This is where I am at right now. I pulled the fuse box best I could. There are
no burned wires that are visible. There are no burned fuses. Everything in
the truck works (accept the wipers) and of course it will not start. I see no
burned wires from the ignition switch. So, the only thing I can see not
working is the fuel pump. I also replaced the fuel pump relay because I had a
spare and thought that might be it. There is no car alarm on the Bronco. I will
take a jumper wire and see if I get any codes.
So, check engine light does not come on, and I cannot pull any codes. I
jumped the fuel pump and it works fine. Not sure if it is a no no, but I left the
fuel pump run on the jumper and tried to start the truck, but still would not
start. So, now I know it is not a fuel problem, other than the pump not
pressuring up when turned on. I am no expert, but I am thinking ignition or
fusible link? I have not been able to locate a fusible link yet though?
You are kicking serious electrical butt! ...you just don't know it. ;)
Keep going, the trouble is right there waiting to be found because it hasn't
gone and cleared itself up on you. That's your only "fear" at this point, that
the trouble will clear up before you find the problem. BTDT a jillion times. :)
The meter will lead you right-to-the-trouble if you "let it".
That's all you need to learn about electrical troubleshooting is -how- to let
the meter find the trouble. This hands-on-trouble you got going right now
will do that for you.
Wiring diagrams, a volt/ohm meter and the willingness to "stand on your
head" when needed is all you need to make it happen.
Steve's idea to read resistances (ohms) on a bunch of crazy-ass stuff is
genius! :) Do some of that, get a feel for it.
Read the Bronco's battery voltage.
That one is trickier in that it takes more explanation is all. Not sure at what
point you're gonna need to use that one today (or not) but it's an important
one for future electrical troubleshooting.
While the wiper switch is "on" (wipers working or not) you read the voltage
(any voltage) across the contacts of the wiper switch. Any voltage reading
you get is the -voltage drop-.
Zero to full battery voltage is possible.
Zero volts is best of course, if the wipers are moving back and forth. ;)
-short- and -open-
If you were to get "full battery voltage" across the contacts then the
contacts aren't making good, they are -open-. The rest of the circuit is
less-resistant than the contacts. In-theory the rest of the circuit is fine.
Fix the switch's contact problem (or bridge it with a wire) to test the
"theory". If it still don't work (and the wire ain't getting hot as heck;)
continue on reading voltage drops.
That's one way to do it, another is to use the ohmmeter hooked in series
with the circuit.
A -short- circuit is the sort of thing that makes wires smell like they're
burning. An -open- circuit is like when you turn a wiper switch off. The
circuit is -open-. But also if the contact inside the switch is bad or a loose
wire that keeps the circuit from working. If that loose wire were to touch
something it could cause a -short- circuit and burn some wires up. :/
-series- and -parallel-
When you read the voltage on the battery the voltmeter is in -parallel-.
If you >disconnect< the battery cable and put one meter lead on the
terminal and the other on the cable clamp the meter is in -series-.
Typically you use ampmeters (with the circuit energized) and ohmmeters
(with the circuit de!-energized) in series.
Wiring and hunting down wiring problems "hurts" sometimes. :)
Reaching into places that wasn't meant to be reached into by your fingers,
hand, arm, shoulder, chest, waist, hips while standing on something rickety
or hooks jammed into a pole or in this case upside down "standing on your
head" while working under a car-dash (or relay house at work).
A couple guys at work would have made good wiremen but they were just
too short and stubby. LOL :)
Alvin in AZ