1999 ford escort a/c

[bad andy]

I have a 1999 ford escort wagon w/ a/c problem. a/c clutch will not engage. Jumpered clutch with hot wire and a/c runs and blows cold. High side is about 175. Low side is 45. Have voltage to high and low pressure switches and cooling fan blows when turned on at dash controls. Have a wiring diagram from Hayes book and it shows an a/c cutout from the pcm. Does this car have an a/c full throtle cut out switch? Can't find it on schematic. Fuse under dash is good. Any more relays or switches I might have overlooked? I am stymied!

[sierrap615]

a WOT switch may be built into the TPS(PCM sees above a 4 volt signal or something, the PCM goes into full throttle mode)

did you check for a voltage drop at the a/c clutch?

ohm out the pressure switches?

[bad andy]

Originally Posted by sierrap615

a WOT switch may be built into the TPS(PCM sees above a 4 volt signal or something, the PCM goes into full throttle mode)

did you check for a voltage drop at the a/c clutch?

ohm out the pressure switches?

There is no voltage at the clutch. Ohms across the clutch are negligablable as well as the switches. Wiring diagram shows a blower relay, but I can't locate it! It is not under the hood in the relay box and I don't see it under the dash. All other functions of the heater work. Is this part of the pcm too? I tried disconnecting the battery as well with no sucess. I will replace the TPS and see what that gives me.

[bad andy]

Finally found problem! Bad constant control module. Found one at salvage yard and works fine. Seems to be a problem with Escorts. Lots of them are already pulled. Ford has a new replacement for around $200.00 fyi. Thanks for all your input!