Blowers, part deux

Blowers have once again fried their speed controls, could be that one had been gone for a while due to weakass pressure of late.
So time to take them out again, well actually I never did take out the passenger side unit as it seemed to work ok once I reflowed the fuseboxes.
Of course all this tinkering was in the past, maybe 10 years ago.This time I will be removing both blowers and in order to do the passenger blower I have to take out the airbag. I more than likely will leave it out too.
Anyway, last time I repaired the speed control circuitry I replaced all the components, caps, resistors and the big transistor.
Here’s the question …is it enough to just change the darlington transistor or do I do the whole shebang again?

I have 2 spare blowers but only the passenger side spare responds to the speed switch, drivers side spare just blows high or nothing. Even though the passenger side spare is OK at the moment I’m thinking of putting new transistors in both spares.

One more thing - with the drivers side blower out, would I have access to the upper blend door motor and or mechanism? (the upper blend door is stuck in the cooling position, lower blend door working properly)

Larry, it’s hard to tell if only the Darlington transistor will solve your problem. My passenger blower quit working almost a year ago and I replaced it but it didn’t solve my non working blower. I wish we could get the male and female connectors and make a 2-3 feet long extension cable so we don’t have to wrestle the blowers in just to test them.

Joe, both my spare blowers ran when I sat them in the foot wells hooked them up to the car’s connectors, so I’m going to re-do the transistor stuff in those two and put them in pulling the others out.
That passenger side connector was really hidden though, had to pull the body module and remove the mounting plate just to do the test.

Intended to test both with connection on easy accessible driver’s side but of course the white connectors were different so I couldn’t!

With your passenger side blower …do you have power coming from the fuse box on the brown/blue tracer wire? I’m sure you’ve checked that but I ask just in case!

Ok, let us know if changing the transistors works.
I haven’t checked those wires for power but will do. Thanks.

That wire should have 12v on it ign on or off so all the time. No power = cracked joint at fusebox

Thank you Larry. My volt meter isn’t working properly so I’m gonna visually inspect the fuse box. I don’t remember if I did both boxes or just the left side. Will let you know.

Just get a test light, probe the connector at the blower, that’s what I did

Good advice Larry, thanks.

Replaced the driver’s side transistors etc in my spare blower then installed it in place of the original. Original L & R units are in good shape, just need transistors replaced.

Apart from the missing defrost flap (!) I now have a working climate control again. Just in time too as the weather has turned earlier this year.

BTW, the electronic supplier sent the wrong resistors, 0.25 watt instead of 2.5 watt, so I just left the old ones in. I had the diodes so I did swap them …but I think they were probably OK as well.
When these speed control circuits die, I think 99% of the time it’s just the transistor that fails.
On the driver’s side, access to the two blower mounting bolts is fine, no problem with an extension on a 10mm socket.
I found the hardest part of the job was re-fitting the silicone sleeve between the CCU and the blower. I’d removed it completely to clean out some of the silt around the base of the evaporator - didn’t get it all, but some did come out.
If I was to go in there again, I’d pull the footwell carpeting out and run a water hose into the cavity - there’s a pretty good chance you could wash away all the degraded foam and silt around the base of the evap. Bit of a clean-up afterwards, but with the drain tubes clear, a baling bucket, sponges and towels on hand, not too bad.
Of course, if your footwell is full of rust holes, cleanup would be far less work :laughing: