1998 Blazer LT
4.3 4x4
Electronic Climate Control

Heat and air work fine along with speed and temp control. However direction control does not work. Air blows out of vents mainly, with a slight floor and defrost air flow. Control Module has plug in back going to hvac, then wire from hvac goes to vacuum manifold(behind ashtray). Could there be a vacuum leak somewhere or do the Climate Control Modules have a history of failing.
Any imput would be appreciated, since the dealer does not carry Control Module.

 

**Moved to 2nd gen Tech.**

 

I just had to repair mine.... its probably the vac line going to your vac canister or the canister itself. the canister is located in the drivers side fender well behind the ABS unit.. very hard to see...

 

mines a 2000 and im having the same issue these topics have been coverd before but I still cant figure mine out. I replaced the electronic heater control and the vacuum port and all the vacuum actuators as they had some transmission fluid in them. im wondering if all the actuator lines are clogged and theres a small crack in the main vacuum line from the engine to the control port.