1973 280SEL (116 025) heater controls / water entry

[Frankenstien]

Hey all ... I was surprised and pleased to find a discussion group focusing on 116's ... my car is kind of an oddball as I believe it was produced for the German domestic market and exported to Canada as a used vehicle ... the Service Manual Library matrix here doesn't list any '73 280SEL's ... I had high hopes of finding literature specific to my car ... any thoughts in that regard?

At the moment, I seem to have a jammed defrost duct door mechanism that has me a little baffled. The 10mm nuts on either end of the heater (vertically-oriented slider-type) controls pivot were loose - in retrospect, perhaps done intentionally to protect the mechanism from being forced and broken. It may be that some foreign object(s) found its' (their) way into the defrost duct outlets from above.

As I have no owner's manual or service manual literature to guide me, I have no concete ideas about what the control symbols mean or a procedure for setup / adjustment of the heater controls.  Here's a photo of my heater controls:



It seems like there is a control rod to each defrost duct door on either side with a heater duct door (?) control rod forming part of the linkage on the R side. With said linkage still intact, when manipulating the heater duct door (?) control rod on the R side, the little bit of movement possible seems to be stopped by the R defrost duct door control rod and whatever is jamming the door.

The defrost duct doors were likely never meant to be independently operable, so, I have wondered to myself if, instead of foreign object entry as the issue, perhaps one or both doors have rotated past its'/their normal operating range and is/are consequently bound up / over-center somehow... or ... is there some control sequencing / procedure to setup / adjust these controls that has so far eluded me?

The issue that precipitated pulling the lower dash panels off is water entry in the R side (passenger) footwell - so far as I can tell, water is dripping down from the center seam of the large round duct encasing the heater blower motor - meaning I likely have years worth of debris plugging up the drain holes in the exterior vent cavities below the windshield and, consequently, rain-water spill-over into my pass. footwell.

Any recommendations as to the best way to unplug the exterior vent drain holes would also be most appreciated.

Thanks, FFF

[koan]

A very common problem.

The foam on the heater flaps within the heater box disintegrates, in a couple of places the foam functions as a hinge and the flaps end up jamming.

Repeated jiggling (no force) of a stuck lever might get the flap back in the right place (it did for me) but you then need to be careful using that lever.

It is possible that something has fallen in and is jamming the works but unlikely.

The heater needs to be remove and "re-foamed". I see you have only a heater, but I assume the "technology" is much the same as the HVAC box most of us have. Removing the HVAC box is a major task, maybe your heater only box will come out with less trouble.

Search this forum for related terms, HVAC, foam, flap, etc.,

Have a look at this thread "Airbox" which has  lots of pictures of the refoam procedure.

The two outside levers with red symbols control left and right side heat (yes, independent left and right heat control), up is hotter. The other two levers with the arrows control air distribution. The up arrow is demist/defroster, up is more. The down arrow is footwell, this time down is more. The odd legend above the fan speed knob is a graphic representation of where to set the levers for DEFrost, full left and right heat, defrost vent open, footwell vent closed.

Usual way of unblocking the drains is from underneath by poking a thin bit of wire up the drains. HVAC cars have two or four drains.

Your heater box is covered in the library under "Climate Control Manual", in section 1 "Heating Ventilation Air Conditioning 1" the low number jobs 83-020 and 83-1xx are relevant.

koan

[joshm]

Hi Frankenstein, I am a '78 280SEL owner and have the same heater setup as you (no A/C) judging from your photo. Today I was trying to revive my fan motor etc, and as part of the work I went to swap the main blower controller with another I had floating about. Alas, all the wires fell out of the back of the controller before I could make note of their layout, and I have blown umpteen fuses trying to guess how they went in.

I was hoping that you might be able to help me out and tell me the wiring since it sounds like you might be taking the controller out too? There is a plug and socket affair on the back with 8 numbered pins (in addition to the cable retainer and spade connector). There are six wires, of the following colours (from very recent memory!):

Green w/white stripe
Green w/yellow stripe
Green w/red stripe
Green

Brown
Black w/green stripe

If you would be able to tell the pin number for each coloured wire I'd be very grateful! 

Thanks,  JoshM

[Frankenstien]

Hey koan ... thanks for helping me out ... so far I've read through p's 1 & 2 of the 'Airbox' thread (wow!) and have d/l'd the Climate Control Manual (Heating/Ventilation for '73 450SE, 450SEL - they use same document #'s and appear, essentially, to be just like my '73 280SEL's) sections you referenced in your reply.

I've got a much better idea what's going on with those levers now ... thank you so much for that explanation and those references ...

I may be able to glean the setup / adjustment of the four principle levers from the 83-1xx series of documents - even though I have no intention of pulling the airbox or blower.  koan, I'll try your 'jiggling' advice directly on the cable control going to the defrost duct flap - provided I've identified it correctly.

Some things I've got to get straight (in my mind) are:

- there is one defrost ducts flap (aka "air outlet at windshield") controlled by one cable control attached to lever '17' (2nd from left/UP arrow symbol in my photo, illustrated on p's 3 & 4 in document '83-020.pdf' - "Operating lever for air outlet at windshield") on the L side, right?
 What else is going on at the L end of the slider controls pivot shaft?
 Does the 10mm nut being loose at the L end mean lever '17' will not actuate?
 Under what conditions (lever/flap positions) should it be tightened?
 Should I expect to be able to get my hand in there on the L side to physically manipulate the cable control / defrost duct flap?

- because the 10mm nuts on both ends of the slider controls pivot shaft were loose, and, I had initially mistakenly assumed I could sort things out from the R side, I've kinda' lost track of the various door position directions - document '83-100-2.pdf', page 6, step 66 & 67 show what to do with the R side ... only reference to L side found so far is step 12 on page 2 of '83-100.pdf' ... can anyone elaborate on overall lever setup / adjustment / door position directions?
... step 70 on page 7 of '83-100-2.pdf' talks about re-installation and adjustment of the operating lever for summer air (located directly above heater controls) - presumably this is un-related to what I'm trying to sort out.

Oh, and where exactly should I be looking to find the (presumably 2) drain holes associated with the 'ornamental grille on air inlet' (bottom of cowl area in front of windshield) ... I have seen reference to a 'water box' (steps 10 & 13 on page 2 of '83-120.pdf') in conjunction with the blower re & re ... is that my culprit?  It's been a while since I scrutinized this area of my car from below - what location (L & R, R only?) and shape of box should I be looking for the holes in from underneath?

Thanks guys ... FFF

[Frankenstien]

joshm ... I was unaware of your post until I just tried to post a reply to koan and the group ...

'main blower controller' ... I'm not planning on taking mine out ... are you talking about the back of the combination cable / electrical knob in the center of my photo?  I'd photograph it for you if I could get at it but first I have to understand what location and specific group of wires you're talking about ...

I'll go outside to my car in a little while to look and see if the wire colours you mention go to the back of the knob I think you're talking about - right now I have pretty good access under the dash as I obviously have the radio out of the console and also have the L & R lower dash panels off.

I'll get back with you here if I find what you're looking for (or even if not).

FFF

1323PDT24APR10 edit - joshm ... sorry dude ... I tried to photograph the wires / connector of the main blower controller knob (assuming we're talking about the same thing) while still in place ... my camera's pretty small and I did manage to sneak it in and under, however, the (super-macro w LED settings) photos don't show what you need to see.
I think koan has provided you with some info in a reply directed at you in this thread.
If that still doesn't get you where you need to be, maybe you should start a thread specific to your blower controller's wiring ... if I come across anything else definitive to that end, I'll let you know.

[koan]

I've got a printed HVAC manual that is just the same as the library manual, same for all models.

I may be able to glean the setup / adjustment of the four principle levers from the 83-1xx series of documents - even though I have no intention of pulling the airbox or blower.  koan, I'll try your 'jiggling' advice directly on the cable control going to the defrost duct flap - provided I've identified it correctly.

I jiggled and got my flap free and immediately got it stuck again. After freeing it a second time I glued a limit stop to the HVAC box. Fixed the sticking problem but because the foam has gone the flaps are not fully effective.

there is one defrost ducts flap (aka "air outlet at windshield") controlled by one cable control attached to lever '17' (2nd from left/UP arrow symbol in my photo, illustrated on p's 3 & 4 in document '83-020.pdf' - "Operating lever for air outlet at windshield") on the L side, right?

Correct.

What else is going on at the L end of the slider controls pivot shaft?
Does the 10mm nut being loose at the L end mean lever '17' will not actuate?
Under what conditions (lever/flap positions) should it be tightened?

No, lever 15, heat mixing flap, 17 is the defrost vent flap.

The nut on the end of shaft clamps the heat mixing flap, not the vent flap. Assuming the setup is the same as the HVAC box heat is turned on by either heat mixing lever moving off the bottom stop, this actuates the vacuum valve on the firewall. The valve is either on or off, full hot water flow or no flow, the amount of heat in the cabin is controlled by the heat mixing flap, controlling the mix of heated and unheated air.   

It's in the manual but the nut is tightened with the flap in the closed position but with lever slightly up from the bottom. This ensures the vacuum switch can be closed to shut water flow off.

Should I expect to be able to get my hand in there on the L side to physically manipulate the cable control / defrost duct flap?

Can't on the HVAC box, not sure of the design of heat only box but I doubt it.

because the 10mm nuts on both ends of the slider controls pivot shaft were loose, and, I had initially mistakenly assumed I could sort things out from the R side, I've kinda' lost track of the various door position directions - document '83-100-2.pdf', page 6, step 66 & 67 show what to do with the R side ... only reference to L side found so far is step 12 on page 2 of '83-100.pdf' ... can anyone elaborate on overall lever setup / adjustment / door position directions?

Can't follow pages and steps, think you have posted wrong references. Adjustment and clamping of heat lever is the same on both sides. What needs to be elaborated on? 

... step 70 on page 7 of '83-100-2.pdf' talks about re-installation and adjustment of the operating lever for summer air (located directly above heater controls) - presumably this is unrelated to what I'm trying to sort out.

Same problem with references but correct, summer vent is fresh air (cooled air with A/C) and is unrelated to heat flaps.

Oh, and where exactly should I be looking to find the (presumably 2) drain holes associated with the 'ornamental grille on air inlet' (bottom of cowl area in front of windshield)

They are the two "elephant trunks" on the firewall, these are not the heater box drains. The heater box drains are small diameter rubber hoses going through the transmission tunnel near the firewall.

koan

[koan]

The only blower resistor I can find in the wiring book with 6 pin is the one for ACC, not sure what's going on if you have a heat only box.

EDIT: That's wrong, I wasn't reading the diagram correctly.

Wiring diagram in the library. Diagram 4 shows this resistor.

Don't know if this is any use but pins and colours are:

P1 Green/Yellow
P2 Green/Red
P3 Black
P4 Green
P5 Black/Green/Pink
P6 Green/White

If the colours match give it ago.

koan

[Frankenstien]

koan ... thank you for all the help and for being such a sport ...

OK ... so now that I understand lever 17's function, and, from reading your descriptions koan, I realize that even with the 10mm nut loose on the L end, my defrost vent flap should (and, I believe, does) still operate with lever 17 and what's jammed up on my car has to do with the intermediate levers on the R side (whose function / flaps control I don't fully understand yet).  I don't know why I thought the intermediate levers on the R had anything to do with the defrost, but then I didn't understand the meaning of the lever symbols initially either.

Regarding the intermediate levers, the manual says: "Set left-hand and right-hand heater operating lever [15's? yes?] to top position.
Move both intermediate levers (43) apart in direction of arrow [arrows - away from each other in illustration] and tighten nut (19) [being the 10mm nut at R end of pivot shaft in illustration]."

I'll have to see how that goes as far as freeing things up on the R side.

Essentially, once I have the intermediate levers situation sorted out, all I really need to be concerned with is proper adjustment of L lever 15 (as you outlined koan), clamping the L side in position with the 10mm nut, then repeating the exercise on the R side (I'm still a little foggy about the 10mm nut on the R end - which adjustment comes first, the intermediate levers adj. or the R lever 15 adj. or does it matter?)

BTW, even with my heat only box config., I can't get my hand in on the L side to physically manipulate the defrost vent flap.

Re: the drains,

"the two "elephant trunks" on the firewall" - I don't remember seeing them on the firewall from within the engine compartment, should I be able to, or, only from below the car?

"The heater box drains are small diameter rubber hoses going through the transmission tunnel near the firewall." - sounds like they'd only be accessible from below and would be tough to spot with the drivetrain still in place - do the ends of the hoses poke through a little?

FFF

[koan]

Lever 17 on the left with up arrow opens and closes defrost windscreen vents.

Lever 17 on right with down arrow opens and close footwell cabin vents.

The left and right 15 levers control the mixing of heated and unheated air to the left and right sides of the cabin. The driver can get hot air on his feet while the passenger gets cold air if desired.

The left and right heat mixing flaps are associated with lever 43 and nut 19.

As far as adjusting link 43 and nut 19 goes I think you have to suck it and see because after 30+ years of wear and disintegrated foam the book method no longer applies. Have to make sure the vacuum tap closes when both heat levers are down.


The "elephant trunks" on the firewall can just be seen on this image :

(click to get the big picture)

The LHS (furthest away) trunk is the black curved pipe hanging down directly above the rear most exhaust port. RHS is similar position but has a hose in front of it They may have fallen off but the holes will still be there !

The underside drains are hard to find, they do poke through, I know where they are but still have trouble locating them.

koan

[Frankenstien]

koan ... OK ... re (43) & (19) ... will have to suck it up and see ...

I found the "elephant trunks" on the firewall ... they were right in front of me ... I just didn't know what the H they were for ... a little bit of crap fell out of each one when I flexed open the ends (but not enough crap to account for complete blockage on either side).  Should I try forcing high-pressure air (or water? - bad idea?) through the mesh from above on each side while I flex the trunks open ... or perhaps just leave well enough alone?

If the two heater box drains are plugged, that would more than likely account for the rainwater dripping down into my passenger footwell from the center seam of the black plastic round ducting encasing the blower motor.  I'll have to get under the car with a good light, some soft copper wire and see what I can find / unblock.

Thanks again for all the help and explanations koan.  FFF

[joshm]

Thanks for the reply!

are you talking about the back of the combination cable / electrical knob in the center of my photo?  

Yep, that's the one

I tried to photograph the wires / connector of the main blower controller knob (assuming we're talking about the same thing) while still in place ... my camera's pretty small and I did manage to sneak it in and under, however, the (super-macro w LED settings) photos don't show what you need to see.

Rats. Thanks for trying.

I think koan has provided you with some info in a reply directed at you in this thread.

The colours don't match unfortunately.

If that still doesn't get you where you need to be, maybe you should start a thread specific to your blower controller's wiring ... if I come across anything else definitive to that end, I'll let you know.

Yeah, I'll do that.

The only blower resistor I can find in the wiring book with 6 pin is the one for ACC, not sure what's going on if you have a heat only box.

Wiring diagram in the library. Diagram 4 shows this resistor.

Don't know if this is any use but pins and colours are:

P1 Green/Yellow
P2 Green/Red
P3 Black
P4 Green
P5 Black/Green/Pink
P6 Green/White

If the colours match give it ago.

Thanks koan, but the colours don't quote match up as far as I can tell. I'll take a second look and give it another go, and also start my own topic with photos. Even once I get this problem sorted there is plenty more to do before I can say the heater works as it should! 

Josh

[joshm]

FFF,

I know it's a long shot and a big ask, but assuming I don't get anywhere with a new thread and hit a dead end, how would you feel about popping your heater controller out and having a look? I could provide step-by-step photo instructions...

joshm

[koan]

Doubt if the elephant trunk drains and the cowl area would be blocked unless you live in an extremely dusty climate. Just play a hose on the grille and see if it comes out the drains.

Water in the footwell can also be leaking windscreen seal.

koan

[koan]

the colours don't quote match up as far as I can tell. I'll take a second look and give it another go, and also start my own topic with photos. Even once I get this problem sorted there is plenty more to do before I can say the heater works as it should! 

I was wrong about the 6 pin blower resistor and ACC.

if you give me the six colours you have I'll go through my diagram collection and see if anything matches up.

When I've had connectors separate in the past the wires usually retain there relative position and bends and I can usually work out what goes where.

koan

[joshm]

the colours don't quote match up as far as I can tell. I'll take a second look and give it another go, and also start my own topic with photos. Even once I get this problem sorted there is plenty more to do before I can say the heater works as it should! 

I was wrong about the 6 pin blower resistor and ACC.

if you give me the six colours you have I'll go through my diagram collection and see if anything matches up.

When I've had connectors separate in the past the wires usually retain there relative position and bends and I can usually work out what goes where.

koan

Hi there, so as not to detract from Frankenstein's problem I've started my own thread, although my appeal to Frankenstein to take a look still stands! 

Thanks, joshm