Re: basic (?) electricity

[Huw Powell <human@nh.ultranet.com>]

> What am I missing here?  The trunk light isn't working.  A DMM connected
> across the empty socket terminals shows 12.4 V.   But when the bulb is
> connected either in series or in parallel, the voltage drops to zip.  However,
> when the ground is transferred from the neg terminal to a chassis ground, the
> bulb goes on and the DMM shows 12.3 V.
> 
> Can anybody explain what is happening, please?

You're either shorting out the socket when the bulb goes in (should blow
fuse...) or more likely somehow breaking the ground connection to the
socket when the bulb is inserted.  have fun!

-- 
Huw Powell

http://www.thebook.com/human-speakers/audi-main.htm