AC cooling fan wiring problem

[Stuart]

(Last post got dumped, re-trying)

I discovered that my condensor cooling fan was not comming on when the compressor clutch engadged. (tested fan, it works) I traced the problem to what looked like a proken wire (Red wire) so I tried to add a jumper wire (Blue), but I connected it ground instead and blew the "in-line fuse" (green loop).

Now, where in the car is the in-line fuse located????

Pict from Haynes Repair Manual PN: 36030, Page 12-39

For those that followed the "Dirty car Picture", same car, engine re-build (Finally!!) now, just fixing the 'little' problems so that the car is now like new...

[FB71]

the condensor fan does not come on with the compressor clutch. It's controlled by a pressure switch on the liquid line, up near the passenger strut tower. The condensor fan only runs when the liquid line pressure is high (above 200psi or so).

[FB71]

the fuse you are looking for is under the dash, driver's side, near the heater box usually. I have also seen them on the passenger side, also near the heater. Its a white plastic fuse case with a glass AGC fuse, often wrapped in foam to prevent rattling.

[Stuart]

OK, found that fuse under the stearing wheel, it is good. (I drew that one on my wiring diagram.)
My wiring dragram did not look like it agreed with what I saw under the hood. That could be why the condensor fan was not comming on when the clutch engerized, differance in car years.

The problem is that I no longer get 12 to the compressor clutch. that is the fuse I'm looking for. And relay #2 no-longer switches. (the one that powers the clutch.)

BTW, I have a 93 festiva...

[fastivaca]

The compressor clutch needs a couple of things to happen before it engages. First there has to be the correct pressure in the system and secondly the heater fan has to be turned on.

Hope that helps.

[Stuart]

OK, found the other fuse, it was next to the first one...
Unfortunally... the fuse was good...

And yes, main power on (engine running), inside fan on, push ac button...
I did have the clutch comming on, but the condensor fan did not come on like the prints said it should.

Yes FB71, after looking closely, the pressure switch controls the condensor fan.
But, when I did the jumper, I killed something, but not the fuse...
Dad worked on it today, but could not find the problem.
( I had a road trip needed to be done.)

I'll give what I find tomorrow...

(If the troubleshooting was not started, I think everything would have fine...)
But, oh well....

[Stuart]

OK, I've now got it tracked down to the last item... the electronic control assembly... aka the ECM, AKA: the computer...
I have an electronics background so I removed and opened the computer a found a blown resistor, but, because it is burned, I can't find out what it's resistance should be...
The computer is out of a 93 festiva and the ID# is B376 18 881D
The resistor is R852, brown 1/4 or 1/8 watt.
If anyone has a computer that is out of a car, could you open up yours and see if you can find any numbers in it, please???

[Stuart]

OK, alternative plan...
I could hot-wire the relay control to a switch and just turn on and off the clutch my self, but...
Does anyone know of any dangers involved with having the compressor engaged for extended time???
My parts guy commented that on cars with "max AC" the compressor is always engaged.

I was thinking of re-wiring the AC switch for this so that there is no extra switches visible...

[skimsucka]

theres a car here in the junkyard with a computer if you want to give me 15$ on top of what yard charges for it ill go get it and ship it to you . its not a good idea to start rewiring things yourself lol let me kno

[Stuart]

I already got the re-wiring done, from what I can tell from the engine, it does cycle.
$15 pluss yard rate, check on it please, I may be in the market for a back-up.
If I did kill the computer so that the car was dead, I would jump on that right away, but just for the AC...
From what I have noticed, dead festivas are being scrapped quickly...