Diff switch

[audinut]

I have an annoying niggle thats getting me down.

my little pic of the car on my diff lock switch doesnt light up

i removed the switch the other day and tried to wire in a small dash bulb (12v) but it still doesnt light up

im going to be doing my ex temp display soon as ive seen a guide on here somewhere , can anyone tell me what bulb i need to solder in to make the diff switch illuminate again!

thanks in advance

[mr ed]

page 10 http://www.s2forum.com/forum/showthread.php?t=28798

[CoupeWannabeS2]

Just following on from this thread, I have just changed the two little bulbs in my diff switch and it still doesnt light up (it hasnt since I owned the car).

I can see the two bulbs I removed have broken filaments, and the new ones soldered light up if I put 12v across them.

I'm wondering if I have damaged my circuit board. I made sure the plug was put back on correctly (as per the interior lighting thread linked above). Could too much heat from the soldering iron have caused damage? I still get the word "diff" light up. and the triangle lights when I push the button.

As an alternative, could I just run two wires off of the cigarette lighter bulb to the bulbs in the diff switch?

[CoupeWannabeS2]

Just been checking the diff switch again. Turns out the switch no longer turns the diff-lock on. Doh.

I'm guessing I have damaged the circuit. Has anyone ever successfully replaced the transistor on the circuit, as I assume that is the component I have damaged?

Alternatively has anyone got a spare difflock switch for an ABY?

[UrS4boy]

Just been checking the diff switch again. Turns out the switch no longer turns the diff-lock on. I'm guessing I have damaged the circuit. Has anyone ever successfully replaced the transistor on the circuit, as I assume that is the component I have damaged? Alternatively has anyone got a spare difflock switch for an ABY?

When you say "difflock switch" you meant the entire assembly with the switch, the housing and the printed circuit board, right? These are not specific to the ABY S2, they are the same from 1988 to 1996 (the RS2), including the 100q, the 200 20vt, the 3B S2s, the UrS4 and UrS6 (95 only) and the RS2.

[CoupeWannabeS2]

Yes, the switch, housing, and circuit board is what i am referring to.

The only part I tampered with is the circuit board listed as number 8 in the part list.

I thought there may be different switches so clarified what car I have.

[UrS4boy]

I thought there may be different switches so clarified what car I have.

My point was your source of used complete diff switch units is not restricted to just an ABY S2. You could source one from any of those cars that I listed, i.e. I am helping you, not criticizing you.

[CoupeWannabeS2]

My point was your source of used complete diff switch units is not restricted to just an ABY S2. You could source one from any of those cars that I listed, i.e. I am helping you, not criticizing you.

Sorry fella, didnt mean to offend.

Thanks for the advice.

You wouldn't happen to have a spare switch would you ?

[andy10v]

How to change the bulb here

http://www.s2forum.com/forum/showthread.php?t=28798&highlight=diff&page=10

This may be your issue?

When coming to reassemble your switch after you've replaced which ever blown bulbs, you CAN fit it 180° the other way. If you do this, and reconnect it to your wiring plug in the car, IT WILL blow the small black three legged transistor (I assume it's a transistor) and the circuit will be junk.

[andy10v]

There are two different styles btw

[CoupeWannabeS2]

How to change the bulb here

http://www.s2forum.com/forum/showthread.php?t=28798&highlight=diff&page=10

This may be your issue?

I did avoid fitting the plug the wrong way round - however I did stick 12v across the bulbs whilst they were soldered to the circuit board to check they work.

My thoughts are that I either damaged the transistor with 12v, the heat from the soldering iron, or both!

I should have done some more google research before I messed about. I now know that you need to be careful with transistors to avoid damage.

Also thanks for putting up the pictures of the different diff switches.

[UrS4boy]

There are two different styles btw

The latter one, 893-919-214 according to the ebay photo, does not show up when I ask my friend Kate in the parts department. Any idea what it is from?

Interesting, when I asked Kate to check 1988 for diff lock switches, she asked me before or after VIN no. JN 200100. Apparently there was a change from mechanical diff lock "switch" to electronic at that VIN break. Learn something new every day.

[UrS4boy]

Diff lock switch changes

After being pointed to the B3 80/90/CQ by yodasfro (Austin C), I was able to answer my question: I was looking for 893919214 which does not show up anywhere. The style of the B3 diff lock switch PN changed at some point 92-93. SO apologies to CoupeWannabeS2. There is indeed a difference between early 3B and ABY S2 diff lock switches. (Sorry, , I was too C4-centric)

Andy10v thanks for the heads up. Subsequently, I was able to find this:

[CoupeWannabeS2]

After being pointed to the B3 80/90/CQ by yodasfor (Austin C), I was able to answer my question: I was looking for 893919214 which does not show up anywhere. The style of the B3 diff lock switch PN changed at some point 92-93. SO apologies to CoupeWannabeS2. There is indeed a difference between early 3B and ABY S2 diff lock switches. (Sorry, , I was too C4-centric)

Andy10v thanks for the heads up. Subsequently, I was able to find this:

No worries fella.

My favourite audi difflock switch has to be this one...

[UrS4boy]

Updated Diff Lock Post

Based on the different switches and my "discoverying" that the electronic 893919173diff lock controller only came into being during the 1998 Audi 200 run (After JN 200099), I have updated my previous diff lock post, at least on my home forum. Here is the link with thanks to Andy10v and Yodasfro for pointing out the different B3 diff lock switch.

http://forums.quattroworld.com/s4s6/msgs/170940.phtml