Hey everyone new user to the forums here. Did some searching and tried a few tips on how to fix my problem, but so far nothing has worked. When I hit the lock or unlock button on the fob my lights flash but the doors won't unlock or lock. Took it up to my local Chrysler dealership to see if they can reprogram or resync my fob with my car and told me they couldn't and referred me to another dealership that could. Talked to the other dealership and the service department told me that no one can program the fob and that they come from Texas already programmed... they won't even take a look at my car. Kind of stuck on what to do, any help would be appreciated.

 

THe car is old enough that dealers are done with them - remember, you are driving a Mercedes SLK320 with a different body and altered electronics.
Chrysler dealers dont' want anything to do with your car, and the guys in the service department hate the car 'cause it makes them look stupid when they are not stupid.

Ok, if the lights flash, the FOB is fine. This is a pump issue - the locks are pneumatic, that is, a pump in the trunk operates them.
If your car is a Coupe, lift up the mat in the trunk and find the pump (it has a bunch of yellow hoses going to it). Did it, somehow, get wet?
Because wet pumps are a major cause for this kind of complaint. YOu can also start checking fuses in the big box under the hood on the driver's side, but I'd look at the condition of the pump first.


NOW, to PROVE what I've said, get in the car and start it. Use the button on the dash to lock and unlock the doors - if it doesn't work, look at the pump and fuses.
If it DOES work and your FOB doesn't - Im lost. That would make little sense, since the controller is flashing the lights THINKING the doors are being locked and unlocked.

 

Check to see if you can hear the pump working, listen in the trunk with the mat out and press the button, you might hear it, if you hear a hiss then a hose has probably broken and needs replacing.
To get to the pump you have to remove the mat and the foam block on the right. To remove the foam block you have to take out the two left and two right panels and the rear panel. Before doing that see if you can see water down behind the foam block. If you find water you have found your problem.

So first listen for a noise when the button is pressed, does the trunk and gas cap lock?

 

I wondered how hard it was to get to in a coupe...

 

The button on the dash doesn't lock or unlock the doors, and I can't hear the pump. Sorry for the late replies I took the car to a friends to see if he could have better luck with it. Tomorrow I will test the fuses and take a look at the pump itself. Thanks a lot for the advice!

 

Also the trunk is locked so I will have to deal with getting it opened first lol

 

Hi bwright396

I have the exact same problem that you had. I was just wondering how you ended up solving the issue with the locks and fobs not working.. Was it water in the trunk and pump or module issue?

My trunk is also locked so I'm guessing it may be difficut to get unlocked manually.. How did you get it unlocked in order to get into the bottom of the trunk..

Any insight would be greatly appreciated right now..

Thanks in advance.

 

The lower trim panel on the inside of the hatch is removed by unsnapping it around the outside edges after removing the hidden screw at the bottom of the closing hand grip pocket. Remove the cover of the screw with a small screwdriver or something similar.
I have forgotten what the insides look like but all the air and vacuum lines go to the upper lock half here. If you cannot unlock the latch here maybe you can see if there is a broken hose here. I guess it is possible to add air pressure or a vacuum to the proper line and activate the latch if it still works. The three remaining panels pop of as well and maybe there is a broken hose to be seen at the top of the hatch.
I am not sure if this can be done with the hatch closed though and my car is not handy for me to check.

 

Thanks for the detailed step by step 180.

I just came back from my shop where my car is stored only to discover after a day of just letting it sit there everything had unlocked itself... I also noticed that the tow switch had stopped blinking etc.. So when I opened the doors now no alarm going off.. Good thing..It definitely is possessed lol I lifted the hatch and pulled fuse 9 to get the lights off so it doesn't drain the battery.

I noticed that the boot at the top passenger side was already disconnected which probably means that somebody prior to me had already fumbled around there to check for a broken line or something... Also perhaps having the boot disconnected there it anabled water to get in and get water down into the well.. I will certainly not close my hatch now til I remove the floor to checkout the pump and module...

I still can't unlock the doors though with the fob and consol switch..

If my fob is out of sync would it still flash the lights when I press the lock and unlock buttons on the fob?

Thanks

 

If you pull fuse #9 the remote lock/unlock will NOT work.
Along with supplying voltage for the dome and cargo light, it supplies voltage to the BCM for powering the link between it and the locking pump.

 

Forget the fob for now, but I think it works properly. The problem is in the security/pump module. The relays seemingly work when they click but may not let power through if the contacts burnt. I would expect the power goes through them to the security module and it appears to be the problem.
The broken rubber boot will definitely let water into the trunk and it ends up in the wells and will ruin the module. I suggested the module as the problem in post #2.

 

Thanks Ala. Fobs don't work with the fuse in. I just took the fuse out in order to keep the hatch open.

I tend to agree with you 180.
Also being winter here there is no better time to open the trunk up and look inside for problems and fix it now. Also wouldn't hurt to take out the Rcm and have a look at that for potential future issues.

I guess I could test the relays too. Should I test both the yellow and black one or just the yellow?

Also is there a section in the service manual that explains how to take apart the trunk trim panels and foam to get to the pump?

Thanks guys. Have yourselves a great weekend.

 

Update.
I removed the foam etc in the trunk to find the locking module. Everything looked pristine down there. Wires look nice connections are clean.
Took apart the module and everything in there looks brand spanking new...
There was a little dust right down at the bottom of the lower plug. A little rust around the plug but nothing serious... Not sure what the hell to do now... Also does anyone have a part number for those little white clips that go into the interior trim panels? A few broke while removing the upper plastic trim mouldings.. Any help here would be a life saver..
Thanks

 

I have to say that I am sorry to hear that, if you know what I mean.
When you push the dash button or the fob buttons do you hear the module work?

 

Yup I was hoping to find something down there and fix it and be done with it.. No such luck...

And no I didn't hear anything back there when I press the consol button to lock and unlock.. I never tried it after removing the floor though but I'm sure I would have heard something even withy the floor on.. Correct..

Do you think that it could be the Rcm or the black or yellow relay?

Any thought would be great. Thanks

 

There is also another little module of some sort bolted to the lower side wall in the trunk. Small plastic box. It looks good but who knows really.. Does anyone know what this little unit is?

 

It is the anti towing module. When the car is lifted one end it starts the alarm.
I would try to see if the locks worked just using the button on the dash. This would let us see if the hard wiring worked or not.
I Would like to see a list of the symptoms as they are now, the symptoms have been spread through four different threads and it is too hard to read them.

 

I just purchased this car in December and everything was working correctly.
I've never even taken it on the road yet.
Trailers it home as it is winter here.
Had it in the shop. Was told by the previous owner that the battery needed changing. Old battery went dead so I bought a new one.
Installed the new one and when I finished the battery connection the lights started flashing. No noise of the alarm. The alarm could not be stopped with fob, key etc.. Fob would only flash lights and not open doors.
Tow switch flashed and could not be stopped by pressing he button.
Car started just fine even witht the flashing lights etc..
Changed the fob batteries.
The car seemed to unlock itself though after manually locking the door ps with the key. The next day I would find the car either locking itself or unlocking itself..
Only to find it one day unlocked and tow switch being off for whatever reason..
Fob still flashed lights but do not unlock or lock anything. Consol button still didn't work.

I will have to try it again and see if there is any changes... Reconnect the battery and go through the motions of trying to lock and unlock.. I don't want to shut the hatch though just in case it decides to lock itself again..
Does hatch have to be closed in order to lock and unlock with fob or consol button?

All fuses by the battery are good and also the ones on the driver side under the hood..

 

What would happen if I unplug the tow module ? Also I took out the batteries in one of my fobs forth entire night to see if it would loose its sync and react differently then the other one. But when I put the batteries back the next day it still flashed the car lights and looked like it didn't affect the sync.. Is this possible? If the fob would loose its sync would it not have any affect on the car.. No flashing lights and nothing.

Oh and I changed the alarm module as the internal battery wasn't any good any more

 

What happens when you use the key to open and close the locks on the car?