ac heater control-digital

[97grmarq]

I'm looking into purchasing a 1997 Grand Marquis-everything in good condition,except that the "digital" control doesn't turn on the a/c.When I click the temp to the lower #'s it still blows hot . I pressed the defrost button & the compressor did kick on(and off occasionally) under the hood ,but yet the interior was still blowing hot (not even warm) air?
Is this just a problem w/the digital control and replacing the complete control will correct it ,or the heater actuator/door etc.can also be defective,or maybe something else?
The old owner mentioned "he'd go to someone in the beginning of each climate change & the guy would switch something (do something),and then the cold air only would work,vise versa in the heating season. Please help!

[1987cp]

Sounds like it's got automatic temperature control that hasn't worked for some time now. The former owner must have had someone manually switch over the "blend door" from hot to cold and vice versa.

Gadget73's the mang to talk to about Box-body ATC (automatic temperature control), so maybe he can point you in the right direction for your digital ATC. Nonfunctional blend doors, from what I can gather, are a common ailment on the previous-generation ATC system.

[97grmarq]

Does it pay to 1st try switching the digital control box,or you think it's definitely the blend door itself broken, or maybe the blend door actuator?
(I assume since he had ac in the summer,the door itself isn't broken,and it probably is the actuator, or maybe the digital control is no good-but the buttons all click & change settings on the display when pressed [ALL DIGITAL-NO KNOBS] ? )
Also,would you exactly know (pictures,etc.) what the guy maybe was doing before the summer and before the winter to change from all cooling to all heating? Was it manually closing & opening the blend door or was he switching wires on the control? Would anyone know exactly where it's located? How to get to it?

[2000marquis]

i had to replace a little module behind the motor right beside the a/c box in the engine conpartment

[97grmarq]

did it yourself,or had it done? Please clarify what part and exactly how to access it.
Thanks in advance.

[p71towny]

It is the actuator motor and it controls the blend door. They go bad quite often and requires removing the glove box door to change (if you can reach in there. I had to remove the dash to get at it. The dealer wanted like 700 to change it. I did it myself, droped the dash and threw in a new heater core for good measure.

[97grmarq]

Can it be done just by removing the glove box door alone,or it's impossible .Also, please-----more details ----on where exactly this actuator motor is and how to get to it .

[1987cp]

I would imagine your Haynes or Chilton's manual should show some of the more basic details pretty clearly ......

[97grmarq]

BLEND DOOR MOTOR WAS THE PROBLEM- HAD TO REPLACE IT-EVERYTHING WORKING OK NOW.

[1987cp]

Glad you got it fixed! Don't suppose you got any pics?

[97grmarq]

SORRY,DIDN'T THINK OF IT.