[urq] quattro wiring project

[Thatcher Hubbard]

In getting my car running again, I had to dig pretty deeply into the
wiring.  Like most of us, I've had a variety of wiring-related issues over
the years, and since I was getting tired of half of my electrical
accessories not working at any given time, I decided to try to start trying
to reverse engineer all of the circuit paths and get a better understanding
of how the whole system works.

I've actually been taking pictures and trying to put some notes together so
I can share what I do learn with the list.

One of the first things I've done, mostly because it was dead easy, was to
move the radiator fan fuse out of the fuse box.  It has been suggested to
the list before that this might be a good way to lessen the fuse boxes
apparent desire to self-immolate.  I have an e-mail from Tony Lum way back
in 2001 that was the first I saw of it.

His suggestion was to simply wire in an inline fuse holder, which I'm sure
beats doing nothing, but there's a couple of things that seem less than
ideal about that to me.  First off, it would probably means carrying 25A
ATC fuses as well as the 8A, 16A and 25A bus fuses the car already uses,
which really isn't a big deal.  Also, if you were to use a pre-wired
holder, it would mean a couple of butt splices in the rat's nest of wiring
behind the fuse box, which I'd have a hard time trusting and would also be
easy to lose or forget about.

I came up with an alternative I wanted to socialize and get some opinions
on, and possibly put in my nascent quattro wiring bible.  I've got a couple
of pictures to go explain what I did.

On my car at least, there are four additional fuse holders that snap in
above the main fuse box.  This was always a land of mystery to me in the
past, but I think I've actually figured out most of what's going on there
now.

The top right auxiliary fuse holder on my car only has a single fuse wired
into it, a 16A that fuses the seat heaters.  Since these holders just have
spade terminals on them just like the fan circuit uses, I pulled G1 and G6
(red/black and red/blue respectively) off the back of the 'G' terminals on
the fuse box and put them on the fuse holder terminals, then put the 25A
fuse that was in slot 15 of the fuse box in there.  I tested the basic path
by jumpering my low-speed circuit at the radiator fan switch, and it works.

I figure that at the very least, it's probably easier and cheaper to
replace the auxiliary fuse holder than it would be the fuse box, and it at
least uses the same fuse type and keeps it accessible.

I wanted to see what the list thought of this change and if anybody had any
considerations or problems I hadn't thought of.

Here's a link to a before photo:

http://tropicalboondoggle.smugmug.com/Cars/quattro-wiring/i-BjzsJgf/0/M/DSC2241-M.jpg

And here's an after:

http://tropicalboondoggle.smugmug.com/Cars/quattro-wiring/i-HTwrJVg/0/M/DSC2242-M.jpg

I'll share some of my other notes here as I clean them up and put the
photos together.

Thatcher