Lost some electrical while driving

[turbohaulic]

My little brother bought a 91 7.3 two days ago and was driving home when he lost power to the truck and coasted to a stop. He still has his head lights, hazards, dome light, key beeper, and horn. The key does not do a thing as far as turning anything on or off. I heard the multi-function switch that the key switch rod goes to can go bad so I replaced that but it did nothing to solve the problem. Has anyone heard of a problem similar? Or has any suggestions? I hope I don't have a wild goose chase coming up for any short Thanks a bunch!

 

[79jasper]

Check the plug that goes to the engine harness. I'm not sure if your year is driver or passenger side, but the plug will be near the middle of the valve cover.

Last possibility would be the wiring to and/or the starter solenoid.

 

[turbohaulic]

Nothing is working with the key. He did find a fuse-able link that was toast and is replacing that now. Hopefully thats it. I'll have to check that plug by the valve cover. I don't think it would be the starter solenoid because he was going down the road when it died. Thanks for the replies, I will see if this fuse-able link fixes it.

 

[MIDNIGHT RIDER]

I don't think it would be the starter solenoid because he was going down the road when it died.

I think what was meant when the starter solenoid was named is the fender-mounted starter solenoid/relay is also the main electrical junction point, where all other components tap on for power.

There are several fusible links attached at the solenoid/relay.

 

[turbohaulic]

I think what was meant when the starter solenoid was named is the fender-mounted starter solenoid/relay is also the main electrical junction point, where all other components tap on for power.

There are several fusible links attached at the solenoid/relay.

Good to know It is now up and running again. It turned out to be that fusible link. Thanks everyone for the replies!

 

[79jasper]

I think what was meant when the starter solenoid was named is the fender-mounted starter solenoid/relay is also the main electrical junction point, where all other components tap on for power.

There are several fusible links attached at the solenoid/relay.

That's what I meant, just in less words.

Well good that it's going now.
What was used to replace the link?

Hopefully not just a piece of wire. Obviously it blew the link for a reason, with just a wire most likely you'll be coming back to tell us the truck burned down.

 

[LCAM-01XA]

with just a wire most likely you'll be coming back to tell us the truck burned down.

Not necessarily - everything big-power that link feeds is fused. The only stuff that isn't fused is the ignition circuits and the diesel warning lamps module (water in fuel and wait to start), and those all run on pretty small-gauge wiring - due to the nature of a fusible link (same as a slow blow fuse) if the problem was indeed in the non-fused ignition circuits there would be smoke and stink coming out long before the fusible link popped.

I think the initial issue was the ignition switch, those are known to catch vehicles on fire. He replaced said switch already, so hopefully he should be good. Still, it does not hurt to inspect harnesses for burn damage.

 

[79jasper]

Ah that makes sense.
Just when it comes to elecrical related stuff, I'd rather over emphasize possibilities than to just brush it off.

I'd still put a slow blow fuse in.

 

[MIDNIGHT RIDER]

I very-much prefer circuit-breakers over fuse-links.

The reason O.E.M.s use fuse-links is because they are much cheaper for them, maybe not one-at-a-time like we would have to buy them; but, in bulk, the fuse-links would be way cheaper than breakers and a lot quicker at the assembly-line.

Wiring harnesses are farmed out to little minimum-wage factories in Kentucky and the fuse-links get spliced into the harness as it is manufactured; breakers, on the other hand, would needs be installed and then have each wire attached, after the vehicle was mostly assembled.


Contrary to what many believe, the "engineers" don't design vehicles with your best interests in mind, they design them to shave off every cent of cost they can and the vehicle still work for a short while.

 

[MIDNIGHT RIDER]

I will add that I have seen many many fuse-links deteriorate and fail, or --- worse yet, become intermittent ---from plain old age.

I believe Chrysler and especially the Dodge trucks are the worst offenders for fuse-links self-destructing with no other electrical problem existing.

I have yet to see one blow due to an actual electrical malfunction; I am not at all saying it cannot happen, just that I have never seen it.

 

[79jasper]

I believe Chrysler and especially the Dodge trucks are the worst offenders for fuse-links self-destructing with no other electrical problem existing.

Is that where the main smack talk on dodges(excluding auto trans lol) having faulty wiring comes from?