ling427ttvette

iTrader: (1)

Well, right before I bought my car the heater fan would not work on high. The previous owner fixed that, but it didn't last very long. It quit working on high after a while.

After a while longer, the fan just started randomly working. It would only work when the engine reached a certain RPM, usually around 3000RPM or so, and it would shut off once the RPM's dropped so low..

And now, it just does not work at all. I can turn it to heater, turn the heat up, turn the fan up, and all I get is a hissing noise... some kind of vacuum leak from behind the HVAC controls. When I was replacing my console I took a small look at the lines and stuff behind there and nothing, I un-plugged the main vacuum line and started my car, it has vacuum. There is no vacuum leak when all of the controls are off though.

I don't understand how a vacuum leak would cause the fan to not work though. What are some things I should look for?

19RS92

The vacuum only controls the ducting inside the dash (floor, defrost, vent). The blower motor is only controlled by electricity, the blower switch. If the fan only ran on low and medium, then randomly i would say the fan motor is bad. Turn the car on, turn the heater on with the blower switch in "high" position and test the motor using a simple test light. If there is no power to the motor the blower switch is probalby bad. If there is power to the motor and it does not run the motor is bad. Try tapping on the motor case and see if it starts to run, if it does replace it.

ling427ttvette

iTrader: (1)

Well, I went out and looked at it.

I checked the wires straight into the motor, it sporadically gets power, and the relay is clicking on and off. So, I went to O'reilly's and they had to freaking order the relay.

Anyways, this should solve the problem, if not this will be a start anyway.

bobdole369

If a relay is clicking theres a good chance it srill works. Redo the wires going TO that relay as they are the more likely cause. Also just fyi, on low and medium it goes through a load resistor. on high it simply puts all 12 volts into the fan. Not 100% on an 83 camaro, but on my 89 bird there is a connection near the firewall that went bad and got awfully corroded. This was the 12v line to the blower motor.

19RS92

If the relay is clicking it is doing its job. It gets its power from the fuse and the blower switch is what triggers it (makes it click). I still think you have a bad blower switch.

ling427ttvette

iTrader: (1)

Yeah, I almost think that the relay is still good.. because today and last night the fan was blowing.. I had it on high and it wasn't blowing that well, but it was blowing heat, thank god.

So, I will put a new relay in and I guess replace the switch as well. How do I do the switch, it's all tied in with the HVAC unit isn't it? Or does it come off seperately?

sofakingdom

iTrader: (1)

https://www.thirdgen.org/forums/tech...no-longer.html

JamesC

iTrader: (5)

Hey, Sofa,

Got that link bookmarked yet ? If not, you need to.

JamesC

locutus918

if you take 12 volts and put directly to motor from battery this should test the motor correct?

hitman0187

this thread is 4+ years old, but yes that should test the motor. Do you know where its located?