View Full Version : fan blower speed selector

04-09-2008, 10:18 PM
heater/ A/C blower only works on high speed #4, nothing on 1 , 2 or 3. I took the speed selector apart and cleaned it, re-lubed it put everything back together but no change. Before I rip out the blower motor, anyone ever dealt with this problem? Thanks

a few of the Astro /Safari mini vans at work (service vehicles) have the same problem.

04-10-2008, 12:08 AM
Have that problem sometimes on my old truck, connections to the resistor that slows the fan, could be different in your case, but most likely the resistor itself, not the fan.

04-10-2008, 07:53 PM
I second Grant's motion!! 99% chance it's the blower resistor block very, very common on GM's. I have changed many!!

04-12-2008, 06:16 PM
Hi guys,

Just going all out today to get my name on evey thread. Yah, the $@&*$ blower motor is going in my truck but hopefully I will get by on the electric windows for the next six months.

04-12-2008, 11:46 PM
I third the blower motor resitor block. Have changed two on different GM vehicles. Had the same problem though. Resistor block fixed both.

05-26-2008, 09:11 PM
ive read that the blower motor going dead was a result of the blower motor resistor block, where is this exactly and does anyone have a pic of one, i need to know what im looking for when i fix it.......if you have the pic plz send it to kitchenskevind@yahoo.com

05-26-2008, 11:04 PM
First pull the switch out and clean the contacts, they are the usual problem.

05-27-2008, 01:29 AM
thank you grancito, very much!

06-08-2008, 10:13 AM
Thanks Guys, finally got around to relacing the blower resistor block yesterday, (17$ canadian at a Chev. dealer) and now have a working fan/AC just in time for the high humidity were having here right now.

Husker 6.5
10-27-2008, 08:05 PM
This entry is being left to overwrite the ID left by liyanricaoqiyue1314 so the thread can be accessed.

Husker 6.5

06-18-2009, 10:00 AM
Hi Guys,

Havnt checked in in a while but this one caught my eye. I've replced like 3 a/c/heater control modules in the dash over the last few years. Doing so has restored full functionality of a/c and heater blower systems. It's also drained my bank account 125.00 each time.

Based on the original post here though by 99C2500, I'm starting to think that this blower motor resistor block is at fault. Right now, I only have speed#4 on my fan with either a/c or heat on. Even w/o the a/c on and the temp knob selected to cold (blue), the blower only works on speed#4.

What is this blower motor resistor block, where is it and wher ecan I buy one?

Thanks, Mark

06-18-2009, 12:55 PM
Did you look at the wiring harness when you replaced the switch? You may have loose connection causing your problems.

06-18-2009, 01:19 PM
I had thought the same thing only I dont know how I could manage to get 6-8 months of full service out of each module before things start getting a little funky again.

All speeds work for both A/C and Heat for about 6-8 month. I had one work for almost a year and then returned it under warrenty (2 yr.) to one of the famous e-bay resources.

If it's a wiring issue, I'd sure not know where to start on that and I'd like to know how it could work just fine then pretty much not at all. But I also know, thats wiring for you on occassion.

Anybody have a pic of the thing w/ a resource to buy a new one?

Garth J
06-18-2009, 02:04 PM
My buddy had the same problem with a headlight switch and finally bought one from the GM dealer and has no problem since ...G

06-18-2009, 02:33 PM
If the connection is loose it will make a lot of heat and burn up the switch. I hade that problem on a 97 Suburban a few rears ago.

06-18-2009, 02:37 PM
I didnít know any one else sold those switches after market G. The ony place I could find them was at the GM dealer. Was it LMC or something?

06-18-2009, 02:45 PM
OK, getting back to the Blower Motor Resistor Block.....does anyone have a picture where this is on a 1999 K2500 SLT? I looked under the passenger side dash at the blower housing and dont see where this thing lives.

Do I need to take covers off or lower the blower somehow to get at it?


06-18-2009, 10:32 PM
I made a search and someone who changed one didn't say where it was, but on my 82, it is under the hood on the air con. part protruding from the fire wall. Look there.

06-19-2009, 08:03 AM
Its by the blower motor remove the trim cover passanger compartment and you should see it

06-19-2009, 03:46 PM
Thanks John

06-21-2009, 01:32 PM
GM sure didnt make things easy for themselves over the years. Seems to me the europeans and asians figured out common design features/components over a wide range or platforms a long time ago. Maybe thats why they're eating our lunch.

In the case of my particular truck, the Blower Motor Resistor Block (4 wire) was inside the passenger compartment, behind the glove box and on top of the actual blower system housing unit. I'll add with about no access for human hands to get at and fitted with a plug that appears must have been installed before the whole assembly was bolted up into place.....thats what I was afraid of. None the less, let this be a message to folks that may be contemplating this repair....leave about a half day of work and dont be surprised if you actually have to recharge your A/C system afterwards because of so much wresteling with the thing....so much for "attaches with two set screws".

07-07-2009, 04:19 PM
Just goes to show, every once in a while I still get caught out. After replacing what clearly seemed some faulty electricals; resistor block, blower fan switch assembly, it turns out that there was a poor connection at the plug to the blower motor selector switch. Seems the plastic clip on the switch assembly itself has the connector needing to be pushed on too far to click in place. I couldnt beleive this was the issue but after several tries and now a few days of operation over the road, everything is working just fine. Needless to say this was very difficult to diagnose but I thought I would include this in the string here as something for others to check as well