Sunday, November 4, 2012

2006 VW Jetta Air conditioner Problem

Volkswagen jetta A/C is not blowing cold.

The compressor is replaced,receiver/drier is replaced,expansion valve is replaced,also refrigerant is filled.

The compressor is getting 14v from the wiring harness but the high and low side of the system both stay at 80 psi

Note:-- On 2006 VW jetta model there is no clutch it has a compressor control valve.

The voltage goes from 0v to 14v when the auto function is turned on and off, you can say the clutch signal is turning on and off with the AC being turned on.So the voltage goes from 0v to 14v.

The better possible details regarding the problem:----

If you are getting power to activate the compressor and only seeing 80 psi pressures on both low and high side port,then either the pump isn't turning on or it is weak/wiped out and equalizing.

If your pressure is static at all times like it sounds, then that pump isn't turning. The pump is turned on via 12V to the control valve and a fixed ground..... meaning since you have 12V with the AC turned on, you either have a bad regulator valve/compressor (not too likely since it is new) or a damaged ground wire from the valve.

Get these possibilities checked first.

Also while filling refrigerant in new A.c system place it in a vacuum first.

Pull a vacuum on the system down to -30 inhg for half-an hour. Then let it to sit for about 30 mins to ensure there are no leaks in the system.

After that you can recharge the system as per specifications came with compressor manual or as per vehicles owner's manual instruction for recharging A/C system.

Test the voltage at the wire coming out from compressor connector.
There will be two wire,one negative and other positive.

You should get 12V signal coming from the AC control head and ground wire going to the front body ground. The 12V signal is turned on/off by the AC control head.... the ground never changes. If the 12V is there from the control head and the pump is not coming on, either there is a problem with the valve/pump or there is a problem with the ground wire.

As its already mentioned that there is 14v on at compressor control valve,if you have voltage at the regulator valve, that is what turns it on. If it isn't turning on, there is something wrong with the valve or the compressor is bad.And compressor is new and valve is getting voltage so the   fault can be pump not turning ON.

If pump is checked ok,then may be new compressor unit is come faulty.In rare cases such things happen.

Another possibility, if for example the pressure switch goes out of range, it shuts down the AC as a safety mechanism. These happens, By cutting the power to the regulator.


one more thing you can try and check is ,

Connect the connections directly and see if compressor opeates or not,

See if you can hear the valve change when you apply voltage and ground and when you remove it (engine off so you can hear). If you can, the only other thing is problem with plug in the line ports of the compressor that you didn't see.... though on this one the plugs usually are large/bolt on if you get an OEM unit.

Also this compressor has an internal safety switch in-case if  there is a low freon scenario.

The line pressure switch is the low pressure safety.
The compressor has a high pressure safety that is a valve that will discharge refrigerant over ~450 psi or so.

Do the direct connection (both 12V and ground) and listen for activation.

You just put a direct connection to the compressor from the battery .The battery is 12 volt part and compressor operates on 12 volt.So direct connect of battery to compressor will let you know if its compressor issue or its wiring issue.

now if the AC head is sending the proper voltage when the AC is turned on/off, the ground is properly checked intact, and you not being able to activate the solenoid for the control valve, I don't see any other reasonable explanation other than the compressor/valve being defective.So get the new compressor exchanged from the shop.

These details and testing will help.

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