A good friend of mines heater isnt working. He said there are 5 wires going to the blend door. 3 of which go to the temp control and he suspects the other two are hot and ground. He has checked the blend door fuse and all is good. The wires coming from the temp control all change resistance as he changes temperature. Which wire should supply voltage? If the fuse is good is there a relay or something else that can keep the voltage from getting to the blend door? Thanks in advance for ANY help.

 

Check the manual for a relay. but Hot should be something like black or red wire. i thought the blend door was all vacuum, but i could be wrong.