‘02 ML55 has had an intermittent issue with the engine shutting off. This has been an ongoing problem for years but so infrequent I only addressed the issue two years ago.
I found a badly corroded feed thru connector located on the firewall behind the battery box.
All was well for several months then all the sudden everything came on during a stop at a red light.
Headlights, wipers, horn, flashers and every warning light on the instrument cluster was lit.
I pulled fuses to shut things off. Disconnected the battery to see if it would reset.
Nothing resolved it. I have to leave the battery disconnected to prevent current draw.
Other than this weird problem the truck is in great shape, low miles and new tires.
Any ideas where to start? I am technically incline and have repaired modules before but this is just too weird.

Check for signs of water (damp carpet) at the front footwell, both sides. Also at the fuse box behind the R/F kick panel.

No water ingress.

I have reseated all connections in the fuse box. I also pulled the All activity module and examined it for cold solder joints and oxidation. Nothing abnormal found.
I suspect a goofy AAM.

All but 2 of the 24 relays in the main fuse box are active as soon as the battery is connected. Key not in the ignition.

I reseated all connections in the fuse box. Also removed the all activity module and examined its PCB for broken solder joints.
Nothing abnormal there.

Puzzling.

I’m suspecting a bad AAM.

Can anyone point me to an online wiring diagram for the W163?

Parts guy at the MB dealer says he thinks it’s a failed rear SAM unit.
Lol. I don’t think it even has one. 🤣🤣🤣

No SAM-R on 163's.....

Nope. Idiots

Probing around I discovered I have zero volts on fuse 15 and 16 engine compartment fuse box.
I had hoped to obtain or at least look at a diagram today at the dealer. No such luck.

Three years later…

This ML55 has been sitting all this time due to the AAM being NLA. Part 163 545 71 32 is obsolete they tell me.

I ask the dealer if I could bring one in and have it coded to my vehicle. They said no.

I will either be selling the ML55 as is or parting it out. Low miles and in excellent shape.
I just put new tires on a week before thing went nuts.
No more Mercedes products for me.

I see them on Ebay ? > your part # says thats for a 320 / or a 430 BTW ?

https://www.ebay.com/itm/223500835384 $125

After all this time I have located a good module. Everything seems to be working fine now.
Now to find a buyer.
138k, meticulous maintenance and in very good shape. I just replaced the fuel pump also.
Tires are new but have flat spots due to sitting. They may roll out.
Pricing it accordingly.
$3500
Located in Farmersville Tx north of Dallas.