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I replaced my battery cables on my 2000 F450 7.3L. I did not pay close attention to the starter relay hook up. The original cable has a flat molded end to attach the to the relay that separates the positives one going to the battery and the other going to the starter.
The replacement cables do not have that molded end, and I stupidly put both cables on one terminal and sparks occurred.
Well, I have no power to the cab. No interior lights, no headlights. Nothing.
I checked the fuses in the power distribution box, my interior fuses as well. They all check out. Nothing blown. I even tested for continuity.
I checked my starter relay for power with the key on but, I have nothing showing up on the dash so I'm not really able to test it. No glow plug indicator.
I do not see how putting the starter trigger and the always hot on the same stud could cause a PCM failure.
If you had the starter primary hooked up all that should have happened is the starter spun up.
You may have missed the 2 fuse link wires that run aft towards the cap to a bigger cable to power cab items. May have arched and blown them... Check there.. see finger in photo.
Maybe... if you have the updated harness version towards the end (not sure if the F450 followed the others), check under the air box for the diode. You may or may not have this item in the system.
Fender Starter Relay Diagramm
Thanks for the sketch and the pic.
Sketch indicates factory plug that goes on the relay. Skinny wire goes to the starter on one post and the other hot goes on the other post. I put (touched) the heavier cable to the skinny cable post and wham.
My new cable set did not have that molded end but individual wires. I just wasn't paying attention.
I have top double check also the skinny wire to the starter relay is on the correct post. Based on your sketch, I have it reversed but I was certain I checked its location from the old harness.
Did some more research and seems to be either one or both of the fusible links. I can't seem to find a pic that shows the details of it. It comes off a 12gauge wire and splits to (2) gray wires (as your pic shows)
There are (2) sets. One powers the power distribution box which essentially powers everything in the cab via fuse panel in the cab.
I'm guessing the fuse is under the eyelet??? Molded in?? I'm also searching the part to no avail. I guess I'll got the dealer.
Yes, I know the gray wire(s) are the fusible links. I just can't find aftermarket part or any part number for them.
I bought my cables from Custom Battery Cables. The hook up to the relay is not like the original molded plug. Instead, individual cables.
I'm trying to also confirm whether the skinny starter relay wire goes on the post towards the truck front or on the firewall side.
The PCM is protected from accidental connection of +12V to a GND connection. The diode will not let 12V reverse flow through the PCM by turning off power to the PCM through the PCM relay. Hopefully your is OK.
Thank you Don Ridley. I agree. PCM probably ok
I did confirm starter relay wire is on the post closest to the front of the truck just like Jimmy's Pilot Service showed in his sketch.
The other post is the constant HOT and the (2) fusible links.
Still can't find a Ford part number for those fusible links. I think they are the culprit and shorted when I made the wrong connection.
I would really like to know how they work and what the fuse looks like in the rubber jacket.
I researched fusible links some time ago. You can buy a spool (or shorter sections) of fusible link wire if you know the gauge or current rating. I remember the links are color coded for their current rating. I would go salvage some from Pick N Pull. Many Ford truck will have the same size links.
Fusible links work by melting and opening the circuit without causing a fire. They look like a piece of wire.
12 gauge is what is says on the jacket. I don't know the current rating though. Wires are gray in color.
I'm just curious as to how it works. Thank you
I'm a pool contractor for over 40 years and pool heaters have fusible links. They activate when too much heat is in the cabinet. A little part that looks like a resistor is filled with wax mounted in the cabinet. When it melts, power is cut to the heater. Prevents fires.
