No Heat

[aae42]

OK. So I finally got some time to re-visit my (lack of) heat issue. Since I hadn't done any service to the radiator since I bought it, I figured that even though a plugged heater core was not the problem, the coolant needed changing anyhow. So I back-flushed the heater core, and flushed the heck out of the entire cooling system. It is now full of fresh glycol / water. However, it barely has any heat (with the control valve manually opened).

So, it looks like Phil and Beno are (once again) correct. With the control cable off, moving the temp control does not more the cable. So I'm pulling out the service manual as Phil suggested. Any hints / tricks / known issues? I haven't looked yet, but I assume all the things I need to check are buried in the dash? Not looking forward to this...

looks like we got the exact same issue, my bet is that cable also opens a mixer door or something... i've been meaning to take a look myself but haven't had the time... i got a free morning though...

EDIT: well, yea, i guess that's what was mentioned

EDIT2: well i'm having a hard time finding this in the FSM, i see AC-49 which is the water valve control cable, but i don't see anything for servo motor air mix... maybe i don't have the right one...

 

[Cruzerman]

As always, I'm putting out the disclaimer that I could be wrong. I haven't really done any research yet. But I believe that the cable does not open the door. There is a servo motor that ultimately moves both the flapper and cable.

 

[aae42]

As always, I'm putting out the disclaimer that I could be wrong. I haven't really done any research yet. But I believe that the cable does not open the door. There is a servo motor that ultimately moves both the flapper and cable.

and you can see it from the driver's footwell, mine will turn with the heat control but i don't know where it goes to from there...

 

[aae42]

well... now it's not turning.... that's interesting


i did hook the cable back up to the mixer though... maybe i'll unhook it again and see if it starts spinning again

 

[Cruzerman]

Is there any way to manually open the flapper / door? I have the cable off the heater control valve, so I can manually adjust that. But without the flapper open, I get no heat.

 

[22xxxWC]

im reading this, hoping for an answer to what issue im currently having w my 97. heater control valve was done as PM a couple of weeks ago when i first got it. had heat last week, as of 2 days ago, i seem to have gone from not too hot, to no heat as of yesterday. It did however on my drive home last night blow hot for about a minute, than back to cool. have a mechanic friend coming over tomorrow(im off) and help me put in a new dishwasher and microwave. We are gonna try and get the heater figured out. so any tips would be appreciated, ill keep posted if we get a solution. checked coolant level just now, filled to the top.

 

[bigCatdiesel]

Is there any way to manually open the flapper / door? I have the cable off the heater control valve, so I can manually adjust that. But without the flapper open, I get no heat.

Any luck on this? I'm fighting this too right now. The FSM is vague so I'm piecing it together between my own troubleshooting, FSM and Mud search. I think my problem is the air mix servo motor. Check out this thread...
Water Mix Valve Servo/Cable

I found an air door lever on the passenger side footwell. It doesn't move at all regardless of which buttons I hit. I can manually switch it and I get some heat to the feet vents. Still not clear which flaps it controls.

Next step for me is probably pulling the dash looking for that air mix servo motor and cable. My water mix valve cable is also stuck.

John

 

[aae42]

to make matters worse i'm realizing this is all totally different for those of us with climate control...

but no, still no go... i've triple checked all of my fuses, but i can't get my water mix motor to engage now... and if i just unhook the cable and turn the valve on the firewall myself, i still don't get heat out of the dash, rear only.... (on my LX it's right in the driver's footwell far right)

took the center dash bezel out and checked all of the connections going to the back of the climate control too, everything looks fine... i wonder if it's something wrong with the temp sensor, anybody know where the temp sensor is on the climate control system?

@22xxxWC you've got a 40th, anything ever come of your attempts??

 

[22xxxWC]

to make matters worse i'm realizing this is all totally different for those of us with climate control...

@22xxxWC you've got a 40th, anything ever come of your attempts??

a good friend has my LC ar his shop, been there since last week. doing a heater core flush(also found PO had the rear heater was bypassed POORLY under the car, and that was causing alot of restriction). Theres an aftermarket headunit in there as well as the remnants of a previous headunit(sat radio antenna wires/6 cd changer wires) that were jammed behind the climate control unit, partially blocking the doors from closing. after freeing the wires had some heat, but im wating to hear back from him later today on how the heater core flush goes. Im fine w leaving the rear heat dissabled. just need some cabin heat.

 

[schradec]

to make matters worse i'm realizing this is all totally different for those of us with climate control...

but no, still no go... i've triple checked all of my fuses, but i can't get my water mix motor to engage now... and if i just unhook the cable and turn the valve on the firewall myself, i still don't get heat out of the dash, rear only.... (on my LX it's right in the driver's footwell far right)

took the center dash bezel out and checked all of the connections going to the back of the climate control too, everything looks fine... i wonder if it's something wrong with the temp sensor, anybody know where the temp sensor is on the climate control system?

@22xxxWC you've got a 40th, anything ever come of your attempts??

not sure if this is the right part but may help.

 

[Cgall100]

I thought my servo motor went out and ordered a replacement and an AC amplifier used/refurb from @CruiserYard. I changed the amplifier first which is accessible behind the head unit. Cable is now moving smoothly but didnt solve my heat problem yet so the search continues.

 

[Lams]

Great topic, especially with the Cold front.
Any update?

 

[Cgall100]

i'm planning to replace the water pump and pressure flush the cooling system. Little concerned that my head gasket needs replaced as I'm burning through coolant with no visible leaks.