This is a reply to an older thread I was working on here:

https://volvoforums.com/forum/volvo-850-16/climate-control-not-working-odd-light-malfunctions-29097/

Well I finally got around to finding a new resistor motor. Instead of forking out the $140 for a new one, I tried my luck with one from a wrecking yard for replacement parts. Its a gamble yes, but I think given the resistor was only $10, I thought it worth it.

Anyway, I replaced the blower from another 850, and found an identical (I think) resistor from an 1998 S70.

So replacing all these parts, along with a used climate control unit the fan nearly works.

With all the stuff hooked up, all the fuses in and everything here's what happens: When I turn on the car, the blower starts turning for about 1-2 seconds and then turns back off. Testing it with the old fan it does the exact same thing.

So far I've not taken it out for a long drive to see if it comes on after a while or not.

Before this I had heat going, and if I turned the heat up or down on the climate control unit, the car would get heat or no heat correspondingly.
On some occasions the AC off light and off lights (right next to the lower right switches) on the climate unit would blink for a while when I turned the car on.

My question is, do you think this is the blower resistor still or could this climate control unit be faulty as well?

BTW whoever mentioned that the fan had problems was right, pulling the old fan I found it barely moved, compared to the replacement which turned just fine.

Any help would be great, as its starting to get cold out here!

 

Hello, I'm certainly no expert but will share what I went through to get my heat going a few months ago. I just purchased the car so I had no history to go by. First I have auto climate control. When I turned the setting to control fan speed manually, the heater fan would trun for a couple seconds then that was it. I had it removed to verify it. I pulled the codes, then cleared them. The codes indicated a whole bunch of stuff. I determined it was one of 3 things, blower, resistor, or control unit. I replaced the blower with 2 different ones from the junkyard, smae results. Next, I pryed open the resistor (which ruined it) but wanted to see if it was the problem. Indeed, inside was some capacitors that oozed all sort of goey stuff. I ordered a new resistor from FCP. Next, since there were screws holding the control unit together I thought, why not see what it looks like too. So, I opened it up and very quickly seen a large burn mark inside it. It was garbage. I bought a used control unit off the classifieds and replaced it. I had a bad resistor and control unit, which caused which I'll never know, but it works great now. Good luck and hopefully the experts will chime in.