RogerC:
The A/C is turned on in the following four HVAC modes: Max A/C, Norm A/C, Mix and Defrost.
There are 2 circuits that control the fans:
1 - The PCM controls them when the A/C is either off or on and turns them on at either low or high speed, when needed, depending on engine temp.
2 - With the A/C on, there is a multistage pressure switch in the A/C system that turns the fans on at high speed, independently of the PCM, when the high pressure side of the A/C reaches 285-315 psi and then turns them off when it drops to 220-280 psi. Additionally, that same switch will disable the compressor clutch if the A/C high side pressure reaches 415-445 psi and re-enable it when the pressure drops to 220-280 psi <-- high-limit safety switch.
If you lose your fans, initially the A/C clutch will engage and run until the high limit switch senses an over-pressure condition, when it will turn the A/C clutch off. The A/C will cycle a few times like this until the system gets really hot and then it will stay off for quite a while, hence, no A/C. If you're driving at hwy speeds, there may be enough air flowing through the condenser to keep the pressure low enough to allow the A/C to run, but not usually on very hot days. You may also have engine overheating problems at standing idle or in stop & go traffic. (these were the symptoms on my car)
The problem with the fans is, that over time the bearings tend to sieze, the fans bog down or stall and draw a huge amount of current. If the electronic circuit protector recall (program 00M13, 8 yrs / 100K miles) hasn't been done, you can fry the fan/main wiring harness(es) OR hopefully, blow the 60 amp cooling fan fuse before the harness gets burnt up. Mine blew the 60 amp fuse even though the recall had been done.
So,
1) Check to see if the A/C works for a while before the car warms up. The fans should come on shortly after the A/C is turned on and maybe cycle every 1/2 to 1 minute.
2) If they don't run, check the 60 amp fan fuse in the fuse box (the middle one of the three biggies in there and it is a PITA to replace).
3) With the battery
DISCONNECTED for safety, turn the fan blades by hand to see if they turn fairly easily. If one or both seem very stiff or are siezed, you need to replace the fan assy (~$235 from fordpartsonline.com and not a fun job).
See:
Cooling fan replacement procedure for the agony
(thanks to projectSHO89).
If one of the fans still seems to have good bearings, you can disconnect the bad one (disconnect and save the electronic protection module, if the recall was done) and try to temporarily run on only one fan until you can replace the whole assy (may not work). The electronic protection modules from the recall are located in-line, at the connectors of the fan motors and are weird looking things about 4" long. If the 60 amp fan fuse is blown, you'll oviously need to replace it.
If the above suggestions don't pan out, I don't know what else to say except you've got other problems and prolly need the services of a dealer or knowledgable mechanic.
Kurt
