Autocheck for lights

[Tonks4x4]

Just a quick one, I have wired in the autocheck system into a cabriolet from an S2. It keeps giving me a fault on bulb out. Does the autocheck test the reverse light bulbs?

I had this problem 5 years ago when I did the same on another cabriolet and never got to the bottom of it.....

I would like to cure it on this one if anyone has any pointers....

[Nuvo]

You could probably answer part of this one yourself, unless I've missed the point. Why not try removing the reverse light bulb from your S2 to see if AC gives you a bulb warning?

Looking at the schematics, the reverse lights are *not* checked by the bulb monitoring device J124.

[Tonks4x4]

what a fool! I did not think of that. However every bulb on the car is functioning but i am still getting the bulb failure warning. Is the check unit (j124) different part number from cabby to s2? And no i have not got hid's fitted as i know this causes the same issue.

[Flat on my back]

.

Thought the AC worked on a reading of <> ohms, so always hard to find when a warning is flagged but no bulb is out?

Maybe current draw also?

[Nuvo]

From memory, the bulb monitoring device will share the same part number *unless* the cabby is fitted with the third brake light in the boot lid. Have you wired 6/58R and 5/58L of J124 back to each light board? Is 8/31 grounded to the rear wiring loom?

Just a few things to check.

[macspring]

My 1999 Cabby v6,

has HIDs and has recently started to throw up the fault light on the Autocheck, if that's of any benefit?

Kind regards.

[topsparky]

has HIDs and has recently started to throw up the fault light on the Autocheck, if that's of any benefit?

Kind regards.

thats because on hids mate
the auto check does n't
get the right value so throws
up the bulb failure

[Phil Payne]

If it's anything like the ur-quattro (voice) or the Type 43 or Type 44 it's a kind of open Wheatstone bridge.



It outputs a signal on k if there is no voltage drop between either of the silver-bridged paired pins OR if the voltage drop present is significantly different. On Type 44s especially this means changing BOTH brake bulbs if one blows, because the old bulb/new bulb differential current triggers the thing.

[johne]

The front autocheck light unit checks the two dip beam headlights.

The rear autocheck light unit checks the brake lights and rear tail lights.

No other bulbs are checked so, no the reverse light isn't covered and isn't going to be the cause of your problem but if you have a central brake light, that will upset the system if the central bulb(s) is connected in parallel to one or the other of the side brake lights. You need to make sure the central brake bulb is connected directly to the brake switch before the rear autocheck unit, not after the autocheck unit.

See wiring sheet 34/3 in S2central.net wiring pages.

John

[Tonks4x4]

Hi all thanks for the replies. I have had to do the family thing today so not had a chance to play....

There is no 3rd brake light so it's not that.

I will be back on to it at 8 in the morning.

[breitling]

I have the same issue so please share if you come to a conclution.
I have a central brake light though...

Maybe its possible to de-connect the whole autocheck for lights?

[Tonks4x4]

the checking unit in a coupe is in the rear left hand side me the boot between the body and the outer wing. I am not sure where it is in the avant. I looked through s2central's wiring diagrams and then i think i just earthed the test line and it then stopped the fault from occuring. When i switch the ignition on it checks everything and then just says ok as if i have already pushed the brake pedal. It's the only way i could sort it.

[johne]

The autocheck relay for the rear lights is inside the rear left hand wing (on a coupe). Following the wiring diagrams on S2central.net you could remove the relay and just bridge the connections at the relay socket so the lights continue to work but no autocheck.

Alternatively you can do the parallel mod to the rear autocheck relay that has been suggested for the front relay and just remove the pin on the relay that sends the alarm signal to the autocheck display.

John

[bad8008]

Same here.
did a VAGcheck. but some errors on the ABS - cleared, but on Airbag not able to clear.
I too have the 3rd brake light.

[bad8008]

The front autocheck light unit checks the two dip beam headlights.

The rear autocheck light unit checks the brake lights and rear tail lights.

No other bulbs are checked so, no the reverse light isn't covered and isn't going to be the cause of your problem but if you have a central brake light, that will upset the system if the central bulb(s) is connected in parallel to one or the other of the side brake lights. You need to make sure the central brake bulb is connected directly to the brake switch before the rear autocheck unit, not after the autocheck unit.

See wiring sheet 34/3 in S2central.net wiring pages.

John

John,
which sheet you refer to? "34/3"?