: Blower motor problems?



C-Rad
08-09-04, 12:18 PM
I posted this in the DeVille forum, but I didn't get any responses...

On a '69 DeVille...

Q. Should I be getting 12V at my blower relay with the key off?

Q. My blower motor starts whenever I turn the key on acc, regardless of what the internal controls are set to (vent,off,low,high,etc). Is this right? I've read that the blower motor should turn on to a "fixed low" setting when the controls are set to "vent" but I was under the impression that the blower motor would stop if the controls were set to "off". Oh...also, the motor stays at the same speed regardless of what the controls are set at.

Q. Something is draining my battery. Anybody think one of the things above is causing it? I ordered a new blower relay just in case.

Thanks!

wurstarme
08-09-04, 03:32 PM
Regarding your second question: My 1974 DeVille does the same thing. When the acc is on, the blower motor gets turned on to a low setting. I'm interested in finding out if this is right as well..

JacobEldorado
08-09-04, 05:33 PM
The blower motor is supposed to be running even while the controller is set to off, at least that's what my service manual says for my 77 Eldorado. It was designed to constantly bring in fresh air, I think it's a silly feature. I've found in my car if you slightly adjust the switch to the right of "off", the fan turns off compltely.

As far ras the battery draining, I've heard sometimes the seatbelts can drain power, since some of them have some sort of electric saftey solenoid in the base. You might want to disconnect it if your car has one.

barge master
08-09-04, 08:46 PM
The blower is usually running constantly on every GM car with A/C that I've ever seen. It ought to work with the ignition on, but not with the key turned all the way back to ACC. Are you sure that draw isn't your trunk or glove box light on? If you see a little spark when you hook up the battery, try pulling a fuse at a time till you don't get the spark anymore. That should be the circuit to suspect.

davesdeville
08-09-04, 09:03 PM
The easiest way to narrow down a power drain is to hook a light bulb between the positive connection on the battery to the connection that usually goes there. Then pull fuses until the light goes out.

C-Rad
08-10-04, 12:07 AM
The easiest way to narrow down a power drain is to hook a light bulb between the positive connection on the battery to the connection that usually goes there. Then pull fuses until the light goes out.

That's a good tip. I'll give it a shot - thanks.

I do hear a "clunk" coming from the blower relay every time I touch the negative cable to the negative post. This is what is leading me to believe it is something in the blower system - that and the fact that I get 12V there without the key being in the ignition. Anyone know if that's supposed to be like that?

barge master
08-10-04, 05:05 AM
So the relay is engaged whenever the battery is connected? That doesn't sound right. There may be hot power there to run the blower, but the power to engage the relay shouldn't be continuous.

C-Rad
08-11-04, 06:05 PM
Welp...it's not the blower relay. I got a used replacement and it does the same thing. Also the blower motor still runs at the same speed regardless of the switch position. The A/C clutch does engage when the switch is set to "High". When I get a chance I'm going to proof the wiring from the switch and also possibly replace the blower motor (trying to kill 2 birds w/ one stone).

barge master
08-12-04, 07:33 AM
It might be worth a look at the blower resistor and see if the coils in it are degraded. 12v goes into it, and the slower the switch calls for the motor to go, the more of the coils the power will run through. If you probed the terminals at the resistor, you could get an idea of what fan speed the controller is calling for in a given position.