Blower fan not working

[wczimmerman]

So, the truck still has the issue but it would seem to be better. Does anyone know where I can source a replacement plug for the harness that plugs into that A/C Heater Control switch?

 

[chengny]

Below is a link to an NOS/NIB rotary select switch - for $29 with free shipping.

The part number (16001570) is correct for your truck.

I'm sure you can find these at any number of auto parts stores/web sites as well. But they will be more expensive and more importantly, they will be aftermarket replacements. That is a great price for an OEM switch. I'd jump on it if I were you.


http://www.ebay.com/itm/1983-88-CHE...ash=item3cf47b2c73:g:LjUAAOSwBLlU9hOQ&vxp=mtr

 

[wczimmerman]

I appreciate the link! I was able to source the switch locally but at some point I will need replace the plug that connected to it. That was what I was originally asking about.

 

[hatzie]

I appreciate the link! I was able to source the switch locally but at some point I will need replace the plug that connected to it. That was what I was originally asking about.

The part number for each plug in your harness is in the GM wiring diagrams. I'm not sure if it's still available.


My Droid from orbit

 

[wczimmerman]

For anyone else that may be looking for the part number of the wiring harness plug, you can get it (still!) through the dealer or through Amazon. The part number is 12085493. Here is the Amazon link.

It comes with enough wire and connectors to splice into the existing wiring. I am planning to get this done soon.

 

[Rick Shootist]

thread back from the dead... 1990 GMC Jimmy. No fan blowing, was only working on high previously. I already replaced the relay #15-8189 / #14036273 (on top of the heater/AC box on the cowl). A/C compressor works fine, just has no fan. Not a spec of rust on the vehicle so unlikely a ground issue. Won't blow for heat or vent either, no fan at all.

 

[Rick Shootist]

also, the purple wire coming from the relay going to the fan box gets 12v with the ignition ON regardless of fan switch position. If I jump a ground from the negative terminal of the battery to the fan box ground, nothing changes, no fan.

 

[Rick Shootist]

The vehicle in question is not the one in my avatar, that one has Vintage Air.

 

[Rick Shootist]

Blower fan repaired. Bottom line I replaced the assembly. Having said that here are some things to check if you have the same problem. There are a few components under the hood that do 90% of the work.

There is a red wire across the top of the firewall. It is referred to as a J-post connector. Check for ignition on 12v hot on both sides. Next, pull the purple wire on the bottom of the fan itself. Check for 12v w/ignition on here. If you have power here, the issue is at the blower motor or the switch on the dash or the wiring in-between the two.

If you have no power there you either have a bad relay (little removable box that the purple wire comes from) or a bad resistor (under the four wire T-connector on the heater / ac box).

Pull the blower motor. Put 12v to the lead that the purple wire attached to. Put a lead from the battery negative terminal to the blower motor metal frame (ensure you have bare/exposed metal at the ground hole on the frame. The motor will either work or it won't. If not, buy a new one. Get one with the squirrel cage fan attached. Your old squirrel cage fan is likely brittle and will almost certainly break when you try to remove it from the post it is pressed onto. The new ones are not pressed on, but use a D-shaft with a nut. Better design.

Before installing the new blower motor with fan, scrape the paint off where the ground strap is attached. The HVAC box is fiberglass and HDPE, and you must have a good ground to the firewall. You can spray paint back over it later.

Commonly, the blower motor will slowly start to seize. This causes greater and greater resistance over time. That causes the switch to only work on higher and higher levels until you get to max fan and eventually it dies. It may or may not take out the resistor first. The resistor is what allows the thing to spin at different speeds in the first place.

You can check the resistor for continuity with a meter, you can also pull the two sheet metal screws and simply look at the coiled wires for breaks. They are still available from GM through Rock-Auto, so is the relay and the blower fan motor with squirrel cage fan, though these are aftermarket. In my case I was able to buy all of the parts made in the USA or Mexico - nothing from Taiwan or China.

Hope this helps someone.