heater problem
 

why doesnt my heater work. the guy who sold it to me said it worked fine but well it doesnt. i live in wa so a heater is something you really need. anywho it blows strong but it doesnt heat. so my question is what could the problem be? i hear that the heater in the s4 are crap if so should i just buy a new one? or just try to repair the stock one. also the light indecator on the heat side of control panel lights up when it wants to?? if you all know what i mean if not i could take pics

I had the same problem on my 87 base model.

The heater (heater core) is basically a radiator inside your dash board. The thing that determines whether or not you get heat is a valve that controls the flow of engine coolant into the heater core. This valve is actuated by Air Mix Control Motor inside the dash that's controled by the Logicon (the thing in your dash with the sliders and switches.)

To recap:

Engine Coolant -> Actuator / Logicon -> Heater core

Check the FAQ for links to the FSM (Factory Service Manual.) There's diagrams from 15-93 to 15-97. (15 being "Body Electrical 1", 93 being the page -1.)

Unless there's some wierd re-piping of the cooling system (the line that runs along the passenger side of the engine to a port in the firewall), it's probably your Air Mix Control Motor or logicon. (Though it could also be a clogged heater core.) I'm pretty sure it was the AMCM in my case, so I replaced the linkage the connects to the AMCM to the coolant valve with a coat hanger. High-tech, no? You push up, valve off. You pull down, valve on.

Basically take out all of the trim pieces and heater ducting under the steering wheel and have a peek in from the outside of the car, driver's side. You'll see something like the attached image. There's a L shaped piece, the top connector goes to the heater coolant valve, the lower goes to the AMCM. Feel up the plastic clips. Push on the open side to release it from the rod leading to the AMCM, then pull the rod out of the hole. Take your coat hanger, put a 90' bend in to top and insert it into the hole, swing the clip around to grab on to it.

It was a while ago since I did it, but I remember something about the coolant valve being stuck too. I got a pair of vice grips on the L bracket and giggled it loose. I also remember, for some reason, sitting in the driver's seat upside down (head under dash and feet up) but I think that was to get at one of the wierd plugs inside the dash.

I don't know if you can replace your ducting and trim pieces, I never bothered. I think there might be an additional issue of the front driver's speaker, but my car didn't have one to begin with so I can't comment there either.

Enjoy!

thanks i will try the hitec coat hanger if i can find a wire hanger

how do i get the rod(the side replaced with coat hanger) off of the bracket?" i'm working on this right now and i'm trying to figure out how to do this w/o removing the entire dash. i really hope i dont have to pull the dash apart...

nvm... i got to it and i have heat now. WOOT!