blower switch problem?

[derekBer]

i have a 92 blazer with a/c. today after about 10 min of driving (heat on) i could smell something burring. a mintue later i noticed smoke comming from the fan speed control. i stoped and parked it for the day. i pulled out the fuse for the heat/ac i ran the truck for 20 min or so and couldn't smell anything burring. i tried to take out the controls got them free but couldn't get them out far enough to work on?

[derekBer]

i replaced the blower switch, $10 from GM. Everything seemed to be working fine...... i drove the truck for about a day when the heat selctor switch started to burn up. This is the electrical switch that allows you to select heat, a/c, vent ect. I priced the switch at the dealer and it was 30 dollars...... for 25 dollars I got the entire assyembly from the junk yard. Works good, the fan just doesn't work on med or low. i think this has to do with a relay....... that is my next project!

[Teal95Jimmy]

Sounds like the blower resistors burnt up on you, try checking those out

[skyzend]

I just replaced the blowerand resister pack in my 1999 Blazer.

I can't commentv on the switches burning up as miner were fine but ....

Just prior to replacing my blower I was losing speeds. Before the fan finally gave out I only had high speed none of the other speeds settings worked.
Now with a good fan I started checking and pulled the blower resister coil assembly from the firewall.

You have to cut into the rubber housing assembly to get access to the mounting screws. Just cut along the recessed "cut" outlines and you will be fine. It will likely be necessary to remove the flat copper ground connection from the firewall as this is any easy thing to do and makes access a whole lot easier.

I checked the resistor paths with a meter and found that the paths were all broken circuits ... ie the resistors were toast. The high speed has no resistor path so that one always worked. The replacement cost a little over $20. When checking the resistor values, most are very low ... less than 1-2 ohms. actually there is a wiring diagram on this site somewhere in the help threads that give the exact values.

Hope this helps, Once the rubber housing is cut, the resistor coil assembly can be replaced in about 5-10 mins. Reseal the rubber housing back over the access bolts when done using black window sealer/adhesive or similar product when you finished.