Everyone talks about what a nightmare wiring and harness installs are. I presume this is mostly the behind the dash aspect and not the wiring within the engine bay correct?
Correct. Sort of...
Depending on the person experiencing their drama, trauma, trials and tribulations with their wiring, the nightmare may happen anywhere.
let's presume I know nothing, because I know nothing. how hard is it to replace the wiring in and around the engine/ignition/starter/alternator, etc.?
It's the easiest part of the build.
Well, once you get the basics down inside your head that is. Once that occurs, it's all pretty straightforward.
The problem (or one of them) is that most people get intimidated right away and once that happens, wiring is all Greek, Cyrillic and Latin rolled together and taught by their most hated teacher from childhood. I don't really know what that feels like, because I loved all of my teachers until High School. And I even liked the ones personally that I did not learn much from. But I was lucky that way...
So the key is just to figure out what does what and when, then dig in while we look over your shoulder from here.
What happened: I could not get a start the other day, it did turn over and start via a jump. I tested the battery at a parts store and the battery seems to be fine but their tester suggested that my alternator was not getting a solid current. the Alternator is about 5 years old so its unlikely its kaput but the wiring could be. It's some OEM from '76, some OP, some things I have had done (nothing crazy, new light harness, kill switch mod).
Sure, lots of them!
Does the engine start right now? Do you have a volt-meter? Not just a test light, but an actual meter?
If so, start the engine and measure battery voltage at the battery terminals. If it's less than 13v then there is something wrong with the charging system. If it's over 14v however, your alternator and regulator and their associated wires are just fine. At least mostly.
You could also have a slow drain. Or a fast one.
When you try to start it the next time, if the starter won't crank, check battery voltage again. If it cranks normally but won't start, then it's not the battery.
If the battery goes dead overnight while sitting, it can be several things.
1. A failing battery.
2. A drain such as a light bulb not going out. Broncos don't have many of these (or any), but it can still happen.
3. A short somwhere in the system that is keeping the charging system in it's "ON" mode.
4. A failing alternator that might charge just fine, but drains the battery in just a few hours.
5. Probably other things too, but those are the usual suspects.
If it does not die from sitting, but does not charge, then we'll have to test a few other things.
With the battery still connected and the regulator still bolted to the body (you do have a standard alternator setup, correct?) disconnect the regulator's connector and measure voltage at the Yellow wire in the "A" position. Should read full battery voltage all the time.
Turn the key ON (not ACC) and measure for voltage at the Green w/red wire. Should be close to battery voltage only with the key in the ON position.
So those are a few starting points to narrow down where the problem lies.
We can get into the whole "re-wire the engine compartment" thing later.
Paul
