hi, my 2002 hse has a problem with the a/c. It starts out fine and real cold and and as soon as the cab reaches right temp the compressor I think doesnt cycle back on,and yes to stupid book symbol appears. My a/c guy said its got enough refrigerant he emptied it once and measured and said it was right were it should be he thinks the compressor clutch might be going bad he suggests tapping it with a stud to see if it starts doing it again. (it wont quit cycling on when he checks it out)any ideas of what else it might be.

 

Well, The first thing you need to do is pop the hood when it does it and see if the compressor is turning. If not, then tap it with something to see if it engages. Be careful. If it does, you probably just need to remove a shim from the clutch or you may need a new clutch as your mechanic said. Another issue could be improper voltage to the clutch. Easy enough to check with a volt meter. Another could be a bad relay that engages the clutch. Try swapping it out. If the compressor is turning, my guess is that the sensor inside the vehicle that controls the temp is bad. Hope that helps you out. My guess is that it is the relay.

 

thanks, wilson 96. I'll pass that on to my ac mechanic, sound very logical. I love this forum and and good contributors like you. bobco

 

The clutch like wilson stated, is known for going out due to age and use. When you are diagnosing this, do not use the "AUTO" function on the HVAC controls. Ensure that the "a/c off" light is not illuminated and set both temp zones to "lo". There is the possibility that your 3 way pressure switch is going bad. Basically, if the compressor is getting the correct voltages, it is most likely the clutch. If it is no longer getting any voltages, it is probably the 3 way pressure switch. There is the possibility the HVAC ecu/control panel is going bad, but I doubt it.

 

How about checking the codes in the HVAC system. If you ac mechanic was so smart that would be the first thing he would have done.

 

I think you need Testbook or equivalent to check HVAC codes.

 

Yes you do the code readers wont read those codes unless you get the big money one from AB