A Tangled Web of A/C Problems

[ssmlauck]

1999 V70XC AWD

This one has me totally stumped and I could really use some help. At this point I'm ready to turn it over to "The Volvo Whisperer" but every time I visit him I wind up broke for three months. Here's what I've got:

I was having standard blower motor/resistor symptoms (running on high all the time, intermittent blowing, etc.) and then the blower quit working altogether. I replaced the motor but NOT the resistor. The first time I tested the new blower motor it worked fine but I still had only a HIGH fan, regardless of what speed I selected. So I ordered a new resistor and changed that out too. The new resistor is OEM, but there is a slight variation in some of the other numbers (The old one reads 9166694 followed by 98W45, and the new one is 9166694 - 09W39V) so I don't know if there have been subtle changes from year to year.

In any event, the blower would not come on at all with the new resistor, the recirculate and ON lights blink together, and the #31 fuse kept blowing. I decided maybe the new resistor was faulty and reinstalled the old one. Now I am having all the same problems with the old resistor (blower won't come on, blinking lights) and although the #31 fuse is not blown completely, there is a lot of pitting and stuff on it, like it was about to go. This was after turning the system on for about 1 minute.

With both the new and old resistors installed I can hear a slight hissing, like the compressor is trying to start or the system is releasing coolant?

Any ideas or do I head off to Super-Mechanic's tomorrow?

Thanks.

[Ozark Lee]

Do you have the ECC or the MCC? My guess is that you have the MCC since you describe speed 4 as working.

They look very similar but the MCC has 0-4 on the fan scale whereas the ECC has no such graduations.

Does anything say AUT?

If we determine that you have the MCC then it means that you smoked the blower resistor since it works on speed 4 and you replaced the blower motor.

Someone remind me to do this on my daughter's S-70 soon before I need to buy a new power stage for her ECC since she told me yesterday that the fan is screeching badly.

I can lube up the blower motor and buy a year or so but once it (the blower motor) seizes, either on the MCC or the ECC, it will eat the blower resistor or the power stage every time.

...Lee



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[ssmlauck]

Lee,

Thanks for the reply. Sorry I didn't include it in my original post, but it's an ECC (AUT at one end and then a nice little sliding bar up to high). The main thing that concerns me now is that the blower motor won't come on with either the new OR the old resistor in there and it keeps blowing those fuses. Originally, I replaced only the blower motor and although the new one came on, I still had only high speed, regardless of where I put the sliding bar. It's only since I started messing with the resistor that the whole thing has gone to s***. Maybe I should have just left the old resistor and let it burn up the blower motor again...I probably could have gotten at least a few months out of it.

Anyway, if you've got any clues, I'd definitely appreciate hearing them. I was starting to get worried with all the views of my post but ZERO replies. In MVS lingo, does that translate to "just burn it"?

[Ozark Lee]

Ground the blue wire to the blower and see what happens. You can do it key off with the power stage (blower resistor) unplugged and the blower should run full blast. If it blows the fuse again then you likely have a bad blower - if it does run full blast you have a bad power stage.

What size fuse are you installing?

...Lee

[ssmlauck]

I'm installing a 25A fuse, which was the size listed on the fuse box cover. Should I experiment with something different?

Thanks.

[Ozark Lee]

Actually fuse 5 should be a 30 amp but if it is blowing it instantly that is not the issue.

Remove the lower dash panel and try the grounding trick.

...Lee