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Not So Ur q Questions
In message <199612020809.DAA24190@hammurabi.nh.ultra.net> human writes:
> I liked the underhood fuse box on my 83 5kt, you could get to both sides
> of it to work and you didn't have to kneel in the slush to look at it on
> the roadside.
Get yourself an urq. You get both.
> I will, however, definitely be upgrading the lousy 8 (if that!)
> gauge wires between the alternator, the fuse panel, and the battery, to
> something more substantial. The main reason for observed voltage
> fluctuations at the console voltmeter in my car is series resistance, not
> operating voltage. My 100 watt high beams running off the alternator prove
> that. Hmmm, the rear window defroster is also another major candidate for
> rewiring, both +12 and ground. Turning it on trashes my radio reception!
Series resistance also defeats the capacitor installed to suppress interference
from the alternator. It's not uncommon to find resistances becoming higher in
old auto wiring, partly because the grain structure in the cable changes slowly
over time. Copper wire is hard when first drawn down to size, and is annealed
to soften it for "flexible" applications like auto wiring. This process also
reduces its electrical resistance. Over time, carrying current, the annealing
process reverses. If the wiring gets hot frequently (often the case in Audis)
the process is accelerated.
I find _many_ of the circuits on my urq are under-specified. Especially the
rear wiper, which is fused for 25 amps and can pull 15 amps when stalled (e.g.,
with the blade frozen to the screen) but is wired with 1mm wire.
(As an aside - always make sure the wipers park properly in winter. If they
freeze in the parked position, trying to start them obviously fails and you
then go and free them. The motor is only pulsed by your attempt, but the
stall current is switched off when you switch off the wipers. If they're
frozen but _not_ in the parked position, the motor itself contains a parking
switch that will keep current flowing all the while the ignition is switched
on. The motor and wiring can get mighty warm while you're walking round the
Committee Member, UK Audi [ur-]quattro Owners Club