is on but, it will come on with the water temp.
JA: Have you checked the Freon level?
Customer: Yes - - seems to be correct. I've even drained it to refill to the correct level.
JA: Are you fixing your HHR yourself? What have you tried so far?
Customer: Yes - - I replaced the pressure switch.
JA: Anything else you want the mechanic to know before I connect you?
Customer: I'm thinking it's an electrical thing.
Submitted: 2 months ago.
Category: Chevy
Expert:  david craig replied 2 months ago.

Hi Im David, thanks for visiting the site. tell me how you evacuated the system and if you pulled vacuum on it for at least 30 minutes. thanks. also did you use ac manifold gauge set to refill it

Customer: replied 2 months ago.
I vacumed it for about 30 min and used gauges to recharge. I have the equipment and maintain my vehicles. Curious about why the cond fan won't come on automaticlly when I select ac mode.
Expert:  david craig replied 2 months ago.

have you checked the condenser fan relay or fuse?

Customer: replied 2 months ago.
Honestly, I did not. Because the fan seems to be working just fine with the coolant temp. This is why I went to the pressure switch. I was thinking the switch was not allowing the circuit to complete.
Expert:  david craig replied 2 months ago.

not true. separate input

Customer: replied 2 months ago.
Hmm - - I see. I can check those out. But, do you know if the fan should come on any time you select A/C or defrost ?
Expert:  david craig replied 2 months ago.

the fan should come on within 10 seconds of the compressor clutch engagement

Customer: replied 2 months ago.
I see. So the clutch circuit is actually controlling the fan. Please bear with me - - electrical is my weakness ...
Expert:  david craig replied 2 months ago.

yes, but through a relay

Customer: replied 2 months ago.
I've pulled the clutch relay and swapped it out with the parking light relay. Same result.
Seems that the clutch circuit has a mind of it's on.
Expert:  david craig replied 2 months ago.

im not worried about the relays being bad. we need to find out if its getting the correct voltage to the relay. do you have a volt meter?

Customer: replied 2 months ago.
unfortunately I'm not with the car right now.
I was getting some very odd readings at the pressure switch connector. Was all over the place - - actually made no sense. I replaced the switch, bypassed the clutch and it came on. Then I plugged the switch back in, checked the freon level and cooled great. This morning it came on just fine and stopped on the first cycle.
Expert:  david craig replied 2 months ago.

sounds like maybe the pressure switch wiring

Customer: replied 2 months ago.
I acts like low freon. The label on the car says .09 lb. That would be about a can and a half of freon - - right ?
Customer: replied 2 months ago.
I looked at the wiring but did not trace it all the way. Could be your right. I will check that and fuses and relays.
Expert:  david craig replied 2 months ago.

yes

Customer: replied 2 months ago.
Can I get back to you later or will it be another tech ?
Expert:  david craig replied 2 months ago.

i will be me. right here

Customer: replied 2 months ago.
Thanks
Expert:  david craig replied 2 months ago.

you bet

Expert:  david craig replied 2 months ago.

hows it going?

Customer: replied 2 months ago.
I've discovered the AC runs and cools good when the cooling fan is running. I know how this works - - needs fan across the condenser to prevent high pressure. Here is the problem. If I turn the AC off or turn the ignition off and then back on, the clutch will engage on the compressor but the fan will not come back on. Therefore, creating high head pressure.
Something is wrong with the fan circuit in relation to the AC. Because, the fan will operate with the coolant temp as it should. The AC will then cycle as it should proiding the head pressure has dropped.
Expert:  david craig replied 2 months ago.

sounds like a pressure switch

Customer: replied 2 months ago.
it does - - I changed it. Could be the wiring - - but, cannot see anything wrong with it.
One other thing I've noticed is the Fan relay is really hot to touch. I changed it with a known good relay. Still the same.
Suppose the fan bearings could be going bad and getting tight with heat causing resistance ?
The car has 145,000 miles on it. Pretty sure it is the original fan assy.
Expert:  david craig replied 2 months ago.

spin the fan by hand. you should be able to feel if its smooth or not.

Customer: replied 2 months ago.
That was my plan this evening. Might even just put a new fan assy on it. They are not to expensive and looks real easy to change.
The fan circuit has a diode (#9). Have you ever heard of those going bad ?
Expert:  david craig replied 2 months ago.

yes sir. a few times.

Expert:  david craig replied 2 months ago.

you have a diode setting on your meter?

Customer: replied 2 months ago.
Not sure - - but, I have a few meters. Any idea what kind of reading it should have?
I was thinking they are either good or bad .......
Resistance on one side and not the other.
Expert:  david craig replied 2 months ago.

picofarads on one side something like .641 if i remember correctly

Customer: replied 2 months ago.
Actually - - the diode is for the clutch. But, I'll check it anyway.
Expert:  david craig replied 2 months ago.

ok. keep me posted.

Expert:  david craig replied 2 months ago.

just checking in to see how its going

Expert:  david craig replied 2 months ago.

what did you find out?