fastbackford351

So I'm driving back from Daytona Beach yesterday in the '02 GT with the AC set to 'snow' and everything was jiggy until I got too chilly and turned the temperature **** from 'snow' to 'just nice and cool'.

With the AC still set on maximum I turned the temperature control **** down just a bit and splat, the AC quit working altogether. Still blowing to beat the band but no cold air.

What happened? What should I check? Summer is here and the temps are hitting 90 and I needs my AC.

Thank you in advance for the counsel.

cliffyk

Check all the fuses related to the AC, you can download an Owner's Manual here, and if they all check out then make sure the AC clutch is pulling in when you turn the AC to MAX.

If it is not then it could be:

• A bad control switch (AC Cycling and/or Pressure Cutoff), or;
  
  
• The A/C Clutch relay (in the CCRM) has failed, or;
  
  
• The refrigerant level fell below a critical point at which the control system will not allow the compressor to run, or;

If it does engage then it could be:

• The vacuum selector valve, one or more vacuum motors (there are three) has failed, or a motor linkage arm has failed, or;
  
  
• The cable that runs from the temperature **** to the air mixing door, however if that had broken it should be blowing HOT air not just not-cooled air;

I'm sure I've left something out, but that's what came off the top of my head.


To check he refrigerant level you will need an R134a gauge and manifold set;



It will cost $55 (Harbor Freight) to $100-$150+ (Sears, most FLAPS, etc.) depending on where you buy--it's one of those things that are pretty much all the same functionally, spending more will get you a higher mechanical quality set, better connectors, etc.

Haynes has a pretty good Automotive HVAC "techbook", available at most FLAPS, that will get you up to speed on how auto AC works, and troubleshooting tips...

cliffyk

The OP sent me an email stating that the clutch is not engaging--so what needs to be done next is:

• Check fuses #2 (20A), #23 (15A) and #24 (20A) in the Central Junction box;
  
  
• Check the refrigerant level as discussed above, obviously check for leaks as well;
  
  
• Check for +12V between ground and the violet and dark blue/yellow wires at the AC Cycling switch (RH side, rear near firewall) with the AC On, if +12V is not observed the cycling switch is bad;
  
  
• Check for 0.0V between ground and the tan/light green wire at the AC Pressure switch (RH side, front near radiator) with the AC On, if 0.0V is not observed the pressure switch is bad;
  
  
• Check for +12V between ground and the black/yellow wire at the clutch coil, if +12V is not observed the clutch relay in the CCRM is bad, otherwise the clutch coil is likely bad;

Note that both the cycling and pressure switches screw on to Schrader valves and can be removed/replaced without depressurizing the system.

fastbackford351

Cliffy thanks for the information. After trouble shooting it turned out that it was the CCRM.


R&R'd said module and now my nipplulars are frosty once again.


Thank you.