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Old 06-18-2020, 12:57 PM
Das_Boost Das_Boost is offline
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Join Date: Sep 2019
Location: Columbus, OH
Posts: 31
Quote:
Originally Posted by christuna View Post
Ok good info so let's diagnose it.

Wiring diagram for lights on your car:
http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/24821300.pdf


1. tail light

How the power goes:

N7 -> E4x1 connector -> tail lamp -> E4x1 -> W7 ground

I think we can eliminate a bad ground since all other lights work.

Find connector E4x1 (should be behind the passenger side trunk panel)

Disconnect the connector and find terminal number 6

With a multimeter put one probe to ground and the other probe in terminal 6 check if you're getting voltage.

This way we will narrow down to where the problem is.


2. Front marker light

Because your flasher works then we can say that the ground point W10 is good.

Disconnect the right side turn signal/marker light connector.

With a multimeter put one probe to ground and the other probe in terminal 4 check if you're getting voltage.

Terminal 4 goes straight from the N7 relay.


do these 2 tests and then we can diagnose it further.
Thank you very much for all this information. I started to test everything last night, and after reading some other threads somewhere on the web where people experienced similar issues, a few people mentioned a broken solder connection inside the N7 relay itself. So my curious mind decided to open it up and check. Sure enough one of the solder connections was cracked. I reflowed the solder, and reinstalled, and all the lights worked. I’m positive I got lucky finding that, and I really appreciate the link to the wiring diagram. I’m saving that for future reference.

However I have noticed that if the relay is jiggled or moved, the corner light “connection” comes and goes, and the front right fog light will occasionally do the same. The rear tail light works as it should 100%. So at least the most important light is functioning.

I’m wondering if I should just replace the N7 relay to be safe.
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