S210 electrical niggle

[W210Virgin]

Could anyone help me please by posting an electrical wiring dia for the tailgate of a S210, 2002 model? The info I need is for the rear fog and reversing lights. Before yesterday I was getting an occasional 'lamp failure' message on the dash but nothing was wrong that I could see. Stripped off the inner cover/ liner thingy yesterday (what a faff that was to get at a few bulbs) and saw that the electrical connections are in poor condition from corrosion. Now I've no rear fog or reversing lamps and need to go back in again to strip and clean it all down. (Don't know why I put the inner cover on again ). The wiring diagram will give me a bit of back up as to what's what. Given that they're all not working (and the rear reversing sensors are going a bit daft) I think I'm losing ground connection. The 3 terminal plug is corroded a bit green internally and this is the main issue along with a bit of surface corrosion on the actual bulb connections on the lights. Poor Merc design. (I wonder did the rear window washer tube leak in there at some stage. Looks very vulnerable to frost...). Also going to take the opportunity and add a fog bulb to the n/s as it's ready for it apart from the wire connection that I can easily take from the o/s. Any suggestions as to a good electrical contact cleaner to those parts that are inaccessible to emery paper?

 

[Will]

You don't want two rear fog lights, only one. They are designed in this way for a reason (so that cars behind don't mistake them for brake lights )

 

[W210Virgin]

Thanks. Interesting point but I think they're done that way to save manufacturers a few pennies on every car sold....

Mistaking a bright pair of fog lights, permanently on, for brake lights....dunno. Anyway, don't want to open a can of worms on this as the lack of any rear fog light is my immediate issue!

 

[mr tibbs]

I would think that if you have a covering of verdigree on the lamp holders that you could be right in your assumption that the rear wiper hose has split at some time. I would try to get emery cloth in there to remove it, failing that Halfrauds sell this Halfords | Halfords Electrical Contact Cleaner 400ml
Hope this helps

Keith
http://www.halfords.com/webapp/wcs/..._productId_195717_langId_-1_categoryId_255223

 

[W210Virgin]

Thanks Keith. Sounds like that should do the trick and will be needed. The lamp holders are verdigree'd and the main connector plug is also internally.

 

[Dec]

I have 2 rear fog lights, factory fitted, if you are supposed to have only one rear fog light then you may upset the bulb out monitoring system by adding another fog light.

Have a second look at the wattage of your bulbs, if the wattage is wrong then it might trigger the bulb out warning. Attached picture is for a W202 so might be a similar set-up to yours.

Note that the bulb wattage for each bulb is visible on the grey plastic moulding beside each bulb.

Dec

 

[W210Virgin]

Thanks Dec. Similar setup yes, but as it's an estate, only the reverse and fogs are accommodated on the tail gate. Earlier cars may have 2 fogs and as part of a penny pinching exercise most manufacturers have reverted to only one now. No big deal really; I just think it looks daft and it smacks of being cheap.

I think the bulb warning will be OK as I think it only registers current flowing. However I can test that before committing. Otherwise the trailer electrics that have been added to my car (by an amateur using those crappy blue IDC connectors) would have caused lots of problems to previous users.

 

[W210Virgin]

Solved

Got it all resolved yesterday evening. In summary the issue was poor bulb connection to the metal back plates on the fitting assembly, both left and right and the male 'pins' that fit into the socket connector were sufficiently corroded such that when I disturbed it all by moving it on day one, it wouldn't re-establish an electrical connection on that exact same tiny corrosion free spot. After a bit of cleaning and scraping down I got it all working again. Very poor quality and more like the type of issue you'd find in a Renault..... Tut tut Mr MB.

I'll be replacing the o/s one though as the outer lens cover was not attached properly. It may have had a shunt at some stage that broke the seal. I've plastic glued it for now but I'll be on the look out for a replacement.

What I will be doing though is making a tiny access hole in the rear inner lining on the tail gate to access the single 8mm nut required to remove the light. To have to strip all that cover off for a bulb change is nothing short of crazy. It's a captive nut too and doesn't even need to be removed. I'll locate it and drill and 10 or 12mm hole and Velcro a little patch on it when I'm done. Something tells me these lights will be off a few more times yet...