Running lights GONE

[jamiller45]

I will try to resend the PDF when I get to the office in the morning.

[peterfinurke]

Thanks John, I have gotten home driving only daylight. Anyway, the Park In voltage is present on the plug 12v, but there is no output on the AMP 1-480700-0 terminal from the board for the Running Lights. I removed the module and don't see any bad solder connections or obvious burnt components. Unless you have other suggestions, it appears something has gone bad on the board.
Suggestions???
Thanks Peter

[jamiller45]

All of the fuses next to the plugs are ok?

[peterfinurke]

Yes, I metered all the fuses & they are good, the grounds are solid, connectors are crimped good.
Following the circuit board from "Park In" it appears that it feeds the trigger power to activate a relay that supplies the 12v battery from the lugs to the output jack "Running Lights"
I suspect the relay is bad.
Peter

[jamiller45]

That very well could be. If you feel confident, maybe remove and replace the relay. I spoke with parts/warranty and they would just recommend replacing the whole controller...how old is your unit? what model is it? I'm just asking those to understand how long this lasted before having a problem, because we haven't had many issues at all with the controller.

[peterfinurke]

My unit is a 2011 Solera purchased new March 6, 2011. All other functions of the controller work. I would prefer to repair the existing controller instead of replacing unless it is a warranty item. I am trained and experienced at bench level repairs on printed circuits. Replacing the relay should only be a few dollars and a few minutes soldering, compared to the expense of replacing the whole controller.
Peter

[jamiller45]

Yeah I was thinking the same thing...but I don't know how experienced people are in doing something like this...and i don't want to tell someone to remove and replace something if they don't have the ability to do so. It sounds like you might be out a few dollars and maybe 15 minutes of your time if the relay isn't the issue. Keep me informed on the outcome please.

[cousin01]

Thanks to this post i located the panel in the utility compartment.

first noticed problem after hooking up small trailer to the trailer connector. I have done this before and all lights worked fine so something has changed.

Using an adapter to connect my 4 pin trailer plug. If not mistaken, pin 3 from the top is the running lights.

No voltage at this pin with headlights on.

Disconnect 3 pin molex connector that is the subject of this thread and I read 12 volts at the pin on the circuit board that corresponds to the brown wire.

Connect the molex to the circuit board and no 12 volts at socket three, of the trailer connector.

Check continuity from female connector in molex connector to pin 3. Check OK
this should eliminate the bad crimp as a possibility. (btw how did you remove the molex pin from the socket in order to solder it? My experience says it requires a special removal tool)


Reconnect molex connector. Turn on headlights, jamb test probe into back of molex socket at brown wire - no 12 volts (12 volts present on the other two molex sockets)

disconnect molex - Check resistance from brown wire in molex connector to chassis ground - looks like dead short!!! (why am I seeing direct short?)

So what is happening? 12 supplied by chassis for the taillights, but when circuit board sees dead short it shuts down the voltage to the running lights rathr than blowing a fuse?

Defective control board in the utility compartment?

Mercedes monitors current draw and it shuts down the voltage to the taillights? I would like to check the voltage for the tailights up front at the mercedes fuse panel(s) but I can't figure out which fuse supplies that line to the utility compartment.

Any ideas?

Schematic for the control board?

[cousin01]

Would you have schematic of the control board and a clearer diagram of the wiring harness?

Here is my problem and T/S steps

[peterfinurke]

I finally repaired the problem with my lighting.
It appears that when I had a blowout on a trailer I was towing the damage to the fender shorted the clearance light. That caused the output relay on the module to fry.
I contacted the manufacturer looking for a schematic, help, etc. American Technology Components out of Elkhart, IN. They offer a repair service or replacement of the module & their support was quick to reply to my request.
Although I did not receive the schematic, by tracing the circuit on the board, it goes from the "park in" pin (gray wire pin 4 at top) through a capacitor & then to the relay. Relatively easy to trace without a schematic.
I was fortunately able to find a replacement relay & replace it on the printed circuit board myself. Good luck & thanks to all who offered suggestions and feedback.
This is a very useful forum.
Peter

[emilizik]

I had the same trouble with my tail and marking lights when I wired in my towed car. I was looking for a blown fuse, I could not found. I took my Solera to MB dealer, they have told me, there is now fuse for the Tail light, it is controlled by a SAM computer. The trouble he found is the lights were over loaded and the SAM shot down the tail and marking lights. He then ran a separate wire to SAM for the tail lights and it has fixed the problem.

[cousin01]

Peter..

Sounds exactly like my problem. I did have a frayed running light wire on the trailer. I t might have shorted out.

I thought about examining the controller board but realized it looks like is fed from the 12 volt chassis battery.

what all did you disconnect before removing the controller board assembly from the utility compartment?

[cousin01]

Originally Posted by emilizik

I had the same trouble with my tail and marking lights when I wired in my towed car. I was looking for a blown fuse, I could not found. I took my Solera to MB dealer, they have told me, there is now fuse for the Tail light, it is controlled by a SAM computer. The trouble he found is the lights were over loaded and the SAM shot down the tail and marking lights. He then ran a separate wire to SAM for the tail lights and it has fixed the problem.

Who or what is SAM?

[peterfinurke]

Removing my controller for inspection & repair:
There were 3 mounting screws board to back wall, top right, & 2 bottom & 1 tie wrap on the wire bundle screwed down. After removing the screws, I had to chip away at the foam in & around the wire entry hole to get some working room.
On the board the battery power goes to the 2 lugs, top left is ground w/4 spade lugs & 1 bottom left 12v+ disconnect & tape the 12v+, it's hot.
Unplug the three molex plugs & you have the board out.
The front & back are screwed on at the corners, but the front aluminum plate has 4 pop rivits attaching plate to 2 of the large capacitors. I drilled the pop rivits out & then inspected the board. There was a slight discoloration at one of the relays but until I put external power on the lugs and into the "park in" the relay was silent. I tested the other, which was left turn & it clicked & I had voltage out on the bottom left 3 pin molex output to Solera lights.
After removing the old & soldering in the new relay, I tested again with power on the lugs & 12v+ to the top molex "Park In" The relay clicked & I got 12v+ out on the running lights out pin bottom left.
You need the wiring diagram that is on this thread to identify the pins and wire colors.
See my post from earlier today, American Technology Components will repair it for you or they sell a replacement board. Nice & helpful to me, you can contact them at www.atccomp.com
Hope this helps. Peter

[jamiller45]

SAM is the Merecedes Benz control module that sends electrical signals to where they need to go. It is located behind fuse block in driver side kick panel.

[emilizik]

The tail lights and the marking lights, I believe it was the brown wire has separately relayed back to the SAM's control mo dual, located in the fuse Box above your left foot. When The Sam detected overload, it shots down. I hope I answered your question.

[mckirby50]

Just bumping this thread back to the top