I've been trying to fix a problem with the ECC fan in my '94 964 for a few months now. The problem started one misty day when I was driving the car and the fan just quit. I thought the fan had finally kicked the bucket (had been making a little squeek when it stopped). So, I put in a good fan out of an '88 765. That didn't work and that's when I realized the 30A fuse for the fan was blown (oops). So, I replaced the fuse and the everything was fine.....For about 2 minutes. Every time I put a new fuse in and turn the fan on, the fuse blows (with an noticeable snap) in about 2-5 seconds. I tried replacing the ECC control unit (dials) with one out of the same 765; Nothing changed. So, I looked up the wiring diagram (http://caunter.ca/volvo960/xg14802.pdf) and went from there. I looked next at the "ECC Power Unit" and surrounding wiring. I discovered a wire (pink/white) that had been repaired at some point and still had a bare spot, so I covered the bare spot with electrical tape; No luck. Next I tried disconnecting the fan from the ECC Power Unit; Still no luck. The fuse still blew with the fan turned on at the dial, but without the actual fan connected. Therefore I unplugged the ECC Power Unit; Then the fuse didn't blow. That brings me to today when I replaced the Power Unit with another out of a '93 965 (what a pain to replace!). I plugged in the new power unit and, after the fan being on for ~5 seconds.....POP goes the fuse. I felt like driving the car off a cliff!!! AGH! One thing I've noticed is that when the fan dial is at "0" and I install a new fuse, I get a spark at the fuse plug and the fan comes on briefly. I don't know why the fan would come on with the dial set to 0. Anyway, I am SO open to suggestions. I'd really not like to take it to a shop and spend a ton of money looking for this problem. In fact, I'm not even sure where I would take it as my mechanic has already looked at it once and I can't think of any other Volvo mechanics in the area who I think would be able to solve this problem. I don't think our local Volvo dealer would have much luck with it either as they mostly service newer Volvos. So, ANY HELP would be VERY MUCH appreciated!
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Chris. Halifax N.S. '98 V90 > 198K km, '94 964 > 90K mi. SOLD: '91 745T and '91 745 NA (I miss both of them!).