Dual Heater Dials - heater matrix???

Right, have a problem with the heater system on my 1996 300tdi XS.

The drivers side heater dial works fine - goes all the way round from cold to hot and the temp works accordingly. However the passenger side dial only turns about a quarter of what it should – only goes from vertical to around quarter past 3ish mark…so no cold air will come out of the vents, nor really hot.

I have had the dial part out of the centre console, and checked that, but once out and free from the disco, the dial turns all the way without a problem, so I am guessing it’s the actual heater matrix, but wondered if anyone else had this issue before, and if they fixed it without having to remove the whole dash etc to get to the matrix?

Cheers for any input.

Something simple like a sticking cable or damper control arm may be.

cheers for that - are these easy to get to, and if so, what does the damper arm look like?

Nope not easy to get to, but with a torch look under the dash while operating the drivers side dial (U may need a little helper) and you will see the arm moving u will have to move cables to see.
As any one been touching things behind the dash, fitting a radio etc.?

mmm, I did fit a radio a while back....is that where everything is, as also fitted a parrot, and they have a lot of wire to hide - wonder if its all that, that is blocking it.....will have a look with a torch

That could be it as I fitted a new headunit a few months ago it had a birds nest of wires which I stuffed away, job done.
A few weeks later I moved the controls to hot and only one would go round fully.. so I removed the headunit and did a neater job with the wires.. that sorted it, the control now works as it should.

May be a daft answer/question but did you put the heater nob back on the right way? There are two ways it can push back on (or there are on mine!). I had the panel out of mine a week ago cos the air vent direction cable was disconnected. When i put it all back I found that one of the heater controls would only turn about a quarter of the way - pulled it off, turned thru 180 degrees, put it back and it was fine.

Edit, just noticed you sorted it anyway!



Ah'll get me coat..

not sorted yet - going to pull out the radio and the mass of wires behind it tonight to see if that sorts it out.

As for the knob being on the wrong way, I am sure this did work, hence I got a new panel to try first, so I reckon I have it on the right way, given 'I think' it worked when we first bought the disco - but something else for me to check out if the radio and wires are not the problem

Try whipping yer knob out first cos that should only take a mo!

sp33der said:

Try whipping yer knob out first cos that should only take a mo!

Click to expand...

Wot and then he tries the heater after wards

my knob was fine

I had put a couple of crossover boxes in for the tweeters, and that was the problem, the arm was catching on one of the crossovers

Many thanks Discool for putting me in the right direction

Glad I good help Stu.
This is the stuff I had to stuff away plus a cable for the underseat CD player, most of it is under that headunit support bracket now and laying behind the dash somewhere

I know the feeling, having most of that wiring too, also the Parrot wiring, and then 2 alpine crossover boxes about the size of a large matchbox each - why do they need all these wires and boxes.......