on a 93 Blazer Tahoe LT? The heat/ac has been working intermittently, I replaced the resistor and that didn't solve the problem. I removed the control panel most of the way (except the black and grey wire at the top and the cable) and I do not see where the switch is?

http://shop.advanceautoparts.com/web..._1162938875___

That is the part I got from advance, what is throwing is that appears to be for a dial and I have switches/levers/slides whatever you want to call them.

 

What ever lever you move to make the fan speed faster or slower, that is where the "switch" is.. the lever is part of the switch

http://www.Rockauto.com

AIRTEX / WELLS Part # 1S1834
{#16032480, SW196}
w/A.C. & Heavy Duty Heater

 

Thanks, I actually got one of those last night before I saw your reply just now. It's still not working and now is making a hissing sound when in the off position.

 

Hissing sound ? the controls need vacuum from the engine to operate the doors the change the air flow from floor to vent to def ( windshield)

when you have the cotrols set vent, floor etc, and put the fan on HIGH, do you feel air anywhere ? do you have the FAN at all ?

If not you need to make sure you have 12v when on high at the fan motor

If you hear the fan but dont feel anything, you have a vac leak ( the hoses behind the controls ) 1 comes from the engine, goes to the controls then to the damper motors ( looks like a flying saucer with a hose going in or out ) which pulls and pushes on a lever to open the doors for heat/cool vent/def/floor.

make sense? did I confuse you? ( i easily confuse)

all that stuff is accessable via the glove box and passenger floor area.

 

Thanks. I don't feel air anywhere. I think I hear the fan, but I'm not 100% sure. Since it wasn't hissing before I may have a vac leak. I had disconnected the hoses from the back of the control panel and when I pulled on them to get some more play I might have pulled it loose. I disconnected them as well as the wires from the control panel thinking the part I was given originally was back there, I though it was the wrong part, but went along since it is what came up for my truck.

 

with the truck off, turn the key ON, then move the VENT/Def/Floor control from the OFF Position (actually turns off the fan) to anything, vent, defrost floor.. etc..

then change the FAN speed from low to high, you should hear a change, you should definately hear it with the truck off, if not then you may need to check the FUSE panel and for 12v to the blower.

 

Thanks I'll try that. I didn't mention it, but I had already changed the fuse and the 12V to the blower feels secure.

 

a secure connection is a good thing here, but you need to check for Voltage to the connection and the ground of the motor.

You'd need a 12v test light or Multi-meter

 

the hissing noise your hearing is behind the heater swiches. there are vacuum hoses behind it you might have knocked them off when removing the panel. and for the fan not working, there is a relay to the right of the blower motor on passenger side firewall that looks like a little silver box with wires going up into it. that might not be working right. thats what turns the blower motor on and off.