I have a 1993 Ford Escort 1.9 LX Wagon. The Electric fan stopped coming on ages ago. I have to keep an eye on the temp gauge and turn the fan **** and air on to get the electric fan to kick in. Took it to a mechanic who tested and ruled out anything under the hood. He said it was likely the ECM inside the car, passenger side, near the floor. The guy wants $200 just to replace the computer and he's not positive it is the problem.
I've looked at the ECM unit, it appears to be just a bolt in the middle to hold the cable connector in and some side clamps. If I bought a used or re manufactured ECM, could I just disconnect the battery, pull the old unit out and replace it??? I have read that starting in 1996, the modules are programmable and my fear is I yank this puppy out and the car won't start, even if I put the original back in.
Oldie but goodie, just 93K on it (previous owner bought it new for his wife then never let her drive it, they had to take his car).
Would like to keep it, help would be appreciated. The car also has NO power accelerating up hills. I think catalytic converter, the mechanic thinks it might also be tied to the bad ECM. Please advise.

 

Some things you can try,
If you hook a vacuum gauge to any vacuum source on the intake manifold you should with the engine running get around 17-18 in vacuum at idle. Then raise engine RPM up to approx 2000 RPM if vacuum goes down steadily , there is a restriction in the exhaust system, possibly converter.
If that checks out OK, you can swap ECM units without any problem as long as it came from same type vehicle, same engine etc.
Don't remember if the vehicle had 1 or 2 cooling fans. If only one fan motor and it works when A/C is requested chances are the relay & fan motor is OK. Coolant sensor sends temp info to ECM and ECM sends signal to relays etc. Looking at the wiring diagram the two relays for the cooling fans on the L/F fender apron appear to be the same and there is a good possibility one of them is defective.

 

Thanks Hanky: There is only one fan and the mechanic said that he checked the relays on the L/F fender apron. I'm don't work on cars beyond maybe an oil change, filters, etc., so I don't have a vacuum gauge to do what you suggested. From your reply it sounds like I could be getting myself into trouble if I just switched out one F3CF-12A650-KB for another F3CF-12A650-KB (number under bar code). Is that correct, there is a chance I could end up with a car that doesn't start or ECM with no data and won't relearn it in 50 plus+ miles???

 

You should not have any trouble starting the car if you switch fan control relays. If the vehicle were say 99 and up even then as long as the relays are the same # does not create a problem. When you remove power to the ECM either by removing the ECM fuse or disconnecting the battery your model year only loses it's KAM (keep alive memory) and it relearns that with one or two short trips. It usually also erases any codes in the computer. Newer vehicles are much different and things you can do with your vehicle you cannot do with newer ones.

 

Many thanks Hanky. That answers my concern. Appreciate the help.