Heater Controls

[TJ 450]

Hi, this is my first post 

The heater control levers on my 450 are jammed in the "on" position, thus the heater is on all the time. As far as I can tell, it is the flaps that the levers control that are jammed as they sound like they are dislodged. How much of a mission would it be to disassemble the black plastic unit that they are in? I hope it can be done without removing everything else first  BTW it's the basic version, not the ECC.

Also, does the entire  inlet manifold have to come off to clean/remove the throttle body?

Thanks, Tim

[koan]

Hello and welcome TJ450.

Jammed heater flaps are a common problem on 116 heater boxes. There's been quite a few posts on this in the last several months, a search for "heater flaps" should find an explanation on why it happens and how to fix it.

I might be wrong but I recall someone (styria?) saying only the bottom part of the heater box needs to come out to fix the flaps - which is simpler job than the whole box, but I suspect still not a lot of fun.

There are a couple of threads on heater box removal, one in the last week.

Don't know about the throttle body question.

koan

[TJ 450]

Thanks for the info, ...sounds like a bit of a mission. It should be interesting, though.

[Bandolero]

On my car, if I move the RH heater control past half way it will jam.
It is no good forcing it back as that won't work.

You can try gently "jiggling" it when you get to the jammed section.
This works with mine.
Gently move the lever down till it jams, then GENTLY jiggle it back and forth and it may release.
If it does, don't move the lever up any more than about 1/4 up. The heater will still get warm but the lever won't jam.
Works well for me as I DON"T want to have to fix it!!!!! 

[koan]

On my car, if I move the RH heater control past half way it will jam.
It is no good forcing it back as that won't work.

Just like mine, until I installed a travel limiting device - a block of wood glued to the heater box.

I'll do the foam job one day but I'm putting it off.

koan

[robertd]

Hi TJ450,
Welcome to the forum, before you embark on this mission with the heater box, first check the heater hose valve that is situated on the centre top section of the firwall in the engine bay. This simple valve is kept in the closed position by a vacuum, this vacum pipe can become brittle over time and crack, if the vacuum is lost the valve will open and allow the hot water to enter the heater box and bingo instant heat.
Regards Robert
PS I was quoted $1000 plus to repair the stuck heater in my 380SL. I couldn't come at that so I did my homework and found that the red plastic tube that supplied vacuum to the valve had a small hole about 3mm dia. I simply cut away the damaged piece and made a join with a rubber grommet. Fixed and I kept the $998 saving.

[WGB]

My right hand lever was stiff and if not pushed fully home it would not turn off the heater valve.

I loosened the screw ( I think it was a small nut from memory) under the dash on which the lever pivoted and this allowed it to go fully home and shut off the heater valve.

I think the real problem will be the flap in the heater box which will have lost it's foam.

I promised Nathan to do a PDF of the "Foam Fix" and will do this in the next few days if anyone is interested PM me with an e-mail.

Bill

[nathan]

Hi TJ, nice to see another wa member....
if you want another heater assembly, give me a post or email...im wrecking two 450s for body parts for my 6.9 so have two of these assemblies on the cheap!
regards
nathan

[oscar]

Today I noticed part of the connector rods attached to the heater controls whilst digging around behind the glovebox.  Do you think these could be jimmied to help get the heater flaps free?

[koan]

Today I noticed part of the connector rods attached to the heater controls whilst digging around behind the glovebox.  Do you think these could be jimmied to help get the heater flaps free?

I was able to free my right hand side lever, at first just a bit of jiggling of the lever was sufficient, but it eventually got to the stage where I had to disconnect the flap from the lever and jiggle the flap directly. Sometimes it's stubborn but with a loose light grip and gentle jiggles I could always do it.

When it's free i suggest you readjust the lever / flap relationship and don't move the lever up beyond half way.

koan

[WGB]

I have made a PDF copy of the Heater Flap Fix as found in M-B Technical Companion and have sent a copy to Nathan as promised.

They say it is a 10 hour job and it will be one of the first jobs I do on my car when the paint is finished.

I also have a stripped heater box sitting in my shed but as it's raining cats and dogs here in Perth tonight I'm not going down to Photograph it.

Bill

[John Hubertz]

Out of curiosity I'm wondering if a properly positioned small hole would allow someone to budge the flap and free the mechanism using a thin rod.  Some Lincolns have this same problem and are almost as difficult to dissasemble, but can be freed up when they jam using this little "helper" method.