I disconnected the negative

[engatwork]

battery cable to prevent anyone from driving my E320 while I am at work. Will this cause any problems other than having to reset the clock everytime I drive it.
Thanks for the advice.
Jim

[stevebfl]

Jim,

I really don't like what you are doing. It just isn't natural for all the control units to get their memory wiped every day and be rebooted. All adaptations will have to be relearned. I worry about the original programming.

It is likely that you will eventually set codes in the SRS and/or ABS. All the systems have to communicate with the CAN and it is very sensitive to voltage fluctuations.

If you really want a cut-off switch I can think of other less risky methods. What happened to the key? (bg).

[Pbalias]

Sorry, this wont answer your question I dont think but, What are people doing driving your car while you're at work??? Co-Workers are driving it???


???????????????????????????????????????

PEter

[Q]

You sound like the perfect customer for that little device that attaches to your battery terminal. It has a knob and a fuse. When you unscrew the knob, the current for the clock/computer memory still flows through the fuse. If someone trys to crank the car without the knob, the fuse blows and breaks the circuit. Performance Products has them in their Mercedes catalog.

I think they have one of those battery devices with a remote control??? It allows enough juice to flow without disrupting the electronics.

[David C Klasse]

I don't get it either?? Are you going to work, parking, going into the trunk, and then just disconnecting the battery? Do people think you are nuts? (no offense, i would if i noticed this to be a repeated pattern) Why do you do this? Can't you just lock it and keep you key on you and no one would drive you car? Who are you worried about drivng you benz (the wife??? i thought???). Why don't you just get an alarm or a cut off switch? WHY ISN'T The key just good enough?? DETAILS, EXPLAIN! I'm enlightened...

I think there is a kind of ECU box from autoauthority. I think that is the name. Don't remember all the funcitons, b/c it was awhile back.

[Ashman]

Why can't you just put a remote starter cutoff switch on the car or a toggle switch on the starter wire.

Simple, and battery stays connected.

Or why not just pull the coil wire from the distributor?

There are much better ways of disabling a car than the battery.

Alon

last time I disconnected my S500 negative battery cable, it caused my alternator mess up, so I replaced the new alternator.....

[ymsin]

Hi Jim, I think its wise to read what the gurus have written here coz regular dismantling of the negative cable might do lots of damage to your electronics. Its ok for the older model MBZ but be more cautious on the 210s.

[jylee]

Not only the clock. But the radio code, seats, steering wheel. Also the Free alarm on the car is disabled.

You will also need to open the hood, find the wrench to connect the cable, not to mention, you also need to disconnect when you EXIT you car.

jack

Jim,

I will not second guess your reason for doing this like others have.

I believe the best suggestion you got here was to use the disconnect with the fuse. This allows all memory to be active while the main line is virtually disconnected. This would also keep your security system operational.

If you can't find one of these gizmo's, all you have to do is put one of the disconnects in series with a battery cable and put an inline fuse around it with about a 1.5 or 2 Amp fuse. If someone does hit the starter, it will immediately blow the fuse. At that point you will be no worse off than if you had disconnected the battery, because all memory will be lost and you will have to risk a surge when reconnecting. Also you will have to replace the broken window that the thief caused.

I would suggest that you take Steve Brotherton's comments to heart. Constant voltage spiking could eventually cause problems not to mention that the engine will have to "retrain" each time memory is cleared.

Good luck,

[engatwork]

and keep the battery negative hooked up. I have decided to just take her key away. It is the wife that tends to want to drive it and I am paranoid about it being driven on trips of less than 15 minutes which are what her trips consist of.
thanks everyone
Jim
'85 300D
'95 E320
'97 CRV

[Stuart S]

I drive my '93 600SL only on nice weekends. I want to keep the battery from running down when not in use, which can be for 2-3 weeks or longer. The Precision Auto Designs catalog includes 3 items, but I don't know which would be best. They sell: (1) a fused link battery switch for $19.95, which they claim is great for extended storage; (2) a Schumacher 1.5 amp charger for $34.95 that automatically switches on and off; and (3) a SureCharge II full floating charger for $34.95 that they claim cannot overcharge and can be left connected. I'm concerned about using either of those chargers with the negative terminal connected because the owner's manual says to disconnect it when charging the battery to avoid damaging other electrical components. Am I better off with just the fused switch? Or is the output of those chargers so small as to not cause any damage? If so, which charger would be best? Thanks for your advice.

[David C Klasse]

Stuart,
I still think your battery is fine left connected when not in use for only a few weeks at a time. Every time the battery is disconnected, the computer has to "learn" everything again. Not good for the computer, and I'm sure won't reduce your longevity by much at all. Best bet is to leave it as it is, IMHO.