2002 jetta-turn on a/c.Compressor &fans do not engage,person diagnosed as comfort control module,could this be correct?
Year : 2002
Make : Volkswagen
turning on a/c to see compressor does not engage. Then had it checked,and was told system was charged,but as soon as it is turned on the comfort module kicks it off.
NO comfort control unit can not control A/C function. Most likely is one, low freon, two power supply to fan control unit, check fuses on top of battery, three ambient temp sensor bad or has rodent damage to the wiring, located under the cowl on the passenger side. A bad fan resistor can also cause this.
David,unfortunately I did change the module(though used),the fans now operate.You can here the system clicking (rpm change),but the clutch on the compressor is not kicking in.The mechanic that diagnosed the module said the system had enough freon.How would I check the compressor operation? (it has a 2 wire lead)
Check voltage to the compressor, the brown is ground the other is power. It may only have 9 volts. It uses 12 to engage and less to hold. You can make a temp conector and apply voltage to the clutch. If it comes on then it is not likely the compressor. Use caution and make sure there is a fuse so you dont burn something should the clutch be bad. Also it is possible that the pressure switch is bad, here is the dumb catch the only way to test this is to put another switch in its place. At the dealer we always had a good used on in our box. One more item to check, under the cowl on the passenger side is an ambient temp switch, two wire. Common to have rodents eat or chew the wire going to this, if it is open shorted, the compressor will not turn on.
VW Master Technician Certified for 9 years, ASE Master Technician Certified
David,thanks for your patience,I could not locate (ats) though I did clean a mouse nest out from on top of cabin filter in cowl area.I also unplugged compressor,wired direct to battery,but no response from compressor.Could ambient temp sensor be located elsewhere?
The ats is under the cowl next to the pollen filter or on the left side by the fender both under the cowl