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A4 +ve?

Posted: 22 Mar 2025, 21:33
by MarcoT3
Hi all, does anyone know where the A4 positive in dash wiring loom noted below is in reality in the van? Thanks :D

Image

Re: A4 +ve?

Posted: 22 Mar 2025, 22:52
by Robsey
I have looked at various versions of this, and there is only a minor difference in terminology.

Most diagrams say (A4), and others say (22).

Those that say (A4) say "Dash Panel Wiring Loom", which infers anywhere under the dash.

Those that say (22) say "In Insttument Panel Wiring Harness"

Both mention the 58b circuit, which is the dimmed illumination from the rheostat on the light switch.

I can only assume that there is a single spade connector somewhere between the instrument cluster and the light switch.

The clue will be a grey wire with a blue stripe / tracer on it.

Re: A4 +ve?

Posted: 23 Mar 2025, 23:42
by MarcoT3
Thanks I’ll try trace it and see if I can find it!

Re: A4 +ve?

Posted: 24 Mar 2025, 06:51
by ZsZ
IIRC left side beside the heater box there is a crimped junction on the grey/blue dash lighting wires that is A4
Might be different on RHD vans

Re: A4 +ve?

Posted: 24 Mar 2025, 08:52
by Aidan
FYI I have a rhd dash loom in my hands, can see the power from Blue1 to fuse S50 in holder on top of fuse board, and the grey blue wire off the other side of the fuse and can see the various grey blue wires that go to the various backlit switches/display and the dash module but can't see where in the loom they are all joined together, but I'd be very surprised if the internal joint was at fault unless water has got in big time or someone has modified the wiring previously

what actually is the problem you are seeking to fix ?

Re: A4 +ve?

Posted: 24 Mar 2025, 12:39
by ZsZ
Image

LHD van. The black metal part is the steering column bracket beside the master cylinder, the black pipe in the front is the heater control wire.

Brown is the earth junction 81, grey/blue is instrument backlight A1


E D I T:
here on the right side of the master cyl. you can see one single grey/blue. it goes to the junction pictured above:
Image

Re: A4 +ve?

Posted: 24 Mar 2025, 19:12
by MarcoT3
Thanks Guys very helpful, 

The problem I’m having is my blower/wipers/radiator fan are only intermittently coming on when i move the fuse panel, I have already cleaned all the ground crowns and connectors at the back and I’m trying to figure out what else they have in common. I’ve isolated it and The problem is definitely in the fuse panel as when I move it the slightest bit they come on and off!

The x relief relay has a number 53 instead of the 18 (which I have ordered), not sure if this would matter as everything was working up until last week!