Niceandeasy

My blend door is stuck on heat. Some times it will flip to a/c if lucky. How do I fix it. what wrong with it and how do I get to it.

ezone

Obtain a good service manual.
Do the climate control unit troubleshooting, perform the CCU (HVAC) self diagnostic function.
Determine fault codes present and troubleshoot according to the service manual info for that particular code.
Is there a code 3 present? (air mix control door, motor, or linkage problem)
Test each of the above according to the manual, and test its circuits to the HVAC control unit.


Air mix motor is on the drivers side of the heater case, you may lay on the drivers floor and look up to find it. Push/pull to "help" the servo (mix motor) and linkage move as you adjust the control dial from hot-cold-hot repeatedly.
Very few problems that I've seen here so I can't really just tell someone to replace a part and call it good.

Could be servo , could be sticky linkages, could be door inside the HVAC box, could be electrical, IDK.

CraigW

iTrader: (1)

Test Procedure:

(1) Ignition switch at 0

(2) Hold down recirc & rear defogger buttons while turning the key to II

(3) The recirc indicator lights for 2 seconds, then the self diagnostic test begins.


I still cannot grasp how there is not valve to adjust/vary the coolant flow through the heater core on the 8th gens..... wild, weird stuff.

Makes no sense.