Any Ideas? R170 SLK reverse lights not working & drivers door switch also dead???

[Upex]

Hi All,

The wifes slk (1998 auto 230 right hand drive) has no reverse lights (been like that since we bought it - which was funny as had an MOT the same day) and I need to get them sorted.

Firstly checked the bulbs and fuse, all OK.

I then pulled the shift unit and stripped down to the selector mech (electronic bit that has the metalic contacts for the reverse feed) and cleaned that up. Looks to be making good contact etc, but didn't help fix the issue.

Not sure where to go from here, and wonder if you kind folks can offer any ideas from your own experience please?

I think that it could be either a duff wire somewhere, faultly connection, or something more sinister.

I'm leaning towards a broken/lose wire somewhere, as the drivers door switch also doesn't function properly (doesn't activate the internal light or tell the car it's been opened etc - which I really need to sort, as you can unlock the car, open drivers door, put keys in car, close the door and it relocks itself, thinking you've not opened the door at all). I've swapped the door switches round (passenger one works fine) and this didn't help, other than confirming both switches are OK (drivers one worked on passenger side).

I've been trying to find out where the door switch wires are to check them, and wonder if the reverse wires are in the same location? If anyone can tell me the route of the door and reverse wires, that would be great, as I need to fix the door switch to.

Also, I wondered if it's possible to 'bridge' wires from the gear lever to rule our the selector contacts part? i.e. unplug it and 'jump' two wires together to see if it then lights up the reverse lights? If this is possible (to troubleshoot, not as permanent solution) how do I do it? i.e. which color wires do I need to connect to each other?

Sorry for the babble, but hopefully proivides the info needed to start working toward a fix?

Many thanks in advance,

Upex

 

[Upex]

197 views and not one person has anything to say? Wow, normally such good responses from this board.

Anyone know where these wires run or how to jump them from at the switch gear plug?

 

[Upex]

Ok, so no one has ideas etc. So can anyone supply or direct me to a wiring diagrams so I can figure out which wires can be jumped to test the switch and wiring of the reverse switch in the gear shifter please?

 

[Upex]

Bump?

 

[74merc]

I had the same problem on a 202 and although the contacts looked ok in the box you refer to, replacing it solved the problem.

 

[markmifsud]

I am pretty sure I have seen this related to power failure at the reverse switch.

 

[Upex]

Thanks for replies Markmifsud and 74merc.

I've given up on this as didn't know where to start etc and didn't get a prompt that you both replied, so my apologies for no response back then.

Either way, I now need to revisit in the run up to mot time, so 74merc, do you mean the gear selector thing in the shifter unit? If you had not replacing that I think it a good way to go.

However I'd be keen to 'test' the system somehow, i.e. can I jump the wires and see the bulbs light, thus confirming this as the issue and ruling out other bits - does anyone have any ideas how I can do this? As I tried jumping the two wires that come out of the rear left of the shifter unit, but nothing.

Markmifsud - don't know what / where the reverse switch is, or how to diagnose a power failure at it, can you offer any guidance please?

Cheers all,

Upex

 

[Upex]

update

Well, finally got round to looking at reverse lights.

They weren't working due to the rear light metal circuits burning/pitting problem that was part of various recalls. The rear brakes were very bad, and a po had soldered jumpers to the brake bulbs to bypass the knackard metal contact areas.

I hadn't seen this before, so took out the lights and cleaned up the contact patches for all bulbs with a dremal and really cut back the brake ones and stuck some solder back in them to replace the metal that was gone.

All back together, lights work and the reverse lights are back. The bulb out error is also gone for the first time since I've had the car, result!

If you have the reverse light issues, I'd be checking this out first, as it's easier than pulling all the lever gubbings out of the gear selector.

Also for those with bulb out warnings to, there some great stuff here in both these topics, but here maybe a another, as I couldn't find mine. Just got trouble shooting - my bulb out error was in before any lights or brake were pressed. Nothing 'triggered' it, it was permanent.

So just the door switch left to resolve now - anyone any ideas? Read tons, but all point to pse wires and usually have other issues with them, mine is purely the switch best I can tell, but don't know what to check next or where the wires are etc?

 

[trapperjohn]

Cant help much with the switch. 'Appen swop it with the pax door one and check how that effects things, but I guess you have done that already.

 

[Upex]

Hi John,

Tried that and no change, but confirmed drivers switch is ok, as both switches work fine on passenger side, and neither work on drivers side.

I wouldn't b bothered, but if you unlock car and put keys in, it relocks with them inside as thinks you've unlocked and not opened the door.