Ness' Outpost

A month or so ago when I set the blower in my Chevrolet Cavalier (named Penelope) to settings 1 or 2 the blower didn’t run, but settings 3 and 4 worked just fine. That told me the blower motor was fine after a quick inspection of the HVAC electrical diagram in my Haynes manual. It also told me that it must be the resistor block since there is only one power line from the battery which loops through the 4 signal wires and the resistor block.

Parts

The resistor block is a simple plug and play connection. There is no soldering! You can yank out the old one and put in the new one. I bought one from my local GM dealership for $35 CAD. Canadian Tire has them listed in their Ontario stores for the Cavalier, but none were in stock when I needed them. Priced at $31 for the exact same part as the GM dealer grab one from Canadian Tire or check your local parts store.

Safety

I removed the fuse for the HVAC system and tested that the blower motor was not getting power on the higher settings which I knew worked. This prevents getting a shock while working on the vehicle’s HVAC system. If you are not sure of the proper fuse to remove, you can remove the negative terminal from the battery.

The Haynes manual strongly suggests disabling the airbag sensors. I did not do this step as I was comfortable that I wouldn’t be doing any banging or applying strong forces beyond normal use of the car that would trigger the sensors. Be very careful since you can be seriously hurt if an airbag deploys unexpectedly. Disengaging the battery is not sufficient as the airbag system has it’s own power system so it can deploy if your battery is unable to provide power.

Removal

You’ll need a 7/32 socket and a wrench. If you have a “snake” connector – I don’t know the real name, but it’s a flexible tube that somehow lets you turn a screw driver on one end and the other end rotates too no matter how bent or twisted the hose is. The snake driver was a huge help in this job since you’ll be working right up against the firewall on the passenger side.

Taking out the blower motor and fan assembly is rather straight forward and unfortunately you’ll have to do just that to get at the resistor block. Locate the blower motor behind the glove box and remove the 3 screws with 7/32 bolt heads. Drop the motor and fan assembly down slightly and rotate it 90 degrees counter clock wise to expose the connector. Remove the connector by pulling down on the locking pin and firmly disengaging the connector by pulling down on the plastic sides and not the wires. You may find that connectors stick a bit, likely due to a little bit of corrosion.

Now you are able to see the resistor block. It’s the green circuit board behind the blower cavity that is attached by two screws with 7/32 bolt heads. Remove the hidden back screw behind the block first resisting the urge to remove the front screw. The snake connector was very helpful here as the back screw is very difficult to access since it is pressed up against the firewall.

Remove the front screw and pull the resistor block straight down.

Installation

Insert the new resistor block into the slot in the lip of the blower cavity. Secure the front screw first tightly. Then attempt to secure the back screw. I was unable to engage the back screw and decided the front one would be good enough. I doubt the resistor will rattle free by the blower motor and I’m happy with only one screw holding it in for now.

The installation of the blower motor is the reverse of removal.

This entry was posted on Tuesday, August 28th, 2007 at 7:33 pm and is filed under Mechanic. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.