Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-02-2004, 11:34 PM
Registered User
 
Join Date: Jul 2002
Location: Soggy Seattle
Posts: 30
Unhappy Central Locking Dead 300TE

Help! My central locking appears to have died. After not driving the car for a few weeks I unlocked the passenger side door using the key. Then a few minutes later I unlocked the driver's side door and none of the other doors unlocked. If I unlock them by hand, locking the drivers side door doesn't lock them either.

I've driven it around a little and tried moving each of the locks. I don't hear the motor sound I heard in the past when I locked and unlocked the driver's door. When I lock and unlock the doors by hand I see the other locks move so I'm assuming the vacuum system is not completely shot. I don't think the fuse is blown because the rear lights interior lights and antenna work and I think they're on the same circuit.

So a few questions. I assume there is a switch in the driver's door and I'm wondering if it may have failed. Is the system suppose to unlock all the doors when the tailgate is unlocked? My tailgate lock has always been difficult to open using the key. Locking and unlocking the tailgate now doesn't affect the other locks.

Assuming it's not the switch I gather the next step is the pump. Where is the pump on the wagon? Is there an easy way to test it?

Anything else I should check?

Thanks,
BoB

__________________
1988 300TE
1991 Miata
Reply With Quote
  #2  
Old 02-02-2004, 11:48 PM
pesuazo's Avatar
Registered User
 
Join Date: Oct 2002
Location: Near Raleigh, NC
Posts: 580
Do a search for my post titled:
"Help me find this positive voltage distribution point"
This may be your problem.
__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified
Reply With Quote
  #3  
Old 02-03-2004, 12:08 AM
Registered User
 
Join Date: Jul 2002
Location: Soggy Seattle
Posts: 30
That's very interesting. Might explain some other electrical gremlins I'm having. I wonder if the wiring runs in the same spot in the wagon. If I can find the pump I'll see if it has power.

Thanks pesuazo.

BoB
__________________
1988 300TE
1991 Miata
Reply With Quote
  #4  
Old 02-03-2004, 03:21 AM
Registered User
 
Join Date: Feb 2002
Location: Belgium,Europ
Posts: 196
Bob,

Not so long ago there was a thread on this about "battery drain".
I see you have a W124 T as I am (mine is a 300TD turbo).
These aging wagons are in particular vulnerable in the wire harness going from the clamp (socket) at the inside of the left hinge of the rear door. There are 24 screws on it interconnecting 12 wires. They get tired over the years by flexing thousands and thousands of times. So sooner or later some of these wires get broken and/or damaged insulation.
Some of these wires are "hot" because fed by fuse C : the central locking system and the rear interior lights. So trouble there could cause a lot of different problems : power drain, short circuits, failure of rear wiper, not functioning of rear washing fluid (pump is fed through wiper motor), central locking system, closing assistant failure, rear interior lighting, warning light
"lamp failure" on (with two new bulbs in the licence plate lighting)...and a lot more !
BTW do a search on W124 central locking system. There is somewere a very good explanation with pictures and diagnose. The vacuum pump you'll find it under the upholstery of the right rear seat in a big rectangular soft foam box. Try a search for the power drain too.
Good luck and keep us informed,

Danny
Reply With Quote
  #5  
Old 02-03-2004, 03:40 PM
Registered User
 
Join Date: Jul 2002
Location: Soggy Seattle
Posts: 30
Thanks for your comments Danny. I'm not having any battery drain problems (yet) but I do have a problem with lamp warning light always being on even though all the bulbs have been checked. I'll have to investigate further. If you get a chance I'd appreciate more details on where the "24 screws on it interconnecting 12 wires" are located. Is it in the tailgate or in the body?

I don't think the switch in the door is the problem since I just trigger the alarm system and according the the wiring diagram it uses the same switch.

Looks like the pump is actually under the "floor" under the right rear seat bottom in the wagons. Shouldn't be too hard to get to since the seat bottoms are easily removed. And since it require removing the carpeting I might be able to get at that power distribution point under the floor.

Any more comments welcome. I'll let you all know where this leads.

BoB
__________________
1988 300TE
1991 Miata
Reply With Quote
  #6  
Old 02-04-2004, 02:35 AM
Registered User
 
Join Date: Feb 2002
Location: Belgium,Europ
Posts: 196
Bob,

Fortunately, that socket with 24 screws is rather easy accessible.
You'll find it when you take of the larg black plastic upholstery at the inside rear of the roof (it's fixed with some screws so not difficult). Also, you'll have to loose up a bit the ceiling. When there, you'll see how.
Than, on the inside of the left hinge - it will be at your right hand seated with your back to the front of the car - and close to the damper, you'll see the socket. It's rather big, black and banana-shaped and looks in fact very "old fashion" with his screws. But in reality it's very practical to work on.
Than, still being seaten in the back, take of the black plastic upholstery of the upside interior of the rear door (will be close to you as the opened hatch is upside-down!) fixed with some screws too.
Loosening the 12 screws connecting the rear door cable harness to the socket (mark the wires if that makes you feel more confident) will allow you to pull back the cable. As we can expect the damage in the area where the harness (rather stiff with his 12 wires!) has to flex all the time, check that out first. Don't allways expect to see some damage. Check wire after wire by feeling the insulation.
You will be surprised how easy a broken wire can be felt through the insulation.
I don't use splices to repair : I don't like them and they will make the harness
even more stiffer and thikker, exactly what we don't need. In fact the hardest part of this repair is putting the cable back through that rubber "harmonium" and fiddling it back in his place close to the LH hinge. I am not telling you a secret if I tell you I putt some vaseline to the wire harness?
I cut out the broken part and solder a new piece of wire (of the same thickness offcourse) in between. The lengh is choosen that way that my harness is about 2 inches longer than original. That way there will be more "liberty" to flex.
Last but not least think of this : as everything is accessible, verify also the situation in the RH rubber. You'll find ther the wiring for the rear window heating and more important, a clear plastic tube (with nylon tissue in it) often hardened and cracked and leaking or pinched, for the washing fluid.
I put a black and soft rubber tube in place. Haha, when you pull the old tube out be shure to have a wire fixed to one end. Guess why ( and how I found out )...
And at last... what about replacing the dampers the same time?
I didn't and still regret so that's on the program this summer as well as to take out left & right third window to put a new seal in. All the W124 wagons I know of, are leaking there...
Well Bob, I hope this will help you out. Take it easy : the nicest thing about this repair is that you can take your time because you can drive the car anytime with the unfinished repair!
If you have an EPC you can see that clamp in group 54 - electrical equipment and instruments - figure 570 - electrical parts used for rear panel door item 33. The partnumber of the cable harness is A 124 540 37 07 if you prefer to replace it.
Good luck and share you experience!

Danny
Reply With Quote
  #7  
Old 02-04-2004, 01:24 PM
pesuazo's Avatar
Registered User
 
Join Date: Oct 2002
Location: Near Raleigh, NC
Posts: 580
uberwagon:
The pump is located in the same place in your wagon.
Under the rear seat, passenger side.
To test the pump, remove and connect dirct voltage battery.
I can e-mail you the whole procedure right off the manual. You will need acrobat reader.
__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified
Reply With Quote
  #8  
Old 02-04-2004, 03:21 PM
Registered User
 
Join Date: Jul 2002
Location: Soggy Seattle
Posts: 30
Danny, Thanks for the detailed description! That will be very helpful. Maybe I can even get my rear window washer working again.

pesuazo, I printed off the pump test procedure yesteday but thanks much for the offer.

I'm not going to get a chance to work on this till the weekend. I'll post what I find.

Thanks,
BoB
__________________
1988 300TE
1991 Miata
Reply With Quote
  #9  
Old 02-10-2004, 11:17 AM
Registered User
 
Join Date: Jul 2002
Location: Soggy Seattle
Posts: 30
Just a quick update. I finally got a chance to start working on the problem last night and the first thing I noticed was that the rear passenger side footwell was soaking wet. After pulling up the carpet I can see the wire channel that pesuazo's post pointed to. Didn't get any further but I'll need to take a look at that wiring. And of course now I need to figure out where the water is coming from!
BoB
__________________
1988 300TE
1991 Miata
Reply With Quote
  #10  
Old 02-15-2004, 07:25 PM
Registered User
 
Join Date: Jul 2002
Location: Soggy Seattle
Posts: 30
Well I've made some progress. First, I cleaned out the drains below the hood hinges. They were well clogged and, based on some other info from this forum, this can lead to water in the interior. I did find some water under the fron passenger floor mat. Since it's winter in Seattle I've already have several chances to test it and so far it looks like it's staying dry.

Second, I now have my central locking working as it did before. The problem was bad connections in the channel under the rear passenger side carpeting. There are three splices that impact the central locking. I cut off the splices, stripped the wires and twisted them back together and it worked. I'll need to make a better connection before I put everything back together.

I do appear to have some problems though. Ever since I bought the car I have only been able to lock and unlock all doors from the driver's door. Locking or unlocking passenger side door or the tailgate had no effect. In looking at the wiring diagram and poking around I appear have two problems.

The ground "supply" for the passenger side and tailgate actuator switches is suppose to be supplied by S8/2, the warning buzzer switch. This switch does not seem to be working or the ground side of the switch is not connected. I have not started trying to track down the connection for this. Apparently the switch is on the ignition switch and the connections are under the drivers side left kick (X30).

The other problem is that there appears to be a short in the passenger side actuator switch. The brown/black wires connecting the locke side of the passenger side and tailgate actuator switches and ground supply wire (from the warning buzzer switch) is sitting at about 7 volts when the passenger side lock is in the locked possition. If I disconnect the tailgate and ground supply wire, the wire from the passenger side actuator switch is still at 7 volts. If I move the passenger lock to the open position, the voltage on the brown/black wire goes away and the signal wire from the actuator is at 12V, as it should be.

BTW I connected the brown/black wire from tailgate actuator switch directly to ground (which is how it was connected beginning in 1990 I guess) and it works fine. I can lock and unlock all the doors from the tailgate.

So, I this point I think I'll just wire it back up so that the tailgate switch works. I don't know how hard or expensive it is to replace the actuator in the passenger door but I sure do hate taking those inside door panels off. Not much point in trying to get the warning buzzer switch working until I can get the actuator fixed.

Thanks again to pesuazo for pointing me to that wire channel under the carpet.

Any other suggestions or comments welcome.

BoB

__________________
1988 300TE
1991 Miata
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 09:24 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page