Interior lights and Fuse 38 Blowing

[MarkJL]

Hi,

I have been looking into a fault I have on a A4 B6 Cab, where the interior lights stop working which is due to Fuse 38 (15A dashboard fuse panel for Comfort Control Electronics) blows.

I have found that the Blue/Black wire going to the fuse box (switchable 12V) has a short to ground (about 500 Ohms). The Wire to the CCM (under the passenger carpet) from the fuse box is fine, and I believe the CCM is fine also. Incidentally the foot wells are dry as a bone, so no leaks from the engine bay.

If I remove the cables from the Central Electronics Control module under the drivers dash panel where the relay panel is, and put them back the short goes, but having metered the wire, it doesn't go to any of these connectors.

I pulled relay 167 (Fuel pump) and the wire buzzes through to here but I guess this is a common 12v.

Any ideas where this elusive Blue/Black wire goes to? I'm guessing a relay but can't find the wiring diagrams that relate to this anywhere, and (not wanting to sound stingy) don't want to buy a manual for one page.

Just to prove everything was working, I put a 20A fuse in quickly, and although everything works, it obviously got hot, and although in for only 20 secs I could smell plastic getting hot smell.

Help please.

 

[MarkJL]

Ok, small update if anyone can shed a bit of light (forgive the pun) on this as it is becoming OCD to sort it out.

Having finally found a circuit diagram, fuse 38 appears to come from the Load Reduction Relay. Looking up this on Google mechanic, it looks like it is numbered 213 on the relay panel underneath the steering column. The problem I have is that I don’t have this relay underneath the steering column, only 167, 53 & 370. Where is this likely to be, it must be somewhere??

 

[MarkJL]

Sorry, my bad. Uploaded the correct diagram with fuse 38 on it, my question is where physically are points 12 for the wire to the fuse panel, A57 - Plus connection 2, and 501 - threaded connection on relay panel.

 

[MarkJL]

Changing tack a bit on this (driving me nuts). I have invested in the Haynes manual, and having tried a couple of things, I'm back to looking at the CCM itself.

Before I do anything with the module, it refers to an earth point E9 b which also goes to imthe same plug as the fuse which keeps blowing, but im not sure where this earth point is.

Can anyone point me in the right direction please?