Having some weird electrical problems. The back up lights are not working. The interior panel lights (speedo) dim sometimes. The trip computer went into 24hr mode and then back.
Brand new battery dies if left for 24 hours. What could be draining the battery? on 1994 BMW 540i
2 answers 2 comments
I would start by checked all the doors and trunk to make sure lights are off. Might have a big short somewhere making battery draw. Would take to a repair shop and they can install a meter to battery and start removing fuses to see what is making draw
It turned out to be something that took a master BMW mechanic 2 days to find. After pulling the primary fuse box and the secondary fuse box and going thru all the relays there was still a big draw. It seems that even though it was still functional one of the seat motors was in the constant "on" position. We have a combined 50 years of experience working on BMWs and neither of us had ever seen that. Replace the seat motor and problem solved.
you have a constant pwr draw, have it ck'd out
Turned out to be (after 20 hours of work) a shorted out seat motor. It worked but was alway in the "on" position. Thanks for your input.