'90 300D - No power to ONE parking light

[sjh]

Greetings,

My right (passenger) rear parking light has stopped working. There is no apparent cause. All other lights work. There is no power at the fixture.

I can run power from the other side to make the light work but the burned-out light warning is constantly illuminated if I do that. Fuses are all good.

Any advice? Thanks.

The Good Doctor!

[Aquaticedge]

Trace your wires back, look for kinks cuts or other types of shorts, if there's a ground for that side take a look at it as well.

[compress ignite]

Yes there is one.(Mercedes favorite color for Grounds BROWN)

Did I not tout the benefits of:
http://w124-zone.com/downloads/MB%20CD/W124/Index/Groups/24ElectTrbleShting.htm

at:

http://w124-zone.com/downloads/MB%20CD/W124/Main.html

Model W124 Ground Locations:
http://w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/ground_locations.pdf#page=2

[Billybob]

OP "All other lights work." The other lights would not work if there was no ground on that side!

The first thing to do is unplug the connector at the bulb holder and break out the 12 V test light and verify that the wiring loom is either delivering +12 V or not. It it is, the problem is the wiring in the bulb holder, if not you'll need to start tracing and testing that wire back to it's source. A 12 V test light with a very sharp point that you can use to pierce the wire's insulation is the best way to do that.

[Jeremy5848]

In the W124, all the exterior lights run through N7, the "Exterior Lamp Failure Monitoring Unit." Each lamp is connected separately to N7, which is located in the relay/fuse box. In my '87 300D Turbo (W124, OM603), N7 is a long black rectangular module with 34 pins in three groups and occupies the left-most row in the relay section, that is, closest to the left front fender. Your '90 model should use the same unit (I think).

N7 plugs into three separate connectors in the relay box: one with 8 pins, one with 10 pins, and one with 16 pins. The right tail/parking lamp is connected to pin #10 of the 10-pin socket with a gray/red wire.

Although it is unlikely that N7 has failed, it is not impossible. By removing N7 from its sockets, you can get at the individual pins in the sockets. Apply +12 volts to the pin described above and the right tail/parking lamp should illuminate. If it does not, there is a wiring or ground fault. Check the wire to the pin in the relay box (but it will be difficult to trace through the cables in the car). The right tail/parking lamp is grounded at W7, in the right rear corner of the trunk, behind the trunk lining panel. If the lamp lights, the problem may be in N7. The only practical way to check is to plug in a spare.

Jeremy

[sjh]

Originally Posted by Jeremy5848

In the W124, all the exterior lights run through N7, the "Exterior Lamp Failure Monitoring Unit." Each lamp is connected separately to N7, which is located in the relay/fuse box. In my '87 300D Turbo (W124, OM603), N7 is a long black rectangular module with 34 pins in three groups and occupies the left-most row in the relay section, that is, closest to the left front fender. Your '90 model should use the same unit (I think).

N7 plugs into three separate connectors in the relay box: one with 8 pins, one with 10 pins, and one with 16 pins. The right tail/parking lamp is connected to pin #10 of the 10-pin socket with a gray/red wire.

Although it is unlikely that N7 has failed, it is not impossible. By removing N7 from its sockets, you can get at the individual pins in the sockets. Apply +12 volts to the pin described above and the right tail/parking lamp should illuminate. If it does not, there is a wiring or ground fault. Check the wire to the pin in the relay box (but it will be difficult to trace through the cables in the car). The right tail/parking lamp is grounded at W7, in the right rear corner of the trunk, behind the trunk lining panel. If the lamp lights, the problem may be in N7. The only practical way to check is to plug in a spare.

Jeremy

Thanks Jeremy. I'll look today. TGD

[sjh]

I went to the relay Jeremy talked about and that was the problem. A used one from eBay is on the way. Thanks for the help.

TGD

[SD300]

i had fun in my 190e, the left parking cluster has a small side corner bulb which hooks up to the majority of the R clusters.
When i pulled the small bulb of the left marker it somehow the metal + ve touched the ground, it shorted all my R cluster I "F" around for 2 hrs trying to figure out why my R fuse keep burning out!

It got to be Fuhrer's revenge!

it was a good idea to criss cross the wire by design, but for us without a clear head sometimes u pulled all the hair out balder than Kojak.

With the bulb out lamp on in the panel , driving at night became a real PITA.

[SD300]

sometimes by unplugging the plug u may solve the issue the pins got oxidized , I one time unplug my head lamp plug and id did cleaned out the pins, so now my right head lamp is as bright as usual.
It was dimming while idling , throttle gets brighter.

Someday ve can write a memoirs on funs of owning a Panzerwagen jointly.

[sjh]

Originally Posted by SD300

sometimes by unplugging the plug u may solve the issue the pins got oxidized , I one time unplug my head lamp plug and id did cleaned out the pins, so now my right head lamp is as bright as usual.
It was dimming while idling , throttle gets brighter.

Someday ve can write a memoirs on funs of owning a Panzerwagen jointly.

I pulled the relay and checked the contacts, put it back and no improvement.

I pulled the relay, pulled the plastic cover off of the relay and put the relay back without the cover. It now worked. I put the cover on it stopped working. I pulled the cover off it worked again.

I leave the relay in place, without the cover, everything now works, and then I put the top of the plastic back over the relays and fuses. The relay stops working. I take my hand and I hit the black plastic case holding the relays & fuses. The unit now works.

I ordered one from eBay for $18.

[SD300]

i suppose the cover did some compression or whatever to it so it wont serve her purpose.