N_Jay

UPDATE:


Seems I have a new problem.

The power trunk feature does not work at all.
(Latch and Lock work as expected, from trunk handle, from door switch, and from remote)
Will not power open or power close. (No noise from motor at all, no motion at all)
Does the same thing from the handle, remote or drivers door switch.
The power latch cycles, so you can "pop" it and then hand open and hand close.
All rear taillights work fine. (Checked license plat light)

No dash error.

I think the red trunk buttons are not lit (Will check tomorrow). (Red Lights are NOT lit)
Guessing it is either a popped fuse, or maybe a different wire in the trunk bundle.
(Checked wire bundle and checked fuse. Both good)

I fixed the famous broken brown wire a coupe of years ago, and at that time none of the others looked bad, and I rewrapped the bundle to move the stress from that point.
(Fix looks good, unwrapped and no new signs of stress or rubbing)

Also wondering of it was a wire, why the remote or the drivers door switch would not work? (

Maybe a wire frayed and shorted taking out the fuse? (Nope and Nope)

Thoughts anyone? (HELP!)


All New Below
________________________________________

Kind of thinking it has to be the controller, the position sensor, or a secondary trunk open/closed switch.

Does anyone know if the trunk has a second switch that the controller may reed as a safety, or is the position sensor the only one?

Anyone have a controller or a position sensor fail?

Anyone have a diagnostic service sheet on the trunk opening system?

cetialpha5

Check the wire again. I think when mine went it was one ground wire which affected several items, but maybe just the power wire went on yours. Much rarer is the motor going bad which doesn't sound like it if the buttons aren't lit.

N_Jay

Will check the fuse first and wires second.

N_Jay

Bump!

New info in first post. Help wanted!

konigstiger

See attachments for better understanding of system, control module actuates the motor.

N_Jay

Thanks.

Seems the likely candidates are the position sensor (2118201597), the controller (2118204526/2118703026) and /maybe the latch switch.

Anyone have any of these three fail?

N_Jay

Tested the motor with a 12V battery and a ammeter in series. (From the connector at the controller, with the controller unplugged)
Runs both ways nice and quiet, moving the trunk lid as expected.

Tested the positions sensor at the input to the control module (connector unplugged).
Shows about 4.1 K oms across the resistor and the center pins changes resistance with moving the trunk lid.

Tested the motor on the lower latch with a 12V battery and a ammeter in series. (From the connector at the controller, with the controller unplugged)
Latch moves up and down smoothly.

Tested the switch on the lower latch at the input to the control module (connector unplugged).
Latch down (normal/closed state) pins 4 and 5 closed, pin 6 open.
Latch up (Latch motor run up using external battery) Pins 5 and 6 closed, Pin 4 open.

Latch returns to down (normal/closed state) when reconnected to the controller.

Upper latch cycles with all three ways to open trunk. (Trunk handle, Fob, Door switch)
I am not sure what switches are in upper later because that is read by the rear SAM, not the trunk controller.

More notes.

Drivers door switch red light, and trunk pushbuttons red light do not light ever.
Lock/close button locks but does not close.
All other lock/unlock switches work as expected.

Dash provides no warning that trunk is open when running and put in gear.

HELP!!!!!

I think I am down to the controller unless someone has another explanation.

Anyone have a used controller I can use as a test?

N_Jay

Bump for HELP!!!!!!!!!!!!!!!!!

I have replaced the trunk controller and nothing has changed.

It is as if the controller or the car does not know it has a power trunk opener,
or some part of the circuit is not getting power.

I am 99% sure the main 30 A power is working because when I pulled the fuse I had no latch operation.
In the name of thoroughness I will be checking for power at the controller plug.

Is there a rear SAM fuse for the circuit also?

Might pull each rear SAM fuse to double check.


This is starting to drive me just a little crazy!

P.S. I am not in possession of a spare controller should anyone need one.

N_Jay

Next I may reassemble the trunk with the drive gear removed so I am not spinning the motor and wearing the internal clutch with every open and close.

I really hate disabling such a handy feature.

cmriv

What year is your car?
Your rear end closing control unit is wired to both, rear sam and rear pre-fuse.


Have you tried normalizing the rear end door?

cmriv

If that red light isn't lit that may be your issue. That switch may be stuck in one position, causing angle detection sensor to not know whether door is open or closed. Pretty sure that light is suppose to be illuminated when rear door is open...

N_Jay

Car is an 2007 (P2 built in 12/06)
Both the original and replacement controllers are the "updated" model number.

How do you "Normalize" the trunk lid?


Which switch do you think may be stuck?

cmriv

the red light switch. Do you have a lwb or station wagon?

N_Jay

I have a normal US market 2007 E350-4Matic-Sport-P2.

If it was a wagon it would not a trunk lid.

I don't think the US gets the LWB.

N_Jay

Does the rear SAM have a separate fuse for the Trunk or does all the power come from the battery fuse box?

Everything else the rear SAM controls seem to be working fine.

cmriv

Trunk lid control unit gets power from rear fuse box, not the rear sam, but the fuse box next to main battery.

TLC is wired to rear sam for the sole purpose of CAN.

The drive motor gets powered from the control unit itself.

Everything else in rear sam could be working fine however if you are having CAN communication issues with TLC nothing will happen.

N_Jay

Hmmm, Thinking.

The trunk opens from every switch so I know the rear SAM is on the CAN.
I replaced the box, so I doubt its CAN in is bad.
The CAN can't be shorted or other things would not work.
I assume the SAM has a single CAN out so it must be working.


How can I test that the CAN is talking to the Trunk control box?

cmriv

I've just spent the pass 30 minutes looking at function diagrams for the auto closing feature on the 211. Honestly you need some MB diag equipment. There are wayyyyyy to many variables for me to try and walk you through what the issue could be.


If you installed a new control unit yourself it very well could need initial startup performed.

N_Jay

Do you know for a fact that controller need initialization with MB?

The system does the EXACT same thing with the original controller and the replacement.

My last guess is going to try to see if the upper latch actually has a switch that gets read on the CAN.
I know the CAN talks to it since it unlatches properly, but I don't get a "Trunk Open" light or warning.

I am trying to figure out what S88/8 on the diagram (Trunk lid external operation switch) is .

cmriv

S88/8 is the exterior grab handle.



it may still be doing the same thing because there are dtcs stored and I/S hasn't been performed. But again everything i'm stating is speculation as i'm not physically around the vehicle with diag equipment.

N_Jay

OKJ, now I see S88/8 is the grab handle.

It works, as does the green safety button in the trunk.

I am falling back to the car not knowing the trunk is open.

a) The switch in the S88/4 Pawl rotary tumbler (Upper trunk latch)
b)The wire going top the switch in the S88/4 Pawl rotary tumbler (Upper trunk latch)
c) The Rear SAM not reading the switch in the S88/4 Pawl rotary tumbler (Upper trunk latch)

Pulling the latch out now and will check the switch and the wire with an ohmmeter.

Hoping for the wire (Cheapest fix)
Second for the switch (Easy fix)
Last the SAM (There goes the extra $1200 I picked up this week consulting)

N_Jay

Stupid MB!

Took it all apart.

Tried checking voltages and switch contacts, but could not make heads of tails of what I found.

Put all the wires back together and it was completely dead, no trunk latch activity under any circumstances.

Crap, broke it good, I figured.

Put the latch back in and reattached the emergency escape switch. Pushed it once and the alarm went off, and the motor opened the trunk the rest of the way.

Put the latch back in and now it works to close abut dead to open.

Cycled the latch a few times with a screwdriver blade, and it all starts to work.

So, now I have to put the trunk all back together not really knowing what was wrong and when it is going to fail again.

I'll be shopping for a latch assembly, and if anyone needs a control module, I have a deal for you.

cmriv

It works that way sometimes. Start poking around and ya fix the issue with out knowing what it was. You may want to try normalizing the rear end door too if possible.

N_Jay

How do you go about Normalizing it?

cmriv

close trunk lid manually. open trunk lid via button on drivers door until lid has reached upper stop limit. then hold driver trunk lid switch in the "open" position for 4 seconds.