Q: Front heater control box - positioning question

[Calnan]

'89 Carrera Coupe:

The cable from my lowest (red) slider on the dash controls to the heater control box in the front compartment behind the dash has come loose at the control box. The connection for this cable is at the rear of the box, and getting to it is really difficult (of course that's the one that would come loose!). But I think I can take a couple vent hoses off and get my hands in there to pull the cable and tighten the bolt.

Question is - with the red slider in the left-most position (toward the driver), what position should the metal valve arm on the control box be in? Mine is now pointing straight up (see picture), but before I tighten it, I wanted to check if it should perhaps be in another position, like "9 o'clock" instead of the current "12 o'clock".

Also, how freely should that metal arm move? If the valve inside is stuck, I obviously have another issue that tightening the cable wont fix.

Thanks for any help - it's my first time attempting this, so apologies if any of this is unclear.

- Mike

[spuggy]

Originally Posted by Calnan

'89 Carrera Coupe:

The cable from my lowest (red) slider on the dash controls to the heater control box in the front compartment behind the dash has come loose at the control box. The connection for this cable is at the rear of the box, and getting to it is really difficult (of course that's the one that would come loose!). But I think I can take a couple vent hoses off and get my hands in there to pull the cable and tighten the bolt.

The booster tower makes access a lot worse, I think.. I wanted to remove the driver's side ventilation flapper box from the floor to clean/lube it. I tried for a long, long, time (and more than once) to get the rear-most clip off, but could never quite get on it solidly enough to shift it. Nor could I figure out what the heck would. I eventually gave up and had a shop do it - because the only other alternative was to remove the mount from the trunk floor itself... Professional wrenches have tools, tricks and experience... Wrench said "yeh, it's a little fiddly". Bah...

By way of contrast, the bottom hood shock clip that folks complain about? 30 seconds with a pair of long nose pliers and a small screwdriver. Took me much longer than that to retrieve the small screwdriver after it leapt to freedom down the side of the gas tank afterwards Removing the electrical portion of the ignition switch leaving the lock in situ? Eh, I'd have drilled the darned bolts out if I'd had a drill - but I didn't, car was broken down on my driveway and I wanted to go somewhere - that was only 30+ minutes of claustrophobic (and uncomfortable) yoga with your head on the pedalbox.

I think the driver side ventilation flapper is an absolute pig to remove... The clamp on the cable arm is a little awkward to get at, but a 2-3 minute job once you get into position with tools within reach...

Question is - with the red slider in the left-most position (toward the driver), what position should the metal valve arm on the control box be in? Mine is now pointing straight up (see picture), but before I tighten it, I wanted to check if it should perhaps be in another position, like "9 o'clock" instead of the current "12 o'clock".

Heck, I've got no idea, and I spent hours turning those things over and around trying to visualize how/what they did.

Don't overthink it. Here's how I did mine:

If you have a helper, have them move the dash lever around while you watch if the exposed piano wire gets shorter or longer. I'm presuming they're going to pass on getting in the trunk... Although if you have children, they'll probably find this job easier than you will....

If you don't have a helper, put the dash lever in one position.

Put some tape on the piano wire, or mark it with a marker or a scribe. Put the dash lever in the other position.

Is the end of the piano wire extending from the sheath longer or shorter now?

If longer, put the valve lever on the box furthest from the cable clamp; e.g. so that there is the most cable between the clamp on the box/end of the cable sheath and the clamp on the lever.

If shorter, put the valve lever on the box in the position that put has the least cable between the clamp/cable sheath and the clamp on the lever.

Job done. It's really not a very precise setting. Just don't whale on the dash lever at either extreme and it'll be fine. You'll probably realize 5 years later that you set the lever where you wanted it and pretty much haven't touched them since, apart from the panicked reaction when you closed the driver's window in the rain and then couldn't see through the windshield 90 seconds later... (Hint: the fan lever is the one if this happens. Messing with the other levers just doesn't help fast enough).

Oh, and any more than 1/4 turn on the clamp nut once you detect it starting to nip up (it's fairly subtle) is pushing it. You'll never feel the bolt stretch, they just break. I had to stop and buy several spares - so of course, I've never broken one since...

Also, how freely should that metal arm move? If the valve inside is stuck, I obviously have another issue that tightening the cable wont fix.

The valve inside should move very freely. If you get the box off (yeh, the others were easy - but they weren't stuck), it'll bang open/shut under it's own weight (it's plastic) as you turn it over to try and puzzle out what the heck it does... Think the valve may once have had some kind of foam edging sealing the seat. But that'll be dust by now.

I had hoped to be merely lubricating or freeing off the piano wire cables. Once they were disconnected from the dash levers, I knew it wasn't going to be quite that easy, because all the resistance was inside the plastic boxes with jammed-up, broken or misplaced valves...

Good luck!

[Calnan]

Spuggy -

Huge thanks for the quick and detailed response!! I really appreciate it. I will crack things open a bit more tonight and hopefully I can make some progress. First trick will be to figure out whether the valve inside the box is stuck or not - that will dictate next steps, as you describe. I do have some lightweight kids that can crawl in the front trunk to be my helpers while I'm inside the car! Thanks again - I'll let you know how it goes!

- Mike