My 1997 Montero LS heater control **** will go all the way to the full hot position but springs back to about 3/4 position. Temperature out of vents is weak. The factory manual talks about a heater control valve but does not show its location. I do not see it in the HVAC parts diagrams. Anyone know if this thing is in the engine compartment? I did replace the heater hoses when I did the water pump but can't recall if the hoses hooked to a valve. Thanks for any wisdom- Jim

 

follow the control cable

 

I pulled the radio/ HVAC control trim panel off (2 screws at top of panel, 2 pull to release clips at the bottom), removed the upper and lower brackets that hold the control in. I pulled the control out as far as I could and noticed that the temp control cable was kinked. The cable pushes for higher heat and it was kinked at the control lever. I stuck a long screwdriver in and straightened the cable and now it will push all the way in for max heat. I'll get a cable on order and replace it when I can. Anyone have experience replacing this cable? Wondering if there's anything else I should replace while I'm in there?

 

glad i could help

 

Just as a conclusion, the temp control cable terminates at a lever on top of the plenum behind the glove box. Remove the 2 glove box stops by pushing the end closest to you from the outside of the box and sliding it back. Wiggle and turn to get them out of the slot. The box will now drop down. The cable end is to the right close to the firewall. There is no retaining clip on the cable, it just slides up and off.