Skiddplate

Ok, new guy here, greetings from the Kingdom of Nye. I searched the threads here and found a couple of people with the identical symptoms, but, unfortunately none of their fixes worked for me yet.
Truck drives down road, suddenly loses all engine electrical, dies, all dc gauges dead, lights and windows still have power. Fuses good. Fuse links and bulbous connector plug intact and showing power on both sides.
Disconnected plug with brown and pink wires, jumpered, motor cranks but no fire. No voltage at FSS. Replaced ignition cylinder and ignition switch.
Nuthin'...I've hit the wall here. Mayday!

BigIron70

If I remember right it has been a while since I worked on a 1ST gen but some things I do remember is the wiring harness would always rub on the brake booster and short out, the wires to the fuel heater and run solenoid are in that harness. Also check the fuel heater wiring, if the fuel heater is loose it will spin slightly when removing the fuel filter and cause the wires to the fuel heater to short out. This is all I could find for 1989 CTD might be some help. Trucks were so much simpler back then.

taterfarm

List out what does and doesn't work in the cab. Radio, fan, gauges, ext. If you need to run the truck short term then just run a jumper to the fss from the battery. Try checking the relays on the fender too, I had a poor connection there once that had me on the side of the road for a bit. Seems like the same items where dead, fan and radio but windows worked. Try wiggling the wire harness all around the fuse links and relays to see its a poor connection, have the key on someone watching to see if you get power in the cab.

Skiddplate

no gauges, no radio.
windows, fan, dome light work. What are the two small coil looking things mounted in tandem on the left inner fender area? Each one has two terminal posts with heavy gage cables connected.

Skiddplate

I was thinking the coil looking things were for the plug heaters. What exactly do the relays look like on that year? As far as I know, the truck is stock except for the cooler. And I surely appreciate the help guys.

KRB

Have you checked the orange wire fusible link coming out of the duck foot on the driver's fender specifically? I think that one powers the gauges and radio too if I remember correctly?

Yes, they are for the grid heaters.

taterfarm

It was about six years ago when this happened to me so i had to go out and look it all over again to remember what it was. the end of the fuse link was bad so moving the harness around would make connection, the relay would click on and off when it made connection thats why I was thinking relay. Anyways, I think hes right on the orange fuse link, think its the inside one, it connects to a pink with black stripe wire in the harness, that needs power for radio, gauges and start.

Here is a link from the sticky to replace all the fuse links with a fuse block, I did and just went out and pulled the fuse from the pink/black wire, then the radio and gauges quit and it wouldn't start. Get fused power there and you should be good unless its shorted in the middle.

Fuse link removal:https://www.dieseltruckresource.com/...t-t135504.html

list of what all the electric things are under the hood: https://www.dieseltruckresource.com/...d.php?t=128911


good luck.

Skiddplate

Looking at the pics of underhood electrical items I see my truck does not have the 3 multi-use relay blocks like the ones on the fender in the pic.
I located the duckfoot with an orange wire coming out of it to a square plug connector and a black wire coming out the other side of the plug and going back into the harness. With the key off, test light shows power on firewall side of connection (black). With key on I have juice on both sides of plug. (orange & black wire.) Incidentally while the key was on I was pulling and wiggling the wires coming out of the broadside of the duckfoot and one of the black wires coming out of the harness alongside the duckfoot suddenly crackled and started cooking off like a cannon fuse. I quickly turned the key off. 4" of wire vaporised. I thought the fusible links were those inline cylindrical bulges on the heavy wires coming off the battery into the harness. Was that length of wire a fusible link itself and did it just partially blow when my truck died and now it finished cooking off when I grabbed the wire under power?

Skiddplate

Ok. Examining the charred remains of the wire, I make out bits of letters, that say-wait for it- fusible link.. I'm reaaaally hoping this thing only partially blew at first and this was the lurking culprit. Guess Ill go find some terms and a fuse block now. Geez, good thing I tore my steering apart and replaced igniton switch. At this rate I will be a bona fidey 1989 D350 expert in no time.

Skiddplate

put a jumper where the FL blew. turned key on, and smoke started coming off the wire at the FSS. Im thinking the FSS power wire chafed through on a bracket next to where it connects. Now I'm cutting the burnt wire out of the bundle almost all the way to the fire wall. This sheeit is fun.

taterfarm

sorry, wrong year truck. here is a new link for what you have on the older trucks:
https://www.dieseltruckresource.com/...d.php?t=130793

fuse links seem to burn up in strange patterns, sometimes its just inside and the outside is fine then there is what you watched and its gone. It wasn't anything you did anyways, might as well clean it all up and have some room to add some new fuse connections if you need them.

When I replced mine I bolted in a sheet of diamond plate on top of the fender and put a blue sea covered fuse block in, eventually I'll add a second one too.
here is a link to the the blue sea block, there are many other types and brands but i like these with the cover and screw connections rather than tabs, that and they have ground terminals too as these trucks always seem to have grounding issues: http://www.bluesea.com/products/5025..._Bus_and_Cover

taterfarm

add an inline fuse to that instead, you don't want the truck burning down.

fuseable links are made to burn up like a fuse would pop, you dont want to replace them with just wire.

KRB

I've read that fusible links are different than fuses. Granted many of us have replaced them with fuses and all is well but there at one time was a reason for the link and not a fuse. Not sure what the difference is though...

Skiddplate

Thanks guys. I only clipped a jumper between the 2 wires to see if it would fire. That's when I saw the wire going to the FSS puff a smoke signal. yup, we got fire... Key off, and I find the FSS wire chafed thru while riding a small bracket on the block. TA-DAA! BingoBango! I unwrapped the harness, and cut the roasted FSS lead out back towards the F/W and spliced in a new 12g conductor. Also spliced in a fuse block with 30A blades where the fuse links loiter. She, of course, fired right up.

KRB

Glad you found it!