gaineserau

A MB world member Euler was kind enough to give me some info in this great post about the W164 locking system.

https://mbworld.org/forums/m-class-w...k-problem.html

However, I never have found the REAR door lock module. My front SAM is sending the correct signal to unlock my left rear door, but the door lock never receives it (yes, its a BRAND NEW lock actuator--that's not the problem). Further more the door LOCKS PERFECTLY!!! According to the schematic, and my own observation, it appears the wires that power the lock reverse polarity to lock/unlock.... Also According to his schematic for the right side, there is a model between the SAM and the door. However, there is no module I've found INSIDE the left rear door.

Does anybody know if there actually is a REAR door control module? Or are the rear doors controlled by their respective front door control modules? The schematic in the other post seems NOT to support the idea that the front DCM has any output to the rear doors, but I have not found for sale anywhere on the internet, a REAR DCM....

Thanks

Plutoe

Post your VIN!!

gaineserau

Sorry for my very late reply. Vin is 4JGBB25E89A487843.

Thank you

Plutoe

Not a problem----you do not have a R and L rear door control module---you have a R and L central locking motor and the rear SAM based upon instructions from central gateway actuates the R and L doors.


The central locking system is very complicated as you are learning!!

gaineserau

Thanks Plutoe!! Yes it appears the SAM is sending the lock/unlock signal to the motors. I can watch it on my star clone scanner. Aren't the lock and unlock wires the same? In other words, don't they just reverse polarity to make the opposite happen? If yes, then I'm completely dumbfounded on what this could be.

Many thanks for your input
Jason

Siksnot

I have the same problem, same door. also replaced the lock actuator with no fix.
Locks but does NOT unlock. SAM is sending the signal according to icarsoft i980.
Did you find a solution to this problem?
Is there two control wires with common ground or is it two wires that reverse polarity from SAM?

Maj. Dundee

It could be a few things that cause this problem; door lock actuator, severed wire or front SAM module.

The easiest thing to do is access the front SAM under the R/F seat by removing the three plastic covers.

Find wires #21 WHITE & #22 VIOLET/BLACK in connector "F". These two wires are responsible for locking and unlocking the left rear door. Strip a thin wire at both ends. Pull up the door button.

Place one end of the wire on the POS. battery terminal and with the other end momentarily touch the WHITE wire pin and see if the door locks. If not, do the same to the VIO/BLK wire.

Don't reinstall the battery covers as you might have to access the SAM again. Place a heavy towel over the battery area so nothing can fall in.

Post back with results.

Siksnot

Thanks Dundee, I will give this a try.

gaineserau

Dundee thank you so much for your info. I am the author of the original thread and still have never solved this problem. I had my car into the dealer for an alignment and they claimed again, the door lock was bad after testing. I ordered ANOTHER new door lock and installed. Problem still here!

door locks fine! Door does NOT unlock.

I tried your your wire test today on the front SAM. With the battery connected to the vehicle, I connected both the white #21 wire and the violet #22 wire from connector F in your diagram, each tapped to positive terminal. I saw no movement up or down on the door lock and heard nothing.

Any other ideas? Like scot, it at least appears in my STAR clone scanner that the signal is being sent from the front SAM to the rear door locks. I'm perplexed...

Maj. Dundee

Ok, remove key from ign. Then remove conn. "F" from the SAM.

Then locate conn. "E" (leave in place). Locate wire E2 Brown (Ground), then locate wire E1 Red (12v).

With two thin wires stripped at both ends, insert the end of one wire to pin 21 White at conn. F and the other wire to pin 22 Vio/Blk and tape both wires so they do not move.

Pull the door button up and with the other ends of the two wires, hold one wire to pin 2 conn. "E" and with the end of the other wire, momentarily touch pin 1 and see if the door locks.

If it doesn't, reverse the procedure with the two wires at conn. "E" for reverse polarity.

Do you understand everything?

gaineserau

Dundee again, thank you so much for this extremely valuable insight!

Good news!!!

when I did your last test on the F #21 and #22 wires, the door both locked AND UNLOCKED when I reversed the wire polarity on the E connector power wires. So the continuity must be fine to the door motor right?

Would this mean i need a new front SAM? And if that is the case, is it a simple plug and play with a new one or does it require special STAR programming?

Or something else?

Much thanks to you,

jason

Maj. Dundee

Just one other thing. Check wires 1 and 2 at conn. E before proceeding.

Another thing, you last reported that my original procedure did not work. Why do you now say it worked?

gaineserau

Dundee,

I tried your procedure from post 7 hooking 1 wire from the positive on the battery to both F #21 and #22. This did not work. Perhaps in retrospect, it was because I only hooked up 1 wire at a time to each F21 and F22 instead of the way you wrote it in post 10.

I tried your peocedure from post 10 and this did work. I checked the E connector and it seems to be firmly in place.

Obviously the door is locking and unlocking properly when the wires are powered in forward and reverse current.

Suggestions? SAM is shot or something else?

Thanks again

jason

Maj. Dundee

I would say so that the SAM is defective. The weird thing about this door lock system is that the three other doors are controlled by the rear SAM and only the left rear door is controlled by the front SAM. Why is a mystery..

Getting a used one would be best, it would be a plug and play. A new one would require programming.

gaineserau

Thanks again and I hope you won't mind if I bother you one last time. That definitely is weird about the locks being split like that!

however, I was under the impression that was the front SAM next to the battery that I've been fooling with. Is it not the defective one then? Im familiar with the rear SAM--to find one used and preprogrammed for me would be difficult because I have the lighting package on my ML and thus have LED tails. I also have the factory row package and I know it also drives that. I believe most rear SAM's that are used wouldn't be programmed with these functions would they?

just making sure--thanks again.

Jason

Maj. Dundee

I inverted the wording when typing which I have corrected, my mistake. The left rear door is controlled by the front SAM and the other three doors are controlled by the rear SAM.

Then you are forced to buy new, but dealers overcharge everyone with removable and installation & programming. Try to find someone with a Mercedes C4 scan to extract the M/B code/s.

Good luck and post back with results.

gaineserau

Thanks for all of your time on this Dundee.

i suppose that is good news because it looks like to me there is not nearly as much optional equipment run by the front SAM. From what I see, heated seats would be about it. I see exterior lighting on here but I'm not sure if that includes my "curve illuminating" foglamp feature. The xenon lights have there own separate module it seems.

Think i I could find another used SAM from a car with heated seats and swap it out with complete functionality? I cringe at what the dealer might charge for a new one and programming...alternatively I suppose if I got another SAM and it didn't function completely, I could take to a dealer and have it programmed?

does this all sound feasible? Many thanks again. Wish I new someone in north Atlanta with a C4 scanner

cheers,
jason

Maj. Dundee

What's the part # on the front SAM?

gaineserau

Part number is 1645406501. It looks like after some online research, the current superseded part number is 1649004101.... I'm sure that's the one MB would have if I called the dealer.

I saw a used one from a 2008 R-Class on eBay that has the matching part but I suppose there's no way to tell if it had heated seats... That was a pretty common option though it seems. Not sure about the lighting deal either.

J

Maj. Dundee

According to EPC, your number was the replacement for the one above. The ones below your # are not applicable because they are in a different vin range.

gaineserau

Got it!

I suppose then I'll find a used one (like the one from the 2008 R-Class I mentioned) with the exact part number, try a swap and hope that all of the stuff in my car functions.... If not, I'll have to take it to MB for programming.

I see you are in the White Plains area? I am a pilot for NetJets and am in the HPN airport all of the time. I owe you a beer if I get a decent overnight there sometime soon!

Thanks again for all of your help on this.

Maj. Dundee

When you get the used one, remove the neg. battery cable and then remove all the connectors. Then install the used one but don't bolt it down.

Then re-attach the neg. cable and check things out. I really wish you luck. Let me know how things work out.

Didn't know what HPN airport meant so I looked it up and it's the designation code for West. Airport.

Daniel Alves

Hi All,

Gaineserau, did you solve your problem replacing the front sam ?

I have the same problem on my R-class : rear left door not unlocking.
I replaced the lock actuator with no fix, then I tested wires #21 WHITE & #22 VIOLET/BLACK in connector "F", as described, working fine.

I bought a used SAM with the exact same part number A 164 540 65 01 and replaced it : now it unlocks fine but I have to lock the door manually from inside pushing down the door latch.
I taked the car to the MB dealer for programming the sam but no change... nobody here in France seems to be able to solve my problem.

Any other idea ? please

Maj. Dundee

You are on the wrong forum.

https://mbworld.org/forums/r-class-w251-70/

Daniel Alves

Hi Maj. Dundee,

The SAM system / locking system is the same on w251 and w164. But OK I will post a new thread.

Thanks