front blower heater control re-install

[hellblau82]

Hi guys,

ive just re-installed all my heater control units including the 3 wires that connect to all the units.

I think I have all the correct cables connected where I needed them but using the heater control its self the knobs feel like when the wires shift they bow and don't operate the flaps in the components correctly.

is there a good guide how to re-install this correctly...can the heater cable wires go bad??

ive tried to get it right three times today and has given me the complete ****s..

help

[DRACO A5OG]

Unfortunately, none that I know of. I assume you did not take any pics prior to disassembly, I know it is a real PITA under there working upside down.

My 2 cents, I would remove the frunk cardboard and as a helper to play with the controls to see which cables are binding or not operating properly and make adjust there.

[uwanna]

Adjusting the cables for correct operation is one of the most frustrating things I have ever done on my car. ARG!!
Read this thread, some good hints and tips to get things moving smoothly again.
Good luck! 911 SC Climate Control Bowden Cables

[T77911S]

i don't know about your car but I just messed with mine in my 930.
if the cables are bowing you could have 2 that are "fighting" against each other.

with mine. the box on the drivers side was like a master. it was controlled by the cables. then the cables from the master box controlled the slave one on the passengers side. so each flap of the master had 2 cables, one from the controls then one that controlled the slave.

porsches aif flow system is as bad as BMW's cooling hose system

[Jonny H]

it sounds to me that one or both of the cables that connect the left and right hand vent valves is at the wrong end of the adjustment.

Start with front lever on the right hand side mixing valve. Disconnect the incoming cable from the cockpit. Now, you should be able to manually turn the lever on the valve and the left one should follow suit. if it doesn't, then adjust. Put the cabin levers so the cockpit cable inner is fully extended and connect the valve back up with the right valve lever also fully extended.

Do the same for the rear valve (much harder to get at)

[Dpmulvan]

I had trouble with the valves being really stiff, If I remember correctly I sprayed some lube on them. PO had forced controls and broke the plastic heater control housing, replacing was a huge pain!!!! Whatever you do don't force levers!

[hellblau82]

Originally Posted by Dpmulvan

I had trouble with the valves being really stiff, If I remember correctly I sprayed some lube on them. PO had forced controls and broke the plastic heater control housing, replacing was a huge pain!!!! Whatever you do don't force levers!

what are you calling the valves?

[gazzerr]

It's frustrating and takes a while to get right. You have to adjust the cables so that the flappers in the distribution boxes are perfectly synchronized across the full range of lever travel or it will bind up. Start with all the levers in the left position.

You have to loosen up the pinch bolts on the distribution box "L" levers and then move the dash levers all the way to the left being careful that the cables don't come out of the bolt hole (PITA to put back trust me - the bowden clips are even worse - that was a battle). Make sure all the air flappers are at the end of their travel for the dash lever's left position (you can watch what the cables want to do and easily work out what position they should be in). I then tightened the pinch bolts. I found I had to loosen and retighten the cable pinch bolts to the passenger distribution boxes to remove any residual cable tension once I had the driver's side adjusted properly.

G.

[hellblau82]

yeh ok I seemed to of got the first two levers working ok its the third red lever which I am having a nightmare with it just doesn't want to operate properly.

its a different sort of lever on the heater control itself

it connects to the rear of the master flapper box I believe but its just not happy tried for another few hours today I'm wondering I need to order a new cable

[javadog]

The cables usually don't go bad but they may need to be cleaned and lubricated. They are just a piece of wire in a Bowden housing, so there isn't much to go wrong. The two distribution boxes can be removed from the car as a unit, with cables attached, and the two cables that link them can be adjusted on the bench. From there it's not hard to put it back in and attach and adjust the other three cables.

JR

[hellblau82]

Originally Posted by javadog

The cables usually don't go bad but they may need to be cleaned and lubricated. They are just a piece of wire in a Bowden housing, so there isn't much to go wrong. The two distribution boxes can be removed from the car as a unit, with cables attached, and the two cables that link them can be adjusted on the bench. From there it's not hard to put it back in and attach and adjust the other three cables.

JR

Not that hard!! Haha only thing else I can think of is if they are not connected/clamped down properly behind on the heater control unit itself?? The wire is still just bowing

Can anyone provide some photos of there heater control units I can't find anything on google lots of front shots but nothing of the control arms at the rear and how they are suppose to be attached.

Once the Bowden cables pass through into the frunk is there a specific route they need to travel or held in place or do they just loop straight in onto the distribution boxes?

It operates ok when I don't have the distribution box screwed into its position and the Bowden cable not bending so much but minute I put it back into position it seems crap itself and lever not feed back inside the tubing like the cable is warping.

I will continue to try more variations

Any photos would be amazing

[Dpmulvan]

Try spraying some silicone on the flapper pivots, that helped with mine. These where only photos I could get quickly early in the morning on an 8 degree day, I'll try to get some more when I heat the garage up.

[javadog]

Originally Posted by hellblau82

Not that hard!!

Nope, it's not. But, people often make it that way, trying to shortcut the repair.

Why do cables bind? Well, four things come to mind. They are routed incorrectly. They are poorly lubricated. They get rusty and the housings deteriorate. The things they push and pull need lubrication.

If you had your controls out of the car, one thing you should have done was to clean and lubricate the levers and clean and lubricate the cables and housings. If you didn't do that, well, don't expect miracles.

How to route the cables? Don't ask me for a photo (maybe you should have taken a few of those before taking it all apart) but instead, take a look at the path from A to B and see what routing makes the most sense. Install them so that they are curved the least. Install them in the way you think they should go. Have a look. Does there appear to be a better route? If so, change it.

It doesn't take all that much work to remove all this stuff. The hoses are attached with hose clamps. Easy off. The blower housing is held in place with a couple screws. The distribution boxes are held in place with a couple screws. While you are screwing around trying to adjust a cable you can't even see, I can have all this crap out and on a workbench. Why?

Well, how about lubricating all the flapper valves? They weren't lubed well at the factory and it's been 30 or 40 years. Think they are well lubed? Take the two interconnecting cables apart. Clean and lube those. Then, install them again and make sure they work in concert with both valves. When you put them back in the car, attach the cable from the dash to the backside before putting them in place. That way you can get to it easily. Then, install the front cable. Then, put the blower housing back in and install the cable on that.

How to adjust a cable? Figure out what it does. Move a lever, watch the cable movement, figure out what it's supposed to be moving. If you move a lever all the way one direction, put whatever valve it operates in the position that it should be in when its lever is in that position, then you clamp the housing in place. Done.

Sometimes you shoot yourself in the foot by trying to pick at it a little at a time. It's often faster to just bite the bullet and do it all and never have to screw with it again.

Not to mention, while you have all this crap out, you can have a look at the foam seals on some of the flapper valves and replace them, if they are bad (guess what, they will be.) You can also play in the Porsche parts bin and improve some things. You'll note that you can build a system that will allow you to completely block off all fresh air into the cabin if you've removed the A/C (assuming your car had that) or run a nice amount of fresh air to the dash vents if you want that. These systems have been plumbed a number of different ways and there's all sorts of things you can do with one, once you understand how everything works.

JR

[gazzerr]

From memory the red one was the easy one for me because it's only moving one flap. I think you just need to get someone to move it while you watch and see where it's binding up. Take JR's advice and remove the blower box from the car so you can go right through it and lube it all up. Mine was missing a circlip from the rod that actuates the flap too. Here's some pics I had when I took it apart. Note the steel rod on mine was loose before I fixed it.

[hellblau82]

Originally Posted by gazzerr

From memory the red one was the easy one for me because it's only moving one flap. I think you just need to get someone to move it while you watch and see where it's binding up. Take JR's advice and remove the blower box from the car so you can go right through it and lube it all up. Mine was missing a circlip from the rod that actuates the flap too. Here's some pics I had when I took it apart. Note the steel rod on mine was loose before I fixed it.

Wait the red dial was controlling only one flap

Currently the cable for the red knob runs to the rear of the first master distribution box..

Is this incorrect??

[Jonny H]

Top left slider fresh air amount. Single cable to front of blower housing.
Middle slider fresh air up/down. Cable to right hand blend valve, front. Extender cable across to left front.
Red slider heat up/down. Cable to right hand blend valve, rear. Extender cable across to left rear.

Trust me, I know the system inside out as we're designing a replacement for it.

[hellblau82]

Originally Posted by Jonny H

Top left slider fresh air amount. Single cable to front of blower housing.
Middle slider fresh air up/down. Cable to right hand blend valve, front. Extender cable across to left front.
Red slider heat up/down. Cable to right hand blend valve, rear. Extender cable across to left rear.

Trust me, I know the system inside out as we're designing a replacement for it.

Yep ok I had it all correct then..I'm just guna go ahead and say please if you do design something let me know because this system is a piece of S$)T!

At this Stage ..i have the red slider somewhat operating only on one side it still seems to just want to bend bow and not operate properly my cars auto heat function is completely Broken anyway so at this I don't really care now.

On the centre auto heat unit there was a cable that traces up the A piller and into the headlining with a sensor on it that i can't replace because it's a part that's no longer manufactured.
It was destroyed when my 911 caught fire.
Anyway thanks for everyone's help

[hellblau82]

I have fresh air I can distribute between foot wells and dash that was most important

[gazzerr]

Argh sorry for the bum steer the top lever is for the blower (one flap) in the blower box, the middle lever is the cold side of the distribution box (front of the flappers facing the frunk) and the red one is the rear cable on the distribution flappers (closest to under the dash). When you posted the pic of the blower box I got fixated on that.

If it's not binding when you disconnect the cable and lever moves freely then your distribution boxes are not properly synchronized. You can pull the tops off the distribution boxes and watch them through the full range of travel as you move the lever. They must be in exactly the same position on each one as the lever moves when you open and close. Careful removing the clips from the boxes they can fly off like a bullet. It's just a matter of getting it right.

Are all the bowden clips present? There's supposed to be one each of the L brackets end where the cables actuate the flappers. It will bind because the cable will flex without them. That's 2 clips per L bracket.

[Knight77911]

I'm replacing the heater controller today. About that routing...any tips. I'm not worried about adjustment of the cables, lots of great tips here. I'm terrified about getting the cables under the steering column and up and out through that grommit. Yikes. Any tips on that?