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1995 SL 500
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Recently purchase a 1995 SL 500. Never had a problem with battery even after several weeks of sitting. Battery went dead with out warning. Dash was locked so I can't get manual out of door compartment and cannot access battery behind driver seat because it is also locked. How do you jump start this vehicle? Is it better to call service? I know there are things to be reset?
 

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SL500 03, GR.CHEROKEE LTD 01
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battery is in the trunk, not behind driver's seat. do you have access in the trunk?

george

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1995 SL 500
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Discussion Starter #3
yes I can get in the trunk but do not see where the battery would be/ Is it by the spare tire?
 

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'03 SL500, '03 SL55, '97 SL320, (2) '91 300SL, (2) '91 500SL, '00 S500 -- all for sale
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varlerw2 said:
okay i found the battery. what precautions should i be aware of?
I jump-started a '90 300SL on many occasions and never had any problems. If you connect the cables properly, I don't see how there could be any risk at all. That said, M-B cautions never to jump-start an R129, and some people have reported damaged electronic components resulting from doing so. [Edit: WRONG! M-B does not caution against jump-starting an R129 from another vehicle.]
 

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So if MB said don't jump start, how else you get the car started? I have heard many said the same thing about electronic modules, but I would think the MB engineers must be aware of such issues, or is it just a myth? I find it difficult to think jumping a car would do that much damage. Then again, I don't want to find out the hard way. Injury mind wants to know.
 

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1992 SL500
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I had my battery low the other day (still turning engine over, but slowly) so I disconnected one battery terminal and charged the battery slowly with a trickle charger. This is 1 alternative to jump-start, particularly if you are at home and not in a hurry...

I have a friend who said he jump-started his R129 and damaged the computer (?!) which he subsequently replaced.... perhaps bad luck - i cant imagine he did it incorrecly, he is a mechanic.

If anyone else has had expeience with jump-starts, let us know - it is interesting to know if the no-jump-start is fact or urban legend.

rgeards Steve.
 

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elau said:
So if MB said don't jump start, how else you get the car started?
I must have been wrong about M-B advising against jump-starting from another car. I looked at 2 different owner's manuals and they both describe the standard procedure as outlined in the link that George posted above.

So what about the numerous reports of people losing soft top controllers, roll bar controllers, etc.? Maybe some of them used one of those battery charges that has a boost feature for jump-starting. I think that it is accurate to say that some of these charges can very definitely damage components if used in this manner.
 

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1990 500SL
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I was also worried about this don't jump start rule but my mechanic said no problem as long as you connect terminals properly and not with the donor vehicle engine running. I then did this expecting all sorts of problems (I trust my mechanic ) but hey the car started and away I went and no problems. I would not be worried in future if I need to jump start the car hopefully it doesn't need it.
 

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instrument cluster

well i don't know if it's true or not but i just got my 91 500sl out of the body shop the other day after being in there foe a year and they jump started it a couple of time and now nothing on my instrument cluster works but the coolant temp. and my freind ( who works on merc. and bmw only) came over the other day to help me diagnose the problem and he said thay if you do a fast charge or a start position on your charger that you could blow the voltage drop resistor on the cluster, which we think that happened to mine . all fuses are good in mine and it worked fine before i took it in so ?? but he said you could use a jump box or trickle charge and it should be fine. so anybody know how to fix a cluster??? thanks
 

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Until reading this thread my paranoia was only limited to the dash flash and hydraulic leaks. Now, it seems that jump starting must be added! Question: since the battery is in the trunk, where would you recommend attaching the negative cable? Does it make sense to connect this last using the R129 negative battery terminal and an appropriate grounding spot on the donor vehicle? Also, as I basically just start and run a few miles in perfect winter weatheronly, I was thinking of buying a battery tender. Is this a good idea? Thanks as always,
Ron
 

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As you suggested, just ground the cable of the chassis of the non-R129 car. A battery tender is a good idea if you find your battery is going flat from disuse.
 

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OK, maybe I am stupid. What do you mean by grounding when jump start? There are two clamps, one red and one black. You clamp them accordingly to the batteries. Where is the grounding you talking about? I don't have a third clamp on any of my jumper cable. Would you mind clear that up for me?
 

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When you jump a car, you connect the "+" terminals of the two batteries directly. However, you do not directly connect the "-" terminals -- on one of the two vehicles you complete the circuit by clamping the cable to the chassis instead of the battery. Since the R120 has no convenient grounding points in the trunk, rfpmoxie was wondering if you could make the chassis ground connection on the car with the good battery, and I replied "yes".
 

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bobterry, are there any 'points' in the engine compartment that you can be used instead (like in the porsche 928), or one has to have access to the trunk / battery?

george
 

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Yes there is, George. It's the X11/4 terminal block located under the protective cover shown in the attached photo.
 

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1995 500SL
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After reading these posts, I still am not sure (comfortable) with the jump/ don't jump issue. Knowing that a power surge might cook some VERY expensive component keeps me from using those jump cables. When my battery died, I took it out of the car, had it charged and re-installed, only to find out there was a bad cell in this older battery; so I replaced it. I don't know what caused others to have problems after a "jump" - as for me, I am not ready to chance it.
 

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1995 SL 500
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Discussion Starter #20
thanks and more info

I want to thank all of those who offered advice. I was still skeptical and went on the MB factory website to find out more info. When I searched "dead battery" I found out that MB offers free roadside assisatnce to any MB owner regardless of when a where you bought the car. See http://www.mbusa.com/care/client-care/roadside-assistance.do
I called and the local MB dealer sent a service rep. He tested the battery and it showed zero amps. the battery was old and I opted to have it replaced. He replaced the battery on the spot for the cost of the battery. A deal!

This sis a great option to those living in proximity to a dealer.

Bob
 
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