Hi,
I have the 1996 A4 - B5 with 2.6l v6.

well i have also come across the problem of no dash illumination / instrument cluster lighting when the park lights are turned on, means cannot see dash instruments at night. Just by googling a lot of posts about audi dash lights appears to be common, but little in the way of actual repair.

On the far left bank of dash switches is a brightness adjuster, dismanltled and measures all ok. As the small pot in the dash appears to only to be used to give a ohm reading and not current controlling, I would assume somewhere else is another circuit with maybe a transistor that adjusts the dash lights brightness.

Is there any control box for this under the dash? Or is the dash illumination built into the dash board circuit board?

Attached is a photo of the component side of the dash, Id like help to identify which pins on each dash connector block and label what they are used for.\,

Has anyone found any common problem with dash lighting failure

thanks

 

Does anyone know if the dash illumination lights which includes the lighter/ashtray light circuit are fed off a relay or whereever from?
thanks

 

For safety for night driving, a way around the problem circuit would be to fit new led's in place of the old bulbs, bypass the circuit board illumination circuit, and wire behind the dash a fresh circuit of LED's and wire that to the park light wire on the headlight switch on the steering column.

 

This may be a dumb question... but are you certain that the dimmer switch is tuned up? These cars' dash dimmer switch is (I believe) the left ****/button on the front of the guage display. One should set the time (when turned) the other should reset the trip meter (when pushed and held) and should change the brightness of the lights when turned.

 

When I purchased my current 12v I had a similar issue. I had no need to pull out my cluster but did happen to blow an easy to change fuse.

 

HI,
thanks, no not a dumb question.
I did find several blown bulbs on top of the dimmer switch being turned down.

I think its a poor design flaw and safety flaw that the entire dash lights can be effectively turned off at night by accidentally or otherwise turning down the dash light level via the dimmer switch.

My curiosity about how it all wires together is to see where i can put a limiting resistor in line with the dimmer to limit the low light dash light level so that they can be dimmed a bit but never turned off completely via the dimmer, i suspect the dimmer circuit may be part of the dash circuit board, but im not sure.

Part of the challenge is that full service manuals and electrical diagrams only appear to be available for purchase rather than being openly available information, so unless one has those it can be a guess to what is wrong where.

please to say tho, all lights working again and dash fully reassembled

 

Please share on how you fixed it,these forums are for such situations,where someone has found a solution or fix and posts it,so for someone else,having the same issue,knows how to fix it. Simply posting..."all lights working again" isn't helping anyone that may have the same problem,so say everything is working again,then follow up with how you got everything working again.

 

Hi Gee off 2121
"These cars' dash dimmer switch is (I believe) the left ****/button on the front of the guage display. One should set the time (when turned) the other should reset the trip meter (when pushed and held) and should change the brightness of the lights when turned."

yes good point, new owners may not be aware of the dimmer on the guage display.

Hi Morpheous
How i fixed the problem.....using a multimeter to check every dash light bulb and replace all blown ones with fresh bulbs, except for the lighter/ashtray which was replaced for a white LED.

One quick way to test the dash light dimmer circuit is to put a multimeter across the light for the ashtray/lighter - brown(-) and grey/blue (+) when the parks lights are turned on;

when dimmer is turned fully down, voltage will be near or at 0, sweep the dimmer across its range with park lights on will see a change in voltage across those dash light wires, it simply checks whether the dimmer circuit is working or not, as I found the circuit was working next step was to check / replace any blown illumination bulbs (in the photo first post, the dash cluster illumination bulbs are the ones with white holders including the gap where one was removed)

cheers

 

Hi,
to add an adendum to the above.
Initially I had no dash lights at all. After the bulb changes, I now note that at lowest dash light dimmer setting, the backlights are barely visible. That tells me something:

When putting a multimeter across each of the illumination light connections on the dash circuit board so far it appears that most of the dash lights are in parallel - possibly except (i may be wrong...) for the illumination light for the mileage record/trip counter panel display.

Either there was a poor connection somewhere that has now come right with the removal/reconnection of the loom plugs to the dash or else i suspect that one bulb may be responsible for all lights failing to light, without a circuit / dash lighting diagram i dont really know the full answer yet.

Kris Audi Page for 96/97 audi i found useful to find out how to remove the dash instrument panel:
http://audi.kris-hansen.com/cluster_bulbs.htm

 

I have intermitent issues on the dash - going to try all of the above at the weekend. Thanks for the "how to take dash cluster out" link - invaluable.