Died & won't start?

[KRB64]

Dad's truck quit on him the other night. Just cut off while going down the road. Won't turn over or anything & some of the electrics don't work. Its a 1993 W250 manual that he's had since it was born and only has a little over 100K. I wasn't up to troubleshooting in the rain and dark so I just towed him home.

I figured it was a fusable link. But I have checked those that come out of that duckfoot thing on the fender and they all seem good. BUT, at the fuse block in the cab I can't get power to fuses 1,2,3 or 7,8,9,10 - even with the key on. I'm pretty sure those have power to the firewall connection - at least the pink with black stripe wire does which I think serves 1,2,3.

I can cross out the starter and get it to spin but it obviously won't catch with the fuel etc not getting juice.

Any ideas? Am I missing a fusable link somewhere? The connection block at the firewall looks like brand new.

[Philip]

There are two smaller black wires coming off the battery. About 6" from the battery is a splice in both of them. Check with a test light and see if both have power on both sides of those splices.

I had problems with one of mine last year.

[Ace]

The ignition switch itself could be gone bad.

[KRB64]

Thanks Philip, I'll check those.

Ace - The ignition switch "feels" the same. Could it just go bad inside and still act the same? I replaced mine this summer but it wouldn't start because the key just kept spinning round & round...

[KRB64]

Well those two FL on the black wires off the battery "appear" to be OK too. Haven't found where they go to see if I have juice on the other end yet.

[cougar]

I believe those fuses at the battery are for the grid heaters. Fuses 1, 2, 3, 7, 8, 9, and 10 go through the ig switch. The ig switch is fed by 2 fusible links.

[dpuckett]

Check the fusible links- they can look and feel good, yet not transfer power.

[KRB64]

I thought I checked both sides of the FLs. I'll find a wiring diagram and trace the wires to make sure I'm looking at the right ones.

[cougar]

I thought I checked both sides of the FLs. I'll find a wiring diagram and trace the wires to make sure I'm looking at the right ones.

One should be pink and black, the other red that feed the switch from the FLs. Both FLs should be orange.

[KRB64]

I know the pink with black stripe was working. I'll double check the other.

Plus somewhere I read about some wires on the block under the fuel filter that get fuel soaked - tape comes off - shorts on block...

Next I guess I'll expose the starter switch and see if thats the culprit.

[KRB64]

I pulled the ignition switch cover. On the wide flat plug going to it, of all the wires, the only one that is hot is the pig pink one with the black stripe.

Is that the way its supposed to be?

[Ace]

What's it look like in there, anything look crispy or warped? Does it warm up when switched on? Any other wires light up after switched on?

If not, you got power in, but no power out which ain't strictly speaking, a "good" thing.

[Mark Nixon]

Fusible links can look and FEEL like they are intact, but more than once I have pulled on the wires and the coating stretches, which indicates the wire inside the link section is burned.
The coatings on the links are generally of a higher heat resistance due to their nature, so they don't tend to burn visibly when a link pops.

Mark.

[KRB64]

The red wire should be hot too. It's hot on my truck so I jumped from the battery to the bulkhead connection and it fired right up. Found the culprit. Now I'll just trace it backwards.

[KRB64]

Turned out to be the orange wire at the end of the duck foot. I thought a fusable link was actually a thing, didn't realize it was the wire itself, thats what threw me off.

I installed an in-line fuse and have run a new 18 ga wire. It started right up and ran. Drove down to the barn & back fine. When I parked and tried to restart it blew the fuse after the first crank or two. Of course I hadn't found the initial short but that red lead goes to practically everything!?

What size fuse should that cicuit have? The manual doesn't rate the fusable links. I had a 20 in there.