Repair e39 Light module. BTS426L1 alternative component for the BMW E39 LCM (Light module)..
June 18th, 2007 by 
ltz
So it happened on my e39 as well.. The right headlight just would not shut off. Even if the car was turned off and locked, the right headlight was still on. It’s an well known problem, but it seems the components are getting harder and harder to get ahold off. The first replacement component, BTS 426 L1 (Farnell is out..) The suggested alternative components were’nt availiable to swedish non-company customers (VN21 availiable from ST. VN21). Instead, the only component I could get ahold of was the BTS426L1 surface mounted (see product image). This component was not supposed to be mounted this way, but mine have been used this way some 600 km’s now and seems to be working.
Have a look at the images from the operation.
Allright, the process should be visible on the pictures..
Update:
Posted in Uncategorized | 
June 18th, 2007 at 21:23
The soldering to the surface mounted component is secured with melting glue before pressed against the cooling element.
June 18th, 2007 at 21:30
.. the cables solderd to the board is also isolated with melting glue in order to keep them away from the metallic cooling element..
November 24th, 2007 at 01:02
Another thing I realized today, while repeating the steps above. The heat sink isolation must be in proper order. If the backside of the component touches the heat sink without a isolating tejp in between, the component will burn.
Just a tip..:)