1994 600SL Electrical Problems after replacing Battery

[pepepotamo]

My battery went dead and, upon replacing it with a new one, the following problems appeared:
1) The soft top does not operate (switch light blinks)
2) The roll bar does not operate (no lights)
3) The ABS light comes on and, after a while driving it goes off. Cycle starts all over again next time vehicle is run.

I have been reading through the threads and cannot find where the OverVoltage Protection Relay is located for my vehicle in order to check it. I have tried the following:
"resychronizing" the windows, no effect
tried leaving the car overnight with the battery disconnected, no effect
tried checking all fuses, all have continuity
tried disconnecting the soft top controller and reconecting it, no effect
tried grounding the pins 21 and 22 of the round diagnostics plug (data link connector), no effect, nor can read any codes.

Please Help !
Last time I replaced the battery, the dealer charged me $350 to get the car back into shape (no part was replaced). This seems crazy! that just to replace the battery the whole car's electrical system goes haywire.

I have owned this car since new

[Carlos Serrano]

Mine is a 99 SL but after I replace my battery I had to start the car turn the steering all the way to the left till it stop hold it for 3 seconds and turn it all the way to the right till it stop and hold it for 3 seconds to resync the ASR, the roll bar just hold the button for a few seconds till it blinks to re-sync and finally the windows all the way up hold them for a couple of seconds till they re-sync with the top on that is, that fixed mine.
Good luck

[pepepotamo]

Thanks Carlos, for the ideas
Truning the steering does reset the ASR, tried the other items for the roll bar and the windows - no change

The lights on the roll bar button and the soft top switch do momentarily come on when the ignition is ON, but they go off and fail to operate.

I do read several error codes on the diagnostics plug (pin 21) but am not able to reset them.

[Carlos Serrano]

Did you try the top with the key in no.2 position in the switch. mine used to operate with the engine running in park and now only with the key in no.2 position, I did a search on the SL forum about this problem and there is a lot of info about this issue, there is one thing that everybody agrees on, the top will not work if the windows are not sync. hopefully is something simple like low fluid in the reservoir, I had that before.
good luck

[Bondavi]

Man...is there a comprehensive manual out there with all the troubleshooting and secret moves one ha to do in order to fix a problem on their 129? If not, I would think someone should make one!

[97slsix]

I wish there were a manual, but haven't found one. All data has good info, but the Mercedes DVD is better for wiring diagrams and the stuff. The DVD was only 130 bux at my dealer and worth it big time. There aren't a lot of technical 129 owners (or at least they aren't posting on the web).

[97slsix]

Just to make sure, here is the sequence for putting in a new battery. This assumes new battery is installed with positive lead connected, neg lead unconnected.



3 Connect ground cable

NOTE: Tighten the nut (5) of the ground line (1) to the specified torque. Perform work described below only when quiescent current retention unit was not connected.

Nut of ground cable to body - 18 N.m

3.1 - turn key to position 2

4 Code radio

* MB Audio 5 (model 168)
* Radio Sound 10, 20, 30 and luxury Audio 10 radio D2B networked
* Becker Mexico .Grand Prix, Europa, Avus
* Hi-Line, Premium with Bose (model 163)

5 Set time at instrument cluster

NOTE: If necessary set time at stationary heater timer.

6 Activate steering angle sensor
(I assume this is the turn wheels left then right thing)

8 Synchronize lamella sliding roof

NOTE: Close lamella roof and keep switch pressed for 5 to 10 seconds .

9 Synchronize power windows

NOTE: Press power windows switch up to the 1st pressure point and, after reaching the upper end position of the window, keep pressed for a further 5 seconds .


I am pretty sure lamella sliding roof refers to other models (not 129 roadster) and can be ommitted.

[tr4me]

had same problem on my 96 SL320 when I replaced the OEM battery. Went thru all the sync stuff, but could not operate top or rollbar.

local independent MB shop assured me that the only way to re-set was connect to MB diagnostic computer.

15 minutes and $80 bucks later I was on my way.

No doubt next time I will jumper in a motorcycle battery to keep system hot while I replace car battery.

[shortturtle294]

I'm curious does your climate control function properly? I've been told in order to get floor and center vent air it needs to be hooked up to a dealer programing computer too.

[pepepotamo]

Already tried all these things. I learned the window sync is for vehicles made after Jan 94. Mine is a 94 model 600SL, made in late 93.

Tried window sync anyway - no change

Here are the trouble codes I can read (for the soft top controller, read from pin 21 in the 38-pin datalink connector): 7, 8, 17, 18, 20, 21, 22, 29
I cannot clear them (tried reading them and then shorting to gnd pin 21 for 8-10 seconds after each code)

hydraulic oil (pump and tank located in trunk) is full, no leaks

I'm running out of things to try... I'll buy the darned scanner before I take it back to the dealer and get plundered and pillaged once again for something that should be a simple reset.

[Carlos Serrano]

Do an advance search, there is a thread by waybomb that reads battery went dead, soft top no worky, ABS light on...there is a good description by tecqboy about roll bar codes and reset procedures and mercedes soft top controller reset procedure on an early R129

[pepepotamo]

PROBLEM SOLVED !!!!

Resolved by clearing the codes, nothing else.

Was extremely difficult to clear the codes by hand, using pin 21 and the procedure of reading, reading, clearing, reading, clearing, etc.

The sequence of clearing the codes was important, the codes cleared from higher codes to lower. I had to read (and patiently wait) each code in the sequence then wait for the last code, clear it, then turn ignition switch off, start again read all the codes until the last one, clear it, ignition off... you get it. When I tried to clear the codes from the first one up it would not work.

In all, solving this problem took over 10 hours of work, no to mention the incredible frustration. All this for simply changing a bad battery.

Looks like an ideal class action case against Mercedes to force them to reset these vehicles for free at the dealer. Just plugging the scanner and hitting "clear" would have solved the problem (at $150 at the dealer...). A problem that is just due to bad design on Mercedes Benz part (a simple "clear codes" button function in the cars would eliminate this inconvenience). It's a shame that the dealers use this as an opportunity to plunder and pillage.