A month or two ago, my blower motor stopped working all of a sudden one REALLY cold night. Started working again shortly after. Quit for good a day or two after that. Ended up replacing the fan control switch that is mounted on the HVAC control head. This fixed the problem, and all has been fine until yesterday.

Fan stopped again....never came back.


Ran a wire directly from the battery, the blower motor fires right up. So the ground is fine. I was getting no power at the blower motor from the interior.

Pulled the radio / and HVAC control head and this is what I find.....




Nice huh?!?


So I pulled the connector off the burnt switch, and found that the connector TO the switch was toasted as well.....At least one terminal in the connector broke free because the connector plastic iteself had burnt through...




Lovely......so I'll keep tracing it back until it's NOT burned up......




There's 3 wires in the picture above. The GREEN wire goes back into the dash harness. The BROWN wire runs into a connector. This connector plugs into the BROWN wire that goes to the fuse panel feed. The BROWN / WHITE wire loops over into the connector that plugs up to the fan speed switch. This connector was burnt as well......See here:



Everything else appears to be fine. So I just plan on grabbing a new switch for it. This is the switch that you move with the top lever on the HVAC control head. Trouble is, after checking around no one stocks one. The AC Delco pt# 15-71113 is valid, but I can't find a local distributor thats open on the weekend around here. So I figure I'll hit the junkyard tomorrow morning. After cross-referencing the AC Delco part number, turns out this switch is VERY popular and used on tons of other GM vehicles, so I shouldn't have a problem finding one.

At the same time, I'll just take the connector for it as well and splice it in to replace my burnt connector.

As for the fan speed switch, I recently replaced it, so it SHOULD be fine...guess we'll see. But the connector to it looks really crappy......not just it's shape, but it's design as well. So I decided I'd make it easy and just get some big insulated female spade connectors and hook them up directly to the back of the speed switch .......seen here:




Funny thing is, before I posted this, I did a search on the boards here. Turns out this has happened before, and this was the solution used. No such thing as an original idea I guess


I would recommend everyone check the condition of their wiring out. I bet this is more common than it seems.


HTH Somebody

 

Yeah, it's common all right. Nice pics. The lugs get resistance and the heat really fries the components. I have seen guys replace a switch with cooked connectors and wonder why it's back in a month. Check ALL the connectors related to the blower, especially the resistor pack in the blower housing. Any undue resistance will generate more heat in the connectors and wiring.

 

As is usually the case...I forgot to grab the camera to take some pics when I put everything back together.

Anyway, dropped by the boneyard and grabbed a new switch for the HVAC control head.

Ended up yanking this one from a '82 4cyl Camaro. Everything was fine on it, including the connector I needed. HOWEVER, the power connection that was NOT burnt on my car was COOKED on the donor car.

I yanked 2 more Firebird's apart, and one of those cars had burnt up wiring......pretty common. Nobody noticed it until the smell smoke, or the blower stops working.


I ended up using sleeved spade terminals on everything and spliced the new connector as well.

It only took me 30 minutes once I sat down in the car and put my toolbox right by the door. I was motivated by the cold... I was putting those little push on clips onto the vacuum connection, and kept dropping 'em. Realized I couldn't feel my fingers.

Got it all together, turned the key on and........NOTHING. Cussed for a minute, lit a cigarette and looked under the hood...I could hear the relay energizing when I played with the switch inside. Looked closely and realized I'd never reconnected the power to the blower motor after testing the motor with a direct power wire.

Plugged it in and the fan came on

Cranked the car and let it and I warm up. Put everything back together, put up my tools and it was nice and toasty inside the car.


Later