Air Conditioning issue - 2002 Dodge Grand Caravan

pchicago

Hi Folks, first question here..

I had the compressor/clutch replaced on my 2002 Grand Caravan at the end of last year.. I recently went to have the system charged but the Compressor Clutch is not engaging

..The AC button-switch (snowflake symbol) on the HVAC control panel 'seems' to engage (light goes on) but the clutch doesn't kick in. He's got about 1 pound in the system..no clue as to pressures on high/low sides.

The light on the switch is on, but no joy on the clutch engaging.

He thinks the HVAC control panel needs replacing..based on the fact that the switch is a bit froggy..you have to toggle it a bit to get the light on the switch to turn on..

I've been taking my cars to this guy for 25 years and trust him completely..everyone in the area loves his work and his prices are honest and excellent..This is actually the first time I've done some checking on my own..Seems to me that if that switch light is on then it makes sense that it's sending power to a relay for the Compressor Clutch??

Before I go and dive into a new Control Panel I figured I'd do some research..so..any thoughts on this?

Wondering if the relay could be bad?

Could the compressor be sticking because it had no freon in the system for a while?

Any help appreciated..

Thanks.

Mr_Shiftright

Well the obvious next move is to test for voltage at the compressor clutch. If there is voltage, then the compressor clutch is no good (some compressors do not allow replacement of the clutch alone).

If there is no voltage, then a bad climate control unit is only one possibility. There is also a pressure switch which protects the compressor from engaging when the freon level is insufficient, or freon flow is interrupted for some reason (such as the system freezing up).

A computer scan might also reveal some issue in the HVAC system

Being an honest mechanic is not the point---sometimes you need to deal with an AC specialist.

pchicago

Shift..thanks so much. I don't have the tools for testing for voltage..

Wondering if I could jump the relay for the compressor clutch..located in the fusebox? Just to eliminate this part a s problem.

Does this make sense? Do you happen to know which pins I would jump?

socal_eric

Normally if you turn the ventilation controls to full defrost mode it will automatically engage the air conditioning. Might want to verify that's the case in your owner's manual and if so, give it a try and see if the system engages. If so but the manual switch isn't working in other modes that might be a reasonable guess (although instead of immediately replacing you should be able to pull the switch/panel out and jumper the wiring harness to rule it out and would probably be easier than trying to jumper the clutch directly).

Once thing that concerns me is stating you have a pound of refrigerant in the system but no idea of the high/low side pressure. if you're having a shade tree mechanic work on the A/C system and he can't afford and doesn't have the proper set of gauges (which a nice one can be found for under a couple hundred bucks) I'd personally take it somewhere else. Running the wrong pressure or refilling without properly evacuating the system is a recipe for potential failure of other expensive components down the road.

pchicago

Socal, He's a pro in a fully outfitted shop..has a steel canister with two gauges..pro set. When I picked up the car he said he thought it was the control panel..he sometimes lets me buy parts to save me money so I set out to do it..but then thought to educate myself a bit..sometimes even the best are wrong and we've tossed this around before..he's a good dude and always understands and learns..like I said we have a 25 year history and respect each other..He charged the system conservatively but wasn't getting the clutch to engage..

I have run the system in full on 'cool' already..no engagement of the comp clutch.