FAQ: HVAC Blower motor only works part time, or stays on

on my 95 the ac will always do its thing, but the blower motor only works half the time, any ideas? and by the way, on the 97, the passenger side comfort is always hot unless you adjust it to total cold. but once there you can't change it at all. im lost??
and sometimes i hear a clicking sound in my dash, like a clock. any ideas?
thx guys.
tyler

Not sure on the '95, sorry that hasn't happened on mine?

On the '97, I had the same problem on my '99 and they are the same. There is an actuator behind the glove box that opens and closes to adjust the temp. on the passenger side, actually there is five of them in the system, I found that one stuck and it was always putting heat to the passenger side. There is a 7.5 volt, I think, motor in the actuator that got stuck on mine. I used some batteries and wires taped together and got mine working, and it has been fine ever since. Might be your problem too?

Probably blower control module failure. It's a transistor mounted to a heat sink under the dash, attached to the blower motor. Common problem in our cars. $95 from dealer, $30 from salvage yard. Contact Ed Morad, he may have one in stock.

So it's more common for the blower control module to fail than the blower motor itself, eh? Hmmm...I'll have to check my manual to see how to test these, as my blower motor only sometimes works.

Yes, it's mostly the module that goes. It's a transistor that works like a speed controller, and it makes heat. My guess is, it gets too hot and then fails.

you could replace it, then if it doesnt fix it return the part.
btw they get VERY hot for something thats not insulated under the dash :/ but i've never heard of one catching fire so i guess it's good.

the clicking sound you hear is the mixxer door servo, which contains plastic gears...my guess is its slipping... passenger side is easy to replace.but i recommend a bone yard replacement..dealer wants almost 200 bucks for it.....

usually if the motor resistor is bad...the blower wont run on a certain speed.....try banging on the blower motor housing when its not running..an see if it starts....if it does then my guess would be the motor is crapping out...

Still haven't looked into it much, but it seems to me like the blower motor itself is bad in my case. I can hear it clicking when it does work (doesn't sound like the vent door motors in my case). Is the blower motor under the passenger side kick panel?

It's under the passenger side dash, behind the black plastic cover.

Thanks Aaron, I found it. I was procrastinating until I started to think about how horrible it'd be to not have a windshield defroster this winter!

If I grab onto the "knob" that sticks down and push/pull in one direction, the fan kicks in the way it's supposed to. I tightened the screws down that holds the blower motor in place, and at least it works a little now. But it still doesn't work at full capacity unless I push/pull it by hand. Trying to figure out if that means there is a connection problem (wiggled the wires around with no effect) or a problem internal to the blower motor (perhaps something in the electric motor itself), or something completely different. Regardless, it doesn't appear to be a problem with the blower control module, as it has been with others here. Hmmm....

Well, I bought a used blower motor and put it in. So far so good!

the clicking noise could be the squirle cage in the blower motor, and the risiter controls the speeds on the dash for the fan that would not make a clicking.

I'm pretty sure the bearing was going bad in the old unit. Hard to say for sure, but when I put the newer unit in, it worked without a problem. Of course, since I hit a deer the next morning, I guess it's a moot point.

I have been having problems on my 96 where the blower will not blow any air then again sometimes it would. Well, today it quite and will not come on. What should I be looking to be suspect? Blower motor, electronic control module on the dash or???????

Thanks

I'd start with the blower control module. It's a large transistor with metal fins located under the dash near the blower motor.

They are $100, but I found a used one for $30, which fixed my problem.

I pulled the car inside and had a look a few minutes ago. I checked all the fuses first and all was well. Then I pulled the plastic cover under the passenger side to access the blower motor. I then went to pull the connector and presto the blower starts blowing. I wiggle it around somemore and she seems to be intermittent. So I pulled the connector out of the blower motor and pulled each wire out of the connector and squeezed the terminal of each wire together to make better contact. All seems to be good now. Good thing because it's supposed to be -15F tomorrow morning. Shwee, I thought I was going to have to buy that control module but I guess not.

Mine used to go on and off randomly until I fixed it. Hope yours continues to work properly.

My AC works but was told the blower control module needs to be replaced. Could I replace the blower control module easily, without a lift?
I've been quoted $450 by a gas station mechanic.
I called Delco, found out the part is about $82 and takes 1/2 hour to put in. Hey, I may be a woman, but I'm not stupid. I intend to buy a Haynes Manual for my Riv and do simple things myself.
By the way, looked on Haynes and there doesn't seem to be a Haynes Buick 1995 Riv manual. Maybe I'll find it on Ebay.

Does the fan turn on and off when you turn the AC on and off? If it does then I don't think you need to replace it, but I think its on the firewall somewhere and should be quite easy to replace....$450.00 bucks is crazy.

You do this from the interior, laying on the floor under the passenger dash. The blower control module is mounted next to the blower. Took me an hour to replace, cost $30 used from a scrap yard.

Good luck!

Where exactly would I find this blower control module? I can not see anything that loks like a heat sink, there is control of some sort going into heater housing, but I can't find any socket to fit the screws. (6mm too big and 5mm too small)

AA, is this what the blower control module looks like for the riv?



I dont see any heatsinks, and it looks nothing like this one for the regal

This is what mine looked like. The heatsink is the big extruded metal part with fins:

when looking under the dash, do you only see the black part where the wires connect? In other words, is the heatseak not visible until you pull out the module?

here is what I see under the passenger dash. The blower motor is pretty obvious, the large brass circular thing. To the bottom left of it is a wiring harness. Is that connecting to the blower motor control module?

BTW, my blower isn't working at all anymore. After reading my other thread, Is this still the culprit in your opinion?

I think what happens, when the blower motor fails it ruins the control module/resistor at the same time, sometimes.
When the blower motor on my 2000 Regal failed I could remove it and tinker with it and reinstall it and get it to work intermittently. I finally replaced the blower motor and the control/module/resistor....

I hope I am not confusing everyone. I am not sure of the proper terminology for the part. It is the part AA posted a pic of and is located up under the dash near the blower motor.

Bert