99 Chevy S-10 Heater Repair
” recently bought a 99 Chevy S- 10 from a small dealer. During the test drive the heat blew out only cold air and only out the dash vents, not the floor or the defrosters but the AC compressor was kicking on. The dealer made me a great offer on this truck partly because I told them I would fix the heater myself figuring it was just a vacuum leak. 50 miles into the trip home it suddenly switched to blazing hot heat coming out and would not go back to cold. Now I have found a nasty vacuum leak and repaired it and the controls are working great now, defrost, floor and dash vents. However it is still stuck on heat, after taking the dash apart I found this seems to be electrical, I took it apart as far as I am comfortable and the door between hot and cold is staying on the hot side no matter where I have the control. There is a fuse in this circuit, I know because I dropped the plug and blew the fuse, so I know the fuse is good. What is my next step?? Do I replace the dash controls? Or the mechanism that moves the flap door? If it’s the latter, how do I get it out of the dash? Or is there something I missed? I’d rather do the work myself than deal with a dealership if at all possible. Any help would be appreciated Thanks in advance, Toby”
Your blend door is stuck. Sometimes you can try to get inside there and lubricate the door, as they are plastic and sometimes just stick. I realize there is little working room in there, BUT if you can, lots of guys will just break off whatever is holding the door in the heat position and then just put a coat hanger or even an old fashioned hand choke assembly on that blend door so they can open and close it manually. That way you don’t have to mess with all that electronic crap which breaks quite frequently on those Chevys. I see it all the time. many times you end up buying the entire heating assembly to fix it correctly, and that isn’t cheap, so bypassing those stupid controls is an option. Actually fixing those electronically controlled systems really can only be done by a professional mechanic, unless you want to just guess with some VERY expensive parts.
