Griff heater problem - Screen/feet control

[tvr_nut]

I have searched on PH, and found quite a lot on this subject, but nothing that quite fits the problem I am having.

I am having trouble with the heater control that directs the air to screen or feet. The problem seems to stem from the fact that the little pot that attaches to the gearbox shaft of the motor controlling the appropriate flap is loose.

Sometimes it is turning with the shaft, other times it walks itself to one extreme or the other (whereupon the heater control stops doing anything. Other times it walks itself out and hangs by the wires!

What is strange to me is what this little pot does - so far the most reliable operation has been achieved by:
1 - Taking the pot off from the end of the shaft
2 - Putting the dashboard control in the mid-range position
3 - Turning the pot with an electrical screwdriver until the limit switch arm is about midway between the limits

Having done this, moving the dash control seems to drive the heater flap from screen to feet, and can be stopped midway. Although the movement is far from continuous.

This makes me wonder what this pot actually does? And why is this one loose - the other ones on the fresh/recirc motor and the hot/cold water valve seem quite firmly fixed? Read something on a post about grub screws - has one come out or loose?

Confused! Any help appreciated!

[Ballistic Banana]

I dont think the motor should be turning. It should be stationary ad just turn the rod that goes into the Black plastic Box. All that is in there is a plastic Flap covered in foam that is attached to said rod.
That moves the air either up or down

BB

[tvr_nut]

Ballistic Banana said:

I dont think the motor should be turning. It should be stationary ad just turn the rod that goes into the Black plastic Box. All that is in there is a plastic Flap covered in foam that is attached to said rod.
That moves the air either up or down

BB

Sorry - my sloppy description (I knew what I meant!). I was referring to the motor whirring away and the shaft turning. That bit seems to be OK, and the two limit switches are doing their job. Its just the loose pot, and the confusion about why it seems to work when it is removed from the end of the shaft/rod.

(PS: I see you have replied to my earlier email - when Talktalk actually works for long enough to let me download my mail, I will stand a chance of replying. Bunch of w@ankers (but it is cheap).

[DarkMatter]

I posted some picture in this thread www.pistonheads.co.uk/gassing/topic.asp?h=0&f=9&t=312402 .

I glued the potentiometer back on to the motor, after I had worked out the settings required for the flap. All works fine now. If you are a TVRCC member there are some details on the TVRCC Griffith Forum here www.tvr-car-club.co.uk/forum/forum_posts.asp?TID=4631&KW=

[tvr_nut]

DarkMatter said:

I posted some picture in this thread www.pistonheads.co.uk/gassing/topic.asp?h=0&f=9&t=312402 .

I glued the potentiometer back on to the motor, after I had worked out the settings required for the flap. All works fine now. If you are a TVRCC member there are some details on the TVRCC Griffith Forum here www.tvr-car-club.co.uk/forum/forum_posts.asp?TID=4631&KW=

Thanks for the links - I too had considered glueing it back too. What surprises me is that with the pot set midscale, and left unattached to the motor (hanging by the wires), that the heater knob actually seems to control the flap. If it acts as a positioner, I would have expected some less well behaved operation.

I did not really notice a difference when I refitted it (and held it from rotating). Shortly after that I broke the while wire off, and gave up for the night.

Tonights job - upside down soldering in the footwell (not nice) followed by Evosticking in a confined space (not nice, but after a few lungfulls of solvent, will not care - WOW MAN!!).

Edited by tvr_nut on Wednesday 21st February 18:23

[tvr_nut]

Job done - not as bad as it might have been. No solder burns to TVR or myself, managed to keep the glue off the carpets, and mended little'uns Captain Jack Sparrow figure whilst the glue was out!

Can get back to replacing the duff cooling fan tomorrow.........

Ta for the help!

Neil

Edited by tvr_nut on Thursday 22 February 00:08

[tvr_nut]

Feeling pleased with self again after mending heater controls.

But had not realised that just because taking the glovebox out is easy, does not make it easy to refit it. Cannot see to line up the allen-bolts with the holes in the dash - so total luck and guesswork to get bolts back in.

And then have to be incrementally tightened up to ensure the little clicky-catch thing lines up properly.

Took a frustrating hour to do what I had thought would take 10 mins!

Have tried tightening the bolts a bit more to try and make it less susceptible to jumping open at the slightest tap of the passengers knee or pothole in the road.

Oh well, getting there slowly.........