SL/R230: Okay You M-B Electrical Geniuses- A Good Question for You!
03-14-2008, 01:57 PM
#1
Newbie
Thread Starter
Join Date: Mar 2008
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
SL500
Okay You M-B Electrical Geniuses- A Good Question for You!
RE: Cause of M-B SL500 Control Module(s) short
SL500 was taken to a non-M-B brake repair. No elect. problems when it went in the shop.
When they were finished and returned car-- the control module for the Conv. Top/Hard top was bad and showed a fault a short, and a low beam control module was also shorted.
The shop acknowledged that the battery went dead (they stated was bad), and that they either tried jumping it, or ultimately removed it for charging.
A COINCIDENCE... or can damage be done to the electrical system by jumping the battery, or by shorting one of the wires?
Now the manager (for 27 of their stores) is investigating... and is asking all the local Mercedes experts if this can happen. The local dealership in Scottsdale has stated it cannot happen... that there are 3 different fuses protecting the system.... and that control modules go bad all the time!
My guy (factory trained) says that the electrical systems are very delicate and tempermental... and that any slight surge or variance or anomaly to the electrical can fry modules.
Maybe it was coincidental... but that possibility diminishes after their admission of electrical problems (battery being run down) as well as them jumping the battery and then pulling it out... which is more like a "smoking gun" admission.
Anybody have any keen insight as to the likelyhood of the shop causing the damage?
SL500 was taken to a non-M-B brake repair. No elect. problems when it went in the shop.
When they were finished and returned car-- the control module for the Conv. Top/Hard top was bad and showed a fault a short, and a low beam control module was also shorted.
The shop acknowledged that the battery went dead (they stated was bad), and that they either tried jumping it, or ultimately removed it for charging.
A COINCIDENCE... or can damage be done to the electrical system by jumping the battery, or by shorting one of the wires?
Now the manager (for 27 of their stores) is investigating... and is asking all the local Mercedes experts if this can happen. The local dealership in Scottsdale has stated it cannot happen... that there are 3 different fuses protecting the system.... and that control modules go bad all the time!
My guy (factory trained) says that the electrical systems are very delicate and tempermental... and that any slight surge or variance or anomaly to the electrical can fry modules.
Maybe it was coincidental... but that possibility diminishes after their admission of electrical problems (battery being run down) as well as them jumping the battery and then pulling it out... which is more like a "smoking gun" admission.
Anybody have any keen insight as to the likelyhood of the shop causing the damage?
Last edited by 1badmofo; 03-14-2008 at 01:59 PM.
03-15-2008, 06:24 PM
#2
Junior Member
Join Date: Aug 2007
Posts: 60
Likes: 0
Received 0 Likes
on
0 Posts
2003 SL500
Unfortunately it's a bit hard to diagnose now...
since the damage is already done.
After 18 years in the business as a tech and a service manager I have seen some odd things happen that truly are coincidental.This may be true in this case. But I have also seen just as many that were the result of someone in the shop doing something ignorant to the car.
The battery went dead? Who knows they may have put the charger on it backwards reversing the polarity, that isn't going to sit very well with any control module. They allege they took the battery out of the car, by saying that it eliminates any fault on their part of reversing the terminals whilst the battery was in the car. But did they really do that?
From what you describe it sounds like the whole electrical system took a hell of a surge from somewhere other than the cars own system!
The hell of it is you can get as many opinions as Carter has Liver Pills and you'll still never know what EXACTLY happened. You weren't there and neither was I but my vote is that the after market shop probably caused your dilemma. But proving it is the fly in the ointment.
Sometimes the cheap way out isn't that cheap when it's all said and done.
Good luck,
J Tinsby
After 18 years in the business as a tech and a service manager I have seen some odd things happen that truly are coincidental.This may be true in this case. But I have also seen just as many that were the result of someone in the shop doing something ignorant to the car.
The battery went dead? Who knows they may have put the charger on it backwards reversing the polarity, that isn't going to sit very well with any control module. They allege they took the battery out of the car, by saying that it eliminates any fault on their part of reversing the terminals whilst the battery was in the car. But did they really do that?
From what you describe it sounds like the whole electrical system took a hell of a surge from somewhere other than the cars own system!
The hell of it is you can get as many opinions as Carter has Liver Pills and you'll still never know what EXACTLY happened. You weren't there and neither was I but my vote is that the after market shop probably caused your dilemma. But proving it is the fly in the ointment.
Sometimes the cheap way out isn't that cheap when it's all said and done.
Good luck,
J Tinsby
Last edited by J Tinsby; 03-15-2008 at 06:27 PM.
03-24-2008, 01:11 AM
#3
MBWorld Fanatic!
The problem is, the sort of equipment they use to jump start a 20 year-old pickup truck just isn't suited to doing the same for the SL.
First, the SL has two batteries, front and back; the front one runs everything required to start the car, the rear one is for everything else and is well known to go flat when the car is not used for a while.
There's a complex - and expensive - control unit between the two which is all to do with keeping both charged and allowing one to take over from the other, the aim being to be able to start the car after it's been standing for a while.
My guess is that they tried to jump start via the rear battery which is absolutely the wrong thing to do. The manual expressly tells you not to do it and their equipment - which is designed just to deliver hundreds of dirty amps into a starter motor - has probably cooked something. Factor in the grease-monkey ignorance and you are asking for trouble.
Seems to me the brake shop might be liable but why in the world did you take the car into one of these places for brake repair? The SL has one of the most complex - and temperamental - brake systems of any car in the world. The design has been dumped in newer MB models - any may even have been in the latest SLs, I'm not close enough to what they are doing now to know - and there is no way in the world I would let anyone other than an MB dealer touch mine.
First, the SL has two batteries, front and back; the front one runs everything required to start the car, the rear one is for everything else and is well known to go flat when the car is not used for a while.
There's a complex - and expensive - control unit between the two which is all to do with keeping both charged and allowing one to take over from the other, the aim being to be able to start the car after it's been standing for a while.
My guess is that they tried to jump start via the rear battery which is absolutely the wrong thing to do. The manual expressly tells you not to do it and their equipment - which is designed just to deliver hundreds of dirty amps into a starter motor - has probably cooked something. Factor in the grease-monkey ignorance and you are asking for trouble.
Seems to me the brake shop might be liable but why in the world did you take the car into one of these places for brake repair? The SL has one of the most complex - and temperamental - brake systems of any car in the world. The design has been dumped in newer MB models - any may even have been in the latest SLs, I'm not close enough to what they are doing now to know - and there is no way in the world I would let anyone other than an MB dealer touch mine.
03-24-2008, 09:10 AM
#4
Senior Member
Join Date: Nov 2003
Location: Scotland
Posts: 367
Likes: 0
Received 0 Likes
on
0 Posts
2004 SL500, 2007 R350 Sport
03-24-2008, 11:41 AM
#5
Out Of Control!!
Join Date: Nov 2005
Location: OC
Posts: 18,677
Likes: 0
Received 9 Likes
on
9 Posts
a quarter mile at a time
SL may be different from the C-Class, but improperly jump starting and even just disconnecting and reconnecting the battery has been known to blow control modues in the W203.
