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View Full Version : LKM? Interior lighting issue...


MTechnik540i
06-25-2007, 08:38 PM
Hey fellows,

Just lately we've noticed the M5 doing this unusual deal where interior courtesy lighting completely shuts off while starting the car...After a little pause it then goes back to normal.

Anybody have any clues? My initial thought was powering issue, but this seems different, as the lights don't slowly dim, they just shut off all the sudden and immediately reappear.

Any help is appreciated!
Chris'91'525i
06-25-2007, 09:11 PM
Don't most cars have in interrupter or power cutoff circuit (forgot the technical term) on the starter.
That basically cuts all power to anything thats on, and directs all the battery power to the starter. And after you release the key when car starts, what ever that was on before goes back on.
Blitzkrieg Bob
06-25-2007, 09:22 PM
Don't most cars have in interrupter or power cutoff circuit (forgot the technical term) on the starter.
That basically cuts all power to anything thats on, and directs all the battery power to the starter. And after you release the key when car starts, what ever that was on before goes back on.

that could be what you're looking for
MTechnik540i
06-26-2007, 07:25 AM
that could be what you're looking for


So, this is completely normal?

It's very possible that I just now noticed that it does it.
MTechnik540i
06-27-2007, 11:23 PM
So, this is completely normal?

It's very possible that I just now noticed that it does it.

?????
Chris'91'525i
06-28-2007, 08:44 PM
So, this is completely normal?
It's very possible that I just now noticed that it does it.

Yes it is completely normal for the lights to go out when starting the car, and then go back on after the key is released form the start position.
Thats the purpose of the 'Unloader relays'. It allows the starter and ignition system to get full battery power during start up.
Try it with your head lights and heater/AC blower on full and anything else. They should all lose power at start up, and then go back on after started.
Alan_525i
06-29-2007, 09:40 PM
My E34 does not loose power to the radio and lights when starting. Never noticed about the blower etc though.