heater button stuck on 93 lesabre

[strikerty]

when i first bought the car it would sometimes flick to heater while driving and you would have to change it back to whatever you were using before , lately we havent been able to change it at all , it is stuck on heater. Everything works fan works temp control works and stuff but cant change selection to AC or Vent or anything only heater. Someone said something in these forums awhile ago about this problem and it ended up being bad grounds in some control box under one of the front seats . I cant seem to find this but its been months since i read it and there was never a problem before now because well . . . it wasnt summer lol and we didnt care . Now she wants her AC back . . any ideas on this? i was hoping to find that old post but after searching the forum i cant find it .. . hoping someone would either remember it or know what the problem might be
thanks guys

[DerekRH]

When this happened to my car (89 LeSabre) it turned out to be a vacuum line unhooked right across from the middle spark plug on the firewall.

[strikerty]

i thought by the 93 model yr it was electronic computer controlled heat interface . . . altho i could be wrong

[DerekRH]

That might very well be true. Don't know a lot about these cars just sharing my experience which seemed much similiar to your own.

[strikerty]

so . . anyone lol

[spinne1]

Originally Posted by strikerty

so . . anyone lol

It is probably your HVAC control itself. Get one from the junk yard (do you have a Pull A Part in your area?--cheap there) or ebay.

However, it could be a wiring issue. Subscribe to Alldata.com for your car and study the wiring diagram for the HVAC controller. See why it could be doing that. Does the button on your HVAC controller light up at the Heater position? Before when it would jump from whatever to Heater did you see the light change places? When you say Heater do you mean that only warm air comes out, and only on the floor? If you push the AC button but air only comes out the floor, BUT the air is cold, then perhaps you have a vacuum problem. If it is always hot air and always on the floor, you likely have a wiring or HVAC controller problem. If it is cold air and on the windshield, then you for sure have a vacuum hose that has come loose (in particular one of the two that connect to the funky shaped black box on the firewall next to the brake booster.)