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View Full Version : Mercedes SAM rear fog light: repair solution



electro10
23rd July, 2022, 11:16 PM
Hi all,

I had a situation with a Merecedes Sprinter that rear fog light no works (SAM is identical to image).
The light switch is ok, and with diagnostic machine I tried light up but the result is the same, always off. In SAM, there was an error "rear fog interruption / short circuit".

So, I opened the unit (remove screws and black plastic) and checked the connections:

Connector <-> High-side driver: The light turns on/off by a IC VND5E050ACJ
High-side driver <-> MCU: with a resistor between, the pin 4 is a current signal proportional to current consumed by light.

I measured signals, and IC is damaged!
I hadnīt this IC, and only found now on aliexpress. So, I replaced with a VND5050J. This IC, the output current signal relation to current consumptions is a little different, but works: but unique situation is that sometimes, when turns on rear fog lights, the same blinks a little 4 times.

The image with IC replaced!

I hope that this can help someone in future!

fuzz1
24th July, 2022, 03:26 PM
Hi
I guess you will replace the IC with the one you ordered. Wouldn't mind hearing if the intermittent fault goes away for good.

electro10
24th July, 2022, 07:44 PM
Hi
I guess you will replace the IC with the one you ordered. Wouldn't mind hearing if the intermittent fault goes away for good.

Sure, I will replace. But, for now, was the best solution ;)