AC question

[GeorgeG.]

I have an 03 Altima that the AC quit working a few weeks ago. It just blows hot air, compressor does not engage. So I'm thinking the freon leaked out and was going to recharge it with some r134a and UV dye. I buy a can that comes with the gauge from the parts store and when I connect it, the gauge says it's over 100psi and it will not take the freon. How can the pressure be so high when the compressor clutch is not engaged? Does anyone have any ideas on where I should start looking?

[Captain Crawfish]

first off go buy a real set of gauges forget that autozone junk they sell. go buy a set of quest gauges for 134a and get a reading off the high and low side. if the compressor isnt engaging its probably the low pressure switch which isnt allowing the compressor to engage. If you overcharge it you will blow out the seals on the compressor so make sure you know what your doing or youll wind up costing yourself a bunch more money.

[shumpertdavid]

several things could be the cause, first try to spin the outer compressor hub by hand(flat disc that is on outside of pulley) if it will not freely spin the compressor is locked up and the clutch coil is fried. If that is good, you need a decent set of gauges and a wiring diagram to see how the system operated electronically. The static pressure (pressure on system no operating) will be close to outside air temp. Example 80 degree day will have 80-90+ psi pressure static.

[GeorgeG.]

I can spin the clutch by hand pretty easy. I checked the voltage and I'm getting 13.x volts to the wire just before it goes into the compressor. I'm also getting 13.x volts on both sides of the 10amp fuse. I figured there would be a heavier duty relay but it doesn't list one on the fuse box sticker under the hood or under the dash.

I'll see if I can find some gauges next. The cheap gauge that came with the can of refrigerant said it was 125 psi.

Thanks for the help!

[Captain Crawfish]

harbor freight has some ac stuff thats not too expensive its not the best but it will work

[blackedv]

if your getting battery voltage to the compressor then the clutch coil is fried which can be changed without losing the refrigerant

[shumpertdavid]

if your getting battery voltage to the compressor then the clutch coil is fried which can be changed without losing the refrigerant

this is true, before tearing into it though make sure you don't have excessive clutch gap, should be no thicker than a business card. If you have a lot of gap, start the car, turn on the ac, and hit the clutch face with a broom handle, long prybar, or something with some length. If it engages you may just need to reshim the clutch gap. I have seen a rise in clutch coil failures the last couple years on imports though, not really sure why.

[GeorgeG.]

cool, I'll check it out. I tapped on it yesterday thinking it might be locking up but it didn't do anything. I'll hit it a little harder and see what happens. I looked on Autozone and O'Reilly and the clutch is not available separately, gotta buy the whole compressor...which sucks!!

I was also googling about this and came across some thread somewhere that says the thermostatic switch on the evap might be bad?? Not sure about that but that's what it said.

[shumpertdavid]

If you have power and ground at the compressor when you have everything on, then it should engage the compressor if the clutch is working properly, based on your earlier post you had power. You might check with the dealer on the clutch cost if the compressor seems to good. Sometimes the prices aren't too bad.

[JimD]

LOL @ stealership, prob the only place to buy clutch only. Pretty expensive compressor if i recall.