Blower motor on constantly, even when car is off

Went to start the OCC yesterday (it's off the road for winter; gets started up and driven around block once a month) and the battery was stone dead. I went to jump it and as soon as I hooked power to it the blower fan came on even though the car was key-off. I turned the ignition to on, but the auto climate display just kept counting down from 30 over and over (the battery has never died in this car so I don't know if that count down thing is maybe normal after dead battery?) So I started it up and the climate control seemed normal, but the fan would not respond to any input from the controls; it was just always on, somwhere close to or at full fan speed. I looked on here and the ISSF but coulnd't find anything that seemed to cover what mine was doing specifically, although I found one post for an LT1 RM that was doing it and someone mentioned a "stinky vent" TSB that could have malfunctioned and caused it, but I'm not seeing that TSB for the '92 OCC. The thread cliff-hanged as the orginal poster did not follow up on what caused it, so I'm coming here looking for help. Anyone have any ideas? Oh, one addition detail which may or may not be relevant is my fan motor has been known to make a bearing screech from time to time.

I'm not sure if this applies to a tbi car, but maybe it's the same with climate control. On all of mine I've had to replace the blower motor control module. On 2 cars the fan wouldn't blow at all but on my wife's ldm it did the same thing yours is doing. Even with the car off and the key out it still blew on high.

The module is easy to get to, it's right below the blower under the pass side dash. On the 94 it has 2 plugs and 3 5.5 mm bolts to remove and it drops straight out. Gm is proud of the replacements so I grab all I can from jy's. I also used one from a Park Ave in one of the cars.

Maybe someone else knows if your 92 uses the same part but that sure sounds like your problem.

Jon

I know the blower motors and cage are the same as I put a 96 9c1 unit into the Radio Flyer just after WF last year. I would guess the control module is also the same but don't quote me on that. You have one in your LT1 car so it's ez to check

The 30 second countdown is normal after the battery dies as Big Red has the same climate control and had a crappy battery in it the past few months. Although it'd count down once and then the blower would kick on.

My advise would be swap the control from your other wagon over to see if it fixes it then you know!

I just thought of this - unplug the control and see if the blower shuts off. You can also just plug in another module without taking the old one out to see if that fixes it. I did that in a parking lot this winter and drove home that way until I had time to mount it.

Jon

Yes, it's the blower control module. I had a 91 Cruiser with the same problem. Pulled out the module and found this:
https://2img.net/h/i159.photobucket.com/albums/t136/dbeasst/91cc/bad-bcm.jpg

Replaced it and worked fine. Don't know if the modules are the same between the TBI and LT1 cars, never checked. They ARE, however, different between the auto climate control and manual cars.

Also, yes, the climate control does that count down 'self test' after a battery disconnect.

DBeaSSt wrote:

Yes, it's the blower control module. I had a 91 Cruiser with the same problem. Pulled out the module and found this:
https://2img.net/h/i159.photobucket.com/albums/t136/dbeasst/91cc/bad-bcm.jpg

Replaced it and worked fine. Don't know if the modules are the same between the TBI and LT1 cars, never checked. They ARE, however, different between the auto climate control and manual cars.

Also, yes, the climate control does that count down 'self test' after a battery disconnect.

Ahhh. so i guess the one from my LT1 Caprice won't be able to swap into the OCC to test because the Caprice is manual controls then. I'll have to go junkyarding and get one, hopefully that will be it.

Guess I'll find out tomorrow if the Caddy uses the same module......got home tonight and the motor wouldn't shut off....pulled the fuse and will take the wagon to cruise night...

Wagon 1, Caddy 0

It is the same.

Way to go 90's GM, had this same issue on my '97 S-10 pickup. Blower module fixed it....

If anybody needs one of these, send me a PM. I've got a good tested one here I can send you cheap.