defrost/fan stopped working

[dughrt]

Looked around and couldnt find the answer so I am looking for ideas on what happened. Defroster worked great last wed. but this morning when I went to drive my 84 brat to work the heater/fan never worked. I couldnt get the windshield to defog and had no heat. I played with the fan knob but it made no differance. I checked the fuses and everything was ok so what else should I try before taking apart the dash looking to solve this problem?

[Txakura]

deleted

Edited January 5, 2010 by Txakura
mis spoke, dont know brats

[backcountrycrui]

Not sure if it the same on brats. But on GL there are fan control resisters behind the heater fan, mounted into the same plenium that the fan is mounted in. On my 86 ther is a couple of cracks in the white colored clue on the resister wires. It still works great. On my 90 however there is two coils that have melted away. So only fan speed 3 and 4 work on that car. Hope it helps

Mike

[Cougar]

I take it that the blower isn't working at any speed. Which may mean the thermo protector in the resistor block may be open. When some of the speeds don't work it is usually due to open resistor coils. Either way the block needs to be replaced. Another possible area of trouble is the blower relay. By using a test light probe to check for power at the blower you can see if the relay is working or not. If you do have power then the relay is ok and the resistor pack is most likely bad. You can also apply power directly to the motor to see if it is bad.

Edited January 5, 2010 by Cougar

[Txakura]

^^^ exactly

 

without knowing a darn thing about the brat, see if power is at the fan, pull the resistor block

 

it's odd that all three of them would have broken at once, but they are pretty fragile when they get old

[robm]

My bet is on the blower relay. If it was the resistor block, it should still work on high speed.

 

What fusible link feeds the blower on the Brat? Could it fail without shutting down something else?

[Frank B]

If you check all the things mentioned above, and it still does not work, open up the motor and check the brushes. You may be able to find some at the parts store that will fit with a little filing(they are very soft). I used brushes out of a vacuum cleaner motor once .

Best way to eliminate all the other stuff is check for voltage at the motor plug.

[dughrt]

Ok wierdest thing. It worked today.

I started the Brat and nothing. So I took the tray out from under the glove box and found the vent tubing. I disconected that and then started the car and turned on the fan again. This time it worked. So I left it on and put the car back together. Hopefully it will still work in the morning.

Is it possible that a vacume leak had something to do with this?

I had a hose unplugged under the air cleaner and the brat wanted to die at idle. Plugging that back in is the only thing I did on purpose.

Thanks for the ideas guys.

[ivantruckman]

Ok wierdest thing. It worked today.

I started the Brat and nothing. So I took the tray out from under the glove box and found the vent tubing. I disconected that and then started the car and turned on the fan again. This time it worked. So I left it on and put the car back together. Hopefully it will still work in the morning.

Is it possible that a vacume leak had something to do with this?

I had a hose unplugged under the air cleaner and the brat wanted to die at idle. Plugging that back in is the only thing I did on purpose.

Thanks for the ideas guys.

 

 

 

Its gotta be the relay, the contacts can be corroded or burnt, my fan worked intermittently before it died, it was the relay