Stephen Irons

Hi

I havea heating issue on my 1978. A month ago the Bowden cable that controls “Heat” became unattached at the control lever – the small plastic retainer had broken - under the centre console. I have managed to re-fix the cable with a small bracket and it appears to be working perfectly. However, since then I do not seem to be able to get it blow cold air at all when the lever is moved to the “cold” position. The A/C is currently non functioning, so I know that it will never be “chilled”, but it did used to blow un-heated air on anything but a really hot day.

As I understand, the cable goes to a flap/door in the heater assembly and closes this off as it is moved towards the cold setting. I am wondering if when the Bowden cable came adrift, it may have detached itself from the flap operating lever?

So, this long winded post is to ask if it’s possible to see the flap lever if the glove-box is removed? Based purely on looking at the manual, it seems to be in the area behind the glovebox, but before I get into removing it I just wondered……. ?

Additionally, am I right in thinking that the vacuum operated valve in the heater water pipe is only operated when the “A/C-Vent/heater/defrost” lever is moved across to A/C – is that correct?

jotto

Stephen,
I posted something very similar a few days ago. I was playing to see if my air con worked and after checking all vents were working etc I moved the lever from cold to hot. Immediately got warm air from the vents but when I moved the lever back to cold, I didn't feel any resistance and still had hot air flowing.
Not sure where my cable has come adrift yet but apparently yes you can get to the valve with the glove box removed.

Hopefully I can simply move the bracket by hand for now to get cool air again.
Just another job to add to the to do list.

jotto

Having trouble editing on phone.

https://www.corvetteforum.com/c3-tech-performance-3/showthread.php?t=3510866

Stephen Irons

Hi Paul

Thanks! Yes, I admit to not doing a search first! Ooops! Perhaps I should have posted on the CCCUK forum!

I'd looked at the AIM and had an idea that the “far end" of the cable would be visible if I removed the glove box. So, yesterday evening I did that and indeed it is, if "shrouded" in wool insulation!

Some close examination showed that the end of the small lever did not appear to push the vacuum switch in completely when the control lever was pushed fully to cold. I don’t believe that it is broken, but as it has only recently stopped functioning it may have. However, I made up a small “pad” that I slipped over the lever end.

I did spend a bit of time re-adjusting the cable with the screw assembly, and it now appears that when the lever is pushed fully to the cold position, that the switch under the dash is fully depressed. So, we’ll await the next outing to see the effects!

Incidentally, the initial problem on mine was that the small lug on cable casing had “popped out” of the slot in the lever assembly, due to the “tang” breaking. When I moved the lever there was no resistance at all! So I made a small metal bracket that holds it in place. I did take the opportunity to squeeze some WD40 down the cable case, which has made operation much lighter. All the "under dash" stuff is easily accessible with the centre console passenger side carpet panel removed.

The other job that I had done years ago was to sheath (and seal) the tiny vacuum line to the under bonnet valve with clear flexible tubing. The original is brittle and was cracked, so leaked, meaning the valve didn’t close. Not only did it mean the valve worked, but the car ran better – clearly the vacuum leak was enough to affect the engine!

jotto

Glad you got it sorted! Perhaps I should get on with mine. I have an ever increasing list of jobs to do.

If I start with the simpler ones and get at least some ticked off it may spur me on.