After searching through other threads I am unable to find an answer to my question so hopefully someone can help. I own a 1993 4 door 4x4 s10 blazer. The ac blower fan went out last summer so I replaced it along with the relay. Last week while driving it stopped blowing. The heater and AC still work and I am sure it is a problem with the switch. Unfortunately, after removing the two screws under the switch housing there is still not enough slack in the cables to pull it far enough out to do anything with it. I have removed as much of the dash around it as I can but have had no luck. How do I access the backside of the fan control? Any help is appreciated.

 

There's usually enough wire to stretch just enough to pop off the conector on the fan switch. I just took a flat blade screwdriver and popped up the release on the connector. You're never going to have the room that it seems you want without some major disassembly but it isn't really necessary. Just pull on the assembly and wiggle it a little as you do. I think you'll be OK. Just don't go overboard. To put the connector back a pair of duckbill pliers was my weapon of choice. I've had mine out so many times because of this and that that I should have put a zipper on it. Thank goodness it's all fixed now. I can't imagine sticking my hand up behind the panel to get at the switch.
Quick question. Does your blower run in low? If it doesn't it might not be just the switch. The low speed doesn't run through the switch even though it is marked that way. Check your resistor (1 connector and 2 screws) in the engine compartment.You can tell if it's fried by looking at the backside where the acrual resistors are.

 

After you get the fan control out as far as you can look at the back side, there are 4 small screws that run in from the rear. I believe they are 7mm or 1/4" heads,use a small box end wrench to remove them, that will alow you to disassemble the unit and may give the room you need.

 

Thanks for the pointers. After checking the switch, resistor, relay and blower motor with a multimeter and finding nothing wrong (except for a very dirty resistor). I reassembled everything without installing the blower motor so I could watch it. It works fine. When I install it and turn it on very small amounts of air blow out. After studying the system I think I have traced the problem to the vacuum system. I have known my 4 wheel drive isn't working so I decided to find out why. I jacked all four wheels off the ground put it in 4 wheel drive...nothing. Then i squeezed the vacuum actuator under the battery and bingo the front wheels engaged. Since the vacuum system controls both the heating/ AC system and the four wheel drive I think this is where my problem lies. Any idea where I might look? Thanks in advance.

 

If you have access to a hand held vacuum pump like a Mity-Vac, you can pretty much troubleshoot the entire Htr/AC system including the vacuum actuators. You have 3. One is in the center and the vacuum connection is just to the right of the gas pedal, one is in the passenger kick panel and one os in the cowl on the right side and you have to remove the cowl to change it. If you can pull the HTR/AC control again, you'll see the vacuum portion of the control. It's a rotary vacuum porting switch (for wanr of a better word) and you can hook up you vacuum pump and operate the system from there. You may have a collapsed hose or (I suspect) a leaky actuator, probably the one in the center that controls where the air is distributed. Common problem on these rides. Never owned one (and that's 3 now) that I didn't have to replace at least one. Good job troubleshooting if a little unorthodox. You also might check the vacuum tank and the check valves that are in line with it.