> Consequently, I am considering the purchase of a wiring harness.
> However, before taking such a money- and labor-intensive plunge, I
> request the advice of those who have had any experience with such a
> project.
>
> In deference to Jim's request that we minimize our traffic on the
> list, feel free to e-mail me directly. Of course, I'll keep everyone
> apprised of the situation.
>
I was going E-Mail this directly, but since I haven't seen the subject
mentioned here before, I thought the response might be of general
interest, so I'm posting it to the list (boy, things are getting bad
if a SOLer has to feel guilty about posting something to the list. I
remember when ovr founder was soliciting descriptions of our respective
cars in an attempt to drum up some traffic).
My advice to you as far as replacing the wiring harness is to avoid it like
the plague. I've replaced a couple of wiring harnesses and the job is no
fun at all, and at least in my case, both harnesses didn't quite match the
dimensions of the original (a lot of the branches were simply too long),
and there were extra or missing parts from the harness. The length problem
was undoubtedly in there on purpose, in the theory that its better for it
to be too long than too short, but the extra and missing connections were
a bit of a mystery, because the cars that I did this on (XK-120's) are
very simple cars with few (if any) electrically operated options. The
more modern the car, the more different versions of the wiring I would
expect to exist, multiplying the chances that something won't be correct.
I've done a lot of electrical work on cars, and it seems like the best thing
to do is to look at the harness that is in the car, and try to figure out how
it was originally routed, and where connections were originally made. You
pull out all extraneous wires that were tacked in over the years, feed the
wiring harness through the original routing, and look over the situation.
In most cases, removing old jumper wires and reconnecting original wiring
will be possible and will work (of course you have to troubleshoot the original
problem, but that was undoubtedly a bad connector under the dash or a bad
switch or whatever; its extremely rare for it to be a bad wire in the
harness). In severe cases you may wish to replace a section of the harness
with a good used section of harness. This might be appropriate for an
engine compartment whose harness was badly botched, for instance. The best
way to do this is to cut off the harness in an easily accessible spot that
is before the damaged section (such as near the firewall for our engine
compartment example). Then strip both your replacement harness (which you've
already checked matches your original harness down to wire colours) and the
stub of the original harness. Slip some heat shrink tubing over each wire,
and solder the wires from the new harness section to the stub sticking out of
the firewall, slip the heat shrink tubing back over the soldered section,
and heat the heat shrink. After doing that to all the wires, you can wrap
a couple feet section of the harness in black electrical tape in a spiral
pattern, which makes it look like it came from the factory that way, if
done right. Then feed the new harness through, letting wires end up sitting
next to where they will eventually be connected. The final connections are
easy because when you removed the old harness section, instead of disconnecting
it from everything, you simply cut it near the end of each branch, leaving
a little section of harness dangling off of each electrical component. You
then have an easy way to match colors.
If you insist on replacing the wiring harness, make sure to use the same trick,
don't disconnect anything, instead just cut off the end of each branch of the
original harness. You'll save yourself an incredible amount of hassle.
Joe
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