R129 HVAC display/control unit

[ShayneJ]

the LCD in my SL's HVAC has a fault where on switch on
all good but after 10 seconds or so the display starts to flicker
then fade out all but some random segments.

does anyone know to a fix or where i can get a replacement
unit in the south central area?

 

[renault12ts]

Ebay,

 

[ShayneJ]

Ebay,

Scoured the bay with no joy closest i could find was a unit
for an E class no use as its a dual zone unit mine is not

 

[Sp!ke]

I think there's a fix to this issue out there on the internet.

I seem to recall that the cause was some dry joints on a connector that could simply be re-soldered.

 

[renault12ts]

Scoured the bay with no joy closest i could find was a unit
for an E class no use as its a dual zone unit mine is not

Try the on line breakers.

 

[EDZ649]

Try ebay.de and use google translate.

 

[BTB 500]

We had a similar issue with the climate control unit in our 1996 Audi. I took it apart and was able to find some fractured solder joints on the back of the PCB:

I think this is quite common due to hot/cold cycles, vibration, etc. over the years. 5 minutes to fix, if you have a small soldering iron and a steady hand!

 

[ShayneJ]

We had a similar issue with the climate control unit in our 1996 Audi. I took it apart and was able to find some fractured solder joints on the back of the PCB:

I think this is quite common due to hot/cold cycles, vibration, etc. over the years. 5 minutes to fix, if you have a small soldering iron and a steady hand!

Yep the board is in quite a state im going over it now with a hot pen
a soldering iron and weak hope

 

[andy27168]

The fault you describe is very common, and may explain why there are a lack of second hand spare items. The 202 is the same as the 129 (both single zone) I did manage to find one from a low mileage C43 and within a couple of thousand miles it was the same as the one it had replaced.
When the display goes a light flick with my finger nail normally sorts it out.
If you can find the area of the PCB that controls the LCD display that needs the resoldering please post.
I still have my old unit so I may have a look at this over the holiday period myself.

 

[ShayneJ]

bit of an update after heating soldering and faffing around
nothing seems to work. as i said my unit was in a poor state
in that it seems the board had not had any of the sealing lacquer
applied that i am used to seeing automotive circuit boards
coated in to protect from damp etc.
so there was a fair amount of corrosion on component legs etc
and eventually i found one leg had corroded right through
in such a way that unless you looked at it just right
you couldn't see it!
on the display driver chip at the rear left of the board
so with some "very" delicate cleaning and soldering
i now have a working display again ( for now )

 

[BTB 500]

Good work!