Xliberater

Hey everybody my blower motor stopped working recently in my 81. It does not work on any setting (high, low, medium fan speed). This is an a/c car and the blower will not turn on with the controls set to either a/c or heat.

I started with the basics by checking the fuses and it looked good. I checked the ground wire on the blower and cleaned it up with no luck. I checked the voltage at the positive wire as well and it is getting 11-12v. However, when I jumped a wire from the alternator to the blower it started right up. Why would it run when it is jumped but not when the power wire in connected even though it has voltage?

Where should I start looking next? Thnx guys

MSGT-R

Go to where the blower housing where the plug for the resistors are. You should have power there. If you do, the resistor -pack is burned out. two screws and it should come out of the housing.

Here is a generic picture so you get the idea:



Most GMs operate the same.

lvmyvt76

check the ground to the fan motor, everything needs a ground on a plastic car.

0Willcox Corvette

Well it could be a issue with the armature in the blower motor. A burnt spot..

You have power and ground to the motor, there is no reason shouldn't work unless there is a corrosion or contact problem in either the ground or power terminal. Check all the connectors

But what is odd is that you have two circuits on the blower motor...
Hi side, which is direct power, then all the other speeds through the relay.
For it to not work on both is unusual and about the only thing that will take both out is the control switch on the heater control and a ground. This kind of pushes me toward a ground issue. Make sure the ground terminal is clean on the motor.

Are you sure the fuse is good?? With the fuse in place, test the passenger of the fuse for power.. I'd pull it and make sure it's making good contact in the panel and look for corrosion there as well.

If you look at the schematic below, you'll see the brown from the fuse panel goes to the control switch. The power then runs for the control switch on the yellow to the blower switch...

MSGT-R

Nice diagram, Wilcox!!

Xliberater

I tested both the resistor pack and the relay. On the resistor pack I am getting 12v from the brown wire, and about 6.5-8 on the tan and light blue wires (is this normal?). On the relay I am getting 12v from the red, dark blue, and orange wires and about 11v at the purple wire going to the blower. I double checked all the grounds as well and even tried jumping a new ground but it didnt work.

Once again none of my heat/ a/c controls work on ANY setting and the blower never turns on.

Xliberater

update: I decided to check the voltages with a test light for the hell of it and the test light doesnt work on anything except for the red wire on the relay. Even though I have ~11v at the brown wire at the resistor pack why would the test light not work there? Is my voltmeter lying to me?

Xliberater

fixed! turns out I must've kicked something by the fuse panel because there were a few loose connections which I couldnt see at first (they probably could've put that fuse panel in a better place). Now I can drive a little bit cooler.

0Willcox Corvette

good deal 34 here tonight.. not much need for cooler.. heat would be nice.