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Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 3:24 pm
by dvisor
I wonder if someone can help me with an auto electrics problem? I've obviously wired something up wrong.

What I want is for the BMW clock to run off my leisure battery all the time, and the clock light to only come on when the vehicle lights are on.

The problem is that when my vehicle headlights are off, the clock works. When the vehicle lights are on, the clock stops until I turn the lights off again.

This is how I've cabled it up:

The clock feed comes directly from the leisure battery.

The clock light feed comes from the same circuit that powers the bulb immediately behind the gearstick. So this is coming from the starter battery side.

There must be something wrong with my logic, but I can't see what it is. Can anyone guide me in the right direction?
Thanks

Re: Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 3:31 pm
by 321Away
just checked on a 01 plate and the gearstick panel lights up with ignition, you need to find an illumination cable (red/black stripe), stereo wiring has everything you need (if you have stereo feed changed over to LB)

Julian

Re: Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 3:39 pm
by dvisor
Thanks for the response. On my 97 auto, the bulb behind the gearstick only lights up with headlights on, not just ignition (I believe many people use the same feed for the white plasma dials). I'd rather keep the wiring here if at all possible, but if it's never going to work like that, I'll switch it to the stereo wiring.

Is it not possible to power the clock from the LB circuit and the clock light from the SB circuit?

Re: Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 4:42 pm
by dvisor
Found the problem - all sorted now

Re: Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 4:59 pm
by missfixit70
Don't keep us in suspenders :wink: , what was the problem?

Re: Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 5:06 pm
by dvisor
Aw! I'm too embarrassed to say :oops:

The earth and clock light feed were reversed. Switching them around and spinning the LED bulb 180 degrees did the trick. The clock was effectively getting two 12v feeds but still working, so I guess it was earthing through something else further down the line.

Now I'm wondering if this contributed to another problem I've had with the electrics (starter battery running down after about 10 days of laying idle).

Re: Auto electric problem - Clock stops!

Posted: Sat Jul 23, 2011 5:19 pm
by missfixit70
I was wondering if that was the issue, but wasn't sure if the clock would have worked in the first place :wink: easy mistake to make & a simple cure.