Evening all. New to the site, recently brought a 1985 ducato motorholme as a bit of a project.

First thing iv discovered are the electrics are a bit of a mess.

But first thing I'm after sorting is the glow plugs.
They've been wired to push button switch rather than the normal way. iv had a quick look tonight its been wired to a separate relay.

First thing I'm struggling with: At the glow plugs where the feed goes to them it has a constant negative. Then when the button is pressed activating the relay this turns to a +ve feed. why have i got a negative feed before the relay is activated??

Thanks

Also has anyone got a wiring diagram so i can re-wire it back to its orginal way