Fan In Heating Controls Not Working

[RAF]

Hey guys, Ive been having an issue with my 2001 Sierra for the last few days. When I try to turn the A/C or heating fan control on nothing blows out. I can hear the A/C compressor turn on and the light marked A/C goes on and the temp from cool to hot works aswell.

Everything seems to be working except the fan does not go on. I can even hear a click when I put it into high but still nothing blows out of the vents. I checked all the fuses and they are all ok. This also happened to me 2 weeks ago for one day and then went back to working like normal

 

Any help would be greatly appreciated

thanks

[tesnoboy]

Hey guys, Ive been having an issue with my 2001 Sierra for the last few days. When I try to turn the A/C or heating fan control on nothing blows out. I can hear the A/C compressor turn on and the light marked A/C goes on and the temp from cool to hot works aswell.

Everything seems to be working except the fan does not go on. I can even hear a click when I put it into high but still nothing blows out of the vents. I checked all the fuses and they are all ok. This also happened to me 2 weeks ago for one day and then went back to working like normal

 

Any help would be greatly appreciated

thanks

Have you tried it without AC on? How about with it just on vent, you turn the fan speed control through its speed ranges and does it change speeds? If it doesn't, it is probably the resistor module under the dash. They crap out especially when they get hot. You also said it didn't work on high either which is controlled by the fan motor itself. Be sure to double check everything slowly and separately before you waste a lot of money on the wrong thing. Good luck!

[RAF]

Yes, all speeds are not working but everything else is working. It does the same no matter if it's in the A/C or Hot position

[tanked_darren]

Check the blower under the passenger side dash.

[RAF]

I just went for a short drive with the fan on 2 and nothing came out. After about 10 mins I felt the fan blow but it was really week. I tried to put it onto 3 and 4 and it just stopped working again.

 

Any idea?

[tesnoboy]

I just went for a short drive with the fan on 2 and nothing came out. After about 10 mins I felt the fan blow but it was really week. I tried to put it onto 3 and 4 and it just stopped working again.

 

Any idea?

That sounds like the resistor module under the passenger side dash. Does it work on 5? The fan itself controls that speed.

[pistonslap]

Like tesnoboy said if it works on the high speed, it is most likely your blower motor resistor. I just changed mine a while back because the fan would only work on high. Here is a link to how to get access to the cabin filters. The blower motor is under the same plastic cover. (Post 8) http://www.dieselplace.com/forum/showthread.php?t=179020

[RAF]

No, when it doesnt work, it doesnt work on 5 either

Last night after I picked my gf up from work I had the fan on 3 and told her to kick under the passenger side dash. She did and nagically it started working! Later it stopped working I asked her to do it again and it worked again! lol

I'm guessing it's the motor blower resistor loose? I'll go take it apart in a min and have a look