OT - Ford F150 electric windows not working

This is off topic for this Hyundai group, but the relevant Ford Usenet
groups have little activity, so I thought I'd try posting it here in case
there are some generic answers that tend to apply to all vehicles:

This is for a friend of mine. He has a 1997 F150 4WD XLT pickup truck with
a 4.6L engine.

The problem he is having is that both electric windows stopped working at
the same time.

Here is some additional information in case it helps. Before this happened,
he was having a problem with the overhead light in the cab. To get the
light to come on, he would need to push up on the ceiling near the light, so
obviously there was some type of loose connection there. Now, I'm pretty
sure he said that neither the electric windows nor the overhead light work
at all.

He did try checking and replacing/bypassing all of the fuses but that didn't
work.

Shortly before the electric windows stopped working, he had to replace the
entire rear differential and axle. After that, everything was working. But
about a day later he heard a noise in the universal joint and he had to drop
the entire drive shaft and replace the rear universal joint. Immediately
after putting the drive shaft and universal back together, the electric
windows stopped working. I don't see how those two things could be related,
but that is the sequence of events.

He has the door panels off, and he was able to get some print-outs of the
wiring diagram and what looks like the locations for various relays,
switches, and a "GED"(?) or "GEM"(?) controller.

Now, after all of that explanation and background, here are the questions:

Ordinarily, how hard would something like this be for an experienced repair
shop to diagnose and locate where the problem may be located and determine
what need to be replaced or done to fix this? I know that electrical
problems can be difficult to locate, but is there a fairly simple process
that a shop can go through to locate the exact source of the problem the
works in MOST cases? He doesn't have much money, so he can't afford to pay
for hours and hours of time trying to locate the problem.

Or, are there some things that he could do or check or try on his own to try
to isolate where the problem is? For example, if he can find where some of
the relays are located, can he try doing some type of jumper across each one
to check to see if that solves the problem?

He could also go to a junk yard and remove and buy various relays, switches,
and the GED/GEM? etc., if that might be worth trying.

Thanks for any ideas or suggestions.

 

My free advice, which is worth exactly that, is;

1. Try to get a wiring diagram to see if the windows and light are on
the same circuit. My guess is they are not.

2. My guess, if both windows are inoperable, is that it is most likely
a ground issue if fuses/relays check out ok.

3. Replacing the universal is probably (99.9%) unrelated.

4. A repair shop specializing in electrics would be the best option for
service if it is beyond you/your friends abilities.

 

Thanks. I'll pass on what you suggested. I don't think he thought about
the ground issue as a possibility. I know I didn't.

 

Very strong possibility, especially since the dome light worked by pushing
on the headliner

Maybe not directly. If something was marginal, like a connector or ground,
jacking the chassis could have indirectly caused a problem by breaking a
wire, dislodging a connector or something like that.


Another possibility after seeing some automotive engineering is the power
windows work by a belt drive system to the driveshaft for power. I'd write
to Rube Goldberg and ask.

 

Somehow, I don't think Rube will be replying.

The typical method for diagnostics for this sort of problem is to
start at the master switch (and other switch if appropriate). From
there, you can see what power (and ground) are present at the switch,
and what is transmitted from the switch to the window motor. If the
driver's door panel is off, it's then also a simple matter to see what
actually reaches the window motor.

That being said, I know that there has been a problem in some F-series
with the wires breaking in the loom between the door and body. If you
know there's a certain wire which has power (or ground) at one end but
not the other, simply tug on it and see if it pulls out of the loom.

 

Thanks. Very interesting.

My friend has the door panels off and we both just spent a little time this
morning trying to sort things out. I brought a 12 volt test light and a
battery-powered continuity checker with me.

We unplugged that electric windows master switch and used the test light to
see if power was getting to the switch. We checked all of the wires going
into the switch and no power shows up on any of them. Other switches, such
as the electric doors locks, show one wire with power coming in -- but there
is no power to the electric windows master switch.

With the test light, we were also able to check all of the fuses in the main
fuse block under the hood, and all of the fuses showed power on both sides
of the fuse with the fuse in place. We also took each fuse out and there is
power to one side of each fuse connection socket.

At the same time, we realized that there are relays in the main fuse block
and in a secondary block next to that. Since there were multiple relays of
the same type (two different types overall), we tried switching relays
around in case one of them was bad and hoping that by replacing a bad one
with a good one, the problem would be fixed. But that didn't do anything.

So, I'm guessing that means the relays are okay and the fuses are okay, and
that the problem may be that there is a broken power wire somewhere between
the fuse block and relay area and the master electric windows switch. We
had to stop for a while, so that is where we left things for now.

My friend says that he has a wiring diagram that should show him which wire
at the master switch is supposed to have power. Then we can try to figure
out where the other end of the same color-coded wire is in or around the
fuse block and relay area. If we can find that, maybe we can use the
continuity checker to see if there is continuity from one end to the other
or if the wire is broken somewhere along the way.

I wasn't sure how to go about checking for grounds or how to know which wire
at the switch is supposed to be the the ground wire. But I guess that if
there is no power to the switch, it is probably not a ground issue.

 

If you can determine the live wire position to the master switch it may
be easier to just run a new power wire, temporarily, to see if it is the
main power. Easier then trying to trace it back to the fuse block I
would think.

 

Thanks. That's what we ended up doing. We found the live wire postion to
the master switch and then temporarily connected a new power wire to it.
That made everything work.

Now the plan is to figure out running a new/replacement power wire to the
master switch. If we can find where it begins at the fuse box, we can
replace the wire and have it run off of the original fuse. If not, we may
have to run a new wire from a main poswer source and put an in-line fuse in
that wire.


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PRIOR POSTS:

 

Since you've identified the wire, also remove the kick panel trim (or
whatever else is blocking the vehicle end of the harness) and pull the
broken wire through to the inside of the cab. Solder on a new length
of wire, feed back through the loom, and solder again on the section
inside the door. Ideally, you'll want one solder joint inside the cab
and the other inside the door. If the solder joint is in the flexible
loom, it'll tend to lead to premature breakage in the area of the
joint since the joint doesn't flex.