diagnosing a mystery current drain

Kieran Lavin kieran at kieranlavin.com
Tue Nov 18 11:35:44 CST 2008

On Tue, 18 Nov 2008 11:28:17 -0600, Lawrence Weeks wrote

> One quick question though: do your hazard lights work? Is the switch
> ok? I've found in my cars that leaving that switch disconnected (or 
> is it the rear defogger switch?) causes the battery to drain. When I 

This sort of makes sense to me now... I think it's the defroster switch.  My 
rear defroster doesn't work.  In the B14, the defroster goes through some box 
tied to the keyless entry.  My car was broken into last year and the yokels 
that fixed the car didn't fix the keyless entry properly.  I was just getting 
to the point that I was going to diagnose and fix my rear defroster when I 
got the new car so I never bothered.  The car mostly sees the track so I 
don't really need the rear defroster.  But your comment now makes sense as to 
why I've got an unknown draw and have to leave the car on a battery tender 
now.  It didn't draw power nearly as fast as David's experiencing though.  If 
the car was driven recently and a lot, it'd take 2 weeks to go dead.  If I 
took it off the tender and drove 5 miles and let it sit, it'd be 4-5 days to 


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