question on heater controls

repoman · 08-02-2003, 08:28 PM

I was putting the console back together on my '84 and what a cheap piece the heater-vent matrix is! Anyway, I've got a couple questions on the function:

When slider is on "defrost", virtually no air to windshield vents. Cable linkage seems ok. Is this normal?

With AC off air temp from vents can only be adjusted from warm to very hot. Heater control acuator moves about 1/2" Once again, is this to be expected?

AC on, very cold air from vents.

I guess vent function is fan off, windows & sunroof open!

thanks

Pike · 08-02-2003, 09:29 PM

I have a 924, so this might not be accurate, but here goes:

_ All of the levers should go the same distance. If one will not, it sounds like the coolant valve may be stuck open. If it was closing the air would get cold. The valve is a very small inexpensive part. With a helper your should be able to diagnose the heat valve, and it is really easy to replace.

_ With my car, to get defrost from the windshield vents, I need to put all of the console vents to the right position (handily labled defrost).

_ I will agree with you, the lever box is really cheap. If anyone has one for a '77 924 for le$$, I might be in the market.

pearldrum · 09:55 PM

I too have the constant heating problem, where is the coolant valve located?

There is a vacuum controlled valve that connects to the back of the intake manifold that I know is broken. I was wondering if that was it?

repoman · 08-03-2003, 08:07 AM

after thinking about it overnight:

temp control cable was badly bent at slider end, I clipped about 2" off. probably not getting full range of travel on valve

probably need to replace cable but in interim I'll just disconnect at heater valve (pearldrum, look at rear of inlet manifold & down)

I really don't want to tear console apart again

I'll check defrost flap & see if it's connected. seemed to be at 1st glance.

With center vents shut windshield does get hot; guess i won't know for sure until winter

thanks

BlueQuestTSi · 08-03-2003, 09:25 AM

The coolant valve is located between the engine and the firewall, just about direct center. It's easiest(for me with big hands) to reach it from the passenger side. My cable was busted at the valve, just slide the valve lever to the passenger side of the car, and that shuts off the hot water flow to the interior core. I put some nylon zip ties around it, and stretch them to the rear motor pulling 'eye', I don't know if they'll go back to open when the engine is running and pushing coolant through the hoses(I just didn't want to be driving down the road, and get a sudden blast of heat).

The valve itself is fairly cheap, I've seen them for $15-20-ish on Pelican.

Just about every cable mount on my heater control is busted, and has been jerry rigged back together...... Cheap plastic, but then again, what do you expect from a 20 year old car....

pearldrum · 08-03-2003, 09:53 AM

I think I just confused myself last night. I hadn't heard it called the "coolant valve", just "heater valve" etc... The part that I mentioned was broken connects to the head and has something to do with emissions... Today we clamped the hose going from the coolant valve closed to see if that does anything to stop the air...

BlueQuestTSi · 08-03-2003, 04:30 PM

Quote:

Originally posted by pearldrum
I think I just confused myself last night. I hadn't heard it called the "coolant valve", just "heater valve" etc... The part that I mentioned was broken connects to the head and has something to do with emissions... Today we clamped the hose going from the coolant valve closed to see if that does anything to stop the air...

Bah, coolant valve, heater valve, we know what you mean

After all, it may shut off the heater(heater valve), but it does so by shutting off the flow of coolant

pearldrum · 08-03-2003, 06:06 PM

yeah, after we clamped off the line it stopped blowing, the air is even cool! Just ordered the valve from pelican.

Pike · 08-03-2003, 06:24 PM

Stopped blowing or stopped blowing heat?

Glad this helped!

pearldrum · 08-03-2003, 06:26 PM

Stopped blowing when the knob was turned off, I didn't try turning on the heat, but it probobly won't get hot with the clamp on the hose...

repoman · 08-03-2003, 09:23 PM

I had a brainstorm last night. As my cable is too short and I have no desire to change it because then I'd have to remove console (again)

But I'll remove heater control valve, check it's operation and then fabricate a small extension for for the operating lever on the valve

on a related note: what products besides 924/944 did VW/audi use the early heater control matrix on?

BlueQuestTSi · 08-04-2003, 07:19 AM

Quote:

Originally posted by repoman

on a related note: what products besides 924/944 did VW/audi use the early heater control matrix on?

Our door handles are the same as those on a Rabbit, we may try looking in one of those

SoCal Driver · SoCal Driver's Garage

Not much room to extend the arm on the heater valve. Most likely will hit the fire wall or the engine or the bell housing.

You really need to put the effort into fixing or replacing the bracket in the console that holds the end of the cable sleath.

The end of the cable sleath is held in place by the same type of clip that holds it on the valve. The catch on the plastic bracket breaks off and thus the clip will not "clip" any more.

If you look closely at the clip you will see that the sides are bent down to act as teeth and hold the cable sheath between the wire windings.

So some of the attempted fixes I've seen such as pull tie wraps just don't cut it for long if at all.

repoman · 08-05-2003, 10:22 PM

In my car there is about 2" between HCV arm and any interference; that should be plenty to provide an extension. The extension would be in place of the 2" of shortened cable. Visualize I'm merely substituting 2" of bellcrank for cable end; ie, I don't need any extra space. Extension will be at 90 deg angle to HCV arm. Simple piece of steel riveted to existing arm

The end of cable at control end is fine, clip is ok, cable has just been shortened where it was damaged. I just bent in new S curves

looked at a old Rabbit at work; heater/vent controls are the same!

My defroster flap lever is broken flush with plenum box. I'm not going to fix as I don't drive car much in winter. Dash is shallow enough and cockpit small enough that I think windscreen would stay pretty clear anyway. Maybe a cheapo electric defroster in glove box "just in case"

Figured out why AC is so effective with HCV partially open: When AC on fires a solenoid valve. This must be used to isolate hot air from underdash plenum. Now, that is one good idea they had!

I appreciate the feedback

BlueQuestTSi · 08-06-2003, 07:19 AM

What year Rabbit did you look at? I have a 70 something at a shop my neighbor owns, I looked at it yesterday. The controls look about the same, but the fan control was a sliding switch and not a knob. I thought about looking a little closer.

All of my knobs on the heater controls have the cable retainer busted, and have been 'rigged' up in one way or another. They don't work at all.

SoCal Driver · SoCal Driver's Garage

The windshield will get iced/fogged without the defrost working.

You can bugger up the heater controls all you want. The stock works just fine when properly maintained.

Better to extend the cable. Or just buy and replace the cable and heater lever support thingy. About $30 on eBay. Or even less at a friendly dealer.