12 42 540 Replacing safety battery terminal (SBK)

WARNING: This page is about a different car, the 2002 BMW Z3 and 2001 BMW Z3. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Observe safety regulations. Refer to AIR BAG SAFETY PRECAUTIONS for 2001 models, and AIR BAG SAFETY PRECAUTIONS for 2002 models. Investigate cause of triggering of safety battery terminal. To do so, read out fault memory of airbag control unit. Note fault messages stored in memory. Rectify faults. Then clear fault memory.

Use of safety battery terminal:

From 4/99 in E36/Z3.
In each of following new Series.

The different models have different installation locations:

Battery In Engine Compartment:

Safety battery terminal is replaced with cable up to battery positive support point.

Battery In Luggage Compartment Behind Side Trim Panel:

Remove side trim panel.

Fig 1: Removing Side Trim Panel

Courtesy of BMW OF NORTH AMERICA, INC.

Follow instructions for disconnecting and connecting battery. Refer to 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY .

Disconnect and cover battery negative lead.

Release front side trim panel partly and fold forward.

Fig 2: Releasing Front Side Trim Panel

Courtesy of BMW OF NORTH AMERICA, INC.

Battery In Luggage Compartment Under Floor Trim Panel:

Follow instructions for disconnecting and connecting battery. Refer to 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY .

Fold back floor trim panel (1).

Lift cover (2) on battery negative lead.

Fig 3: Lifting Battery Negative Lead Cover

Courtesy of BMW OF NORTH AMERICA, INC.

Disconnect and cover battery negative lead (3).

Release nuts (4).

Remove battery cover.

Battery In Luggage Compartment Under Spare Wheel:

Remove spare wheel.

Release screws.

CAUTION: Do not kink air pipes.

Set air supply system (1) to one side.

Fig 4: View Of Air Supply System

Courtesy of BMW OF NORTH AMERICA, INC.

Follow instructions for disconnecting and connecting battery. Refer to 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY .

Disconnect battery negative lead.

Disconnect supply cable (1) for vehicle electrical system.

Fig 5: Removing Supply Cable For Vehicle Electrical System

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Remove faulty fuses and carry out troubleshooting.

CAUTION: Pay attention to interface. The repair cable is always a standard length. The heavy-current connector of the repair cable has a larger diameter than the battery positive lead. In some Series (e.g. E46 touring), the heavy-current connector of the repair cable can lead to installation problems. This is the case when the interface is in the area of the close-fitting trim panels. Find matching interface (e.g. approx. 10 cm behind rear seat backrest in E46 touring

Lay repair cable parallel to battery positive lead.

Mark interface of battery positive lead at end of repair cable.

Fig 6: Marking Interface of Repair Cable To Battery Positive Lead

Courtesy of BMW OF NORTH AMERICA, INC.

Release cable ties (1).

Fig 7: Releasing Cable Ties

Courtesy of BMW OF NORTH AMERICA, INC.

Disconnect plug connection (2).

CAUTION: Do not use bolt cutters or similar tools to cut through the cable. A cable end that has been squashed flat will no longer fit into the clamping sleeve.

Saw through battery positive cable at marked point with an iron saw.

Fig 8: Identifying Positive Battery Cable Cut At Marked Point

Courtesy of BMW OF NORTH AMERICA, INC.

Strip insulation - length (A) - from cable end.

Distance (A) = 15 mm.

Fig 9: Identifying Strip Insulation Length From Cable End

Courtesy of BMW OF NORTH AMERICA, INC.

Push heavy-current connector (1) over stripped cable end and screw into position.

Fig 10: Pushing Heavy-Current Connector (1) Over Stripped Cable

Courtesy of BMW OF NORTH AMERICA, INC.

Push shrink-fit hose (3) over repair cable.

Screw threaded sleeve (1) of repair cable (2) to heavy-current connector.

Fig 11: Installing Threaded Sleeve Into Heavy-Current Connector

Courtesy of BMW OF NORTH AMERICA, INC.

Push shrink-fit hose (1) over connecting point and shrink on with a hot-air blower (2).

Fig 12: Installing Shrink-Fit Hose Over Connecting Point

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Heat up shrink-fit hose until it has settled completely around the connection point.

When laying the repaired battery positive cable, observe the following:

The shrink-fit hose must not be scuffed during any movement.
The repair cable must not cause any disturbing noises during driving operation.

Fig 13: Identifying Shrink-Fit Hose

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Offsetting cutting line by approx. 10 cm produces excess length of battery positive lead (1). Lay battery positive lead (1) without kinks or abrasions. (Shown on E46 touring.)

Fig 14: Laying Battery Positive Lead Without Kinks Or Abrasions

Courtesy of BMW OF NORTH AMERICA, INC.