Battery cable problem

[Mike22 in MD]

During recent battery change on my 2001 CiC, the black wire with yellow connector came loose on positive cable harness and I cannot get it reseated. I understand this cable is part of an explosive disconnect system integrated with air bag deployment; and here my "knowledge" ends. Can I safely reconnect new battery without this cable? Can I purchase a replacement cable w/o buying the whole harness assy? Other thoughts, advice.

Tks

[MillerTime1nine]

Reseated back on the battery? I tried to find a picture but i cant find one.

[peterv]

Sorry, but you need to replace the entire harness assembly.

[Mike22 in MD]

OK; replace the harness. Can I intall the new battery without the SRS cable to at least drive it to the dealership?

[02325]

yes you can, but the airbag light will come on. nothign else will happen. and the positive cable harness cost about 300 bucks.

[Sean S]

Can someone explain how this explosive charge goes off so easily and why it can be triggered during a simple battery replacement / amplifier install? This is the second time this week I have seen someone with the same problem. What is causing these things to go off and how do we prevent it?

[slvrXI]

Can someone explain how this explosive charge goes off so easily and why it can be triggered during a simple battery replacement / amplifier install? This is the second time this week I have seen someone with the same problem. What is causing these things to go off and how do we prevent it?

Idiots. I've replaced many bmw batteries and installed systems 4 times on my E46s... Positive cable first, then negative cable. idk? Some people just shouldn't touch a car?

[Sean S]

Idiots. I've replaced many bmw batteries and installed systems 4 times on my E46s... Positive cable first, then negative cable. idk? Some people just shouldn't touch a car?

By "+ first, - second" I assume you mean the traditional way of doing it safely:

Disconnecting the battery:
First remove ground, then remove positive cable.

Connecting the battery:
First connect positive, then connect ground.

Correct?

How does this charge go off? Is it from an accidental short when removing the + cable, or from jerking/dropping/impacting the cable? How do you safely add additional positive cables (for example amplifiers, power inverters, other electronics) without affecting this system?

Thanks for the advice so far

[slvrXI]

There is no reason for the charge to go off unless you somehow jump a positive wire to the BST connector... I have 2 extra cables coming off of my terminals, just make sure you don't short anything, and watch where your wires are going. Carelessness is the only way to explode that thing (although anything is possible...) Its on the same circuit as your airbags, it has the same type of igniting mechanism as any airbag... It has the same probability of exploding as an airbag. And if you disconnect it without disconnecting the battery first, then you screw yourself. Same thing as an airbag, you don't disconnect/reconnect airbags with the battery still connected.

[Sean S]

Agreed. With the E46 I have made it a habit to ALWAYS completely disconnect the battery before I start working on anything electrical - even things like changing switches. These cars are so intricately designed that any little modification while the battery is plugged in can at the very least throw a code you can't get rid of.

Step 1: Open trunk
Step 2: unplug negative cable on battery
Step 3: Unplug positive cable on battery
Step 4: work on car.

[danewilson77]

Agreed. With the E46 I have made it a habit to ALWAYS completely disconnect the battery before I start working on anything electrical - even things like changing switches. These cars are so intricately designed that any little modification while the battery is plugged in can at the very least throw a code you can't get rid of.

Step 1: Open trunk
Step 2: unplug negative cable on battery
Step 3: Unplug positive cable on battery
Step 4: work on car.

This is opposite as to how you wrote it in your comment above....

Positive first......need to swap step 2 and 3

[Sean S]

Why would you remove the positive first and then then negative (this pertains to REMOVING a connected battery)? If you remove the ground first, you cannot possibly short anything out. Wrench slip while removing ground first, nothing happens (body is grounded). Wrench slip while removing positive first, you short something out. Is there something I'm not aware of? This has been how I've always been taught to remove the battery:

Disconnecting the battery:
First remove ground, then remove positive cable.

Step 1: Open trunk
Step 2: unplug negative cable on battery
Step 3: Unplug positive cable on battery
Step 4: work on car.

I'm sorry Dane but I'm confused how I have it opposite between these two posts?

[danewilson77]

Step 2, above you said to remove negative cable first (post at 0456)

Post at 0144, you say to remove positive cable first....