6.0 glow plug harness-- no fusible link?

[The_Josh_Bear]

Here's the diagram for your 89 original wiring. If you look in the upper right corner, you can see where all the fusible links are located, right at the starter relay on the fender. The diagram doesn't show the actual links, but makes a reference to where they are located. The diagram shows the two glowplug feed wires as "black/orange" and you will find those same two at the bottom of the diagram feeding the glowplug controller. But as we all know, these wires are usually yellow also.

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89 truck wiring 1 by D Franklin, on Flickr

Thank you for the details and wiring diagram. I found out last night by digging around exactly that. I'm pretty sure one of the fuse links is cracked inside so I've cut that out and moved it over to fuse things a-la @hacked89 suggested.
Those two Black/orange stripe wires go into the 10-ish-pin plug under the HVAC blower and come out yellow on the other side. They are usually all melty and I bypassed the connector long ago to clean it up for better amperage.

I still find it strange that these power wires are bare under the loom like that but whatevs, Ford had wiring issues for sure.

The only reason I was expecting fusible link to be in the harness was that *I thought* Wes talked about it a bunch a few years ago. Maybe I read it wrong or remember it wrong.

 

[The_Josh_Bear]

Well I ended up putting it on the passenger side anyway since the wiring harness comes through that way. Had to figure out a few things, break some stuff, fix some stuff, re-wire a bunch of stuff-- but I got her glowing now!



I ran the 6.0 harnesses so the pigtails went to the front, over the IP housing cover. I tied them into the old harness there, and loomed it up. Hopefully I won't need to change the harnesses anytime soon but if I do this will make it way easier in the future. Gotta keep those wires away from the turbo heat, too.

Strangely enough I'd plugged in the White Rodgers relay 2 weeks or so ago, and it worked fine...twice. Then it would click but no glow plugs. I had voltage to the plugs but no amp draw. Turns out 7 of eight were burned out, when I've never burned up more than 2 plugs in over 15 years owning this rig.
I had just tested all 8 when I put in the new relay, using an amp clamp so I know for sure they were working. What the heck?

Oh and the best part, as I'm closing the hood when finally done with all this in 40° weather outside today and almost freezing last night, I hear a strange noise and pop the hood again. FORGOT TO CLEARANCE THE HOOD HINGE. I thought it was clear but didn't double-check. Blew up my 250A fuse and didn't even get to test it. Ether to the rescue!

Thanks to @hacked89 again since I was able to turn it upside-down like you did using the same mounting holes and it's safer that way plus easy clearance.

 

[The_Josh_Bear]

Oh and another tidbit, I put my amp clamp on a single GP wire and hit the button-- 44amp spike! Of course it drops to 22amps inside of 2 seconds but that's wild. X8 plugs= 352A inrush current!

 

[captain720]

Do you think the white rodgers relay is cooking plugs? I’m about to install one.

 

[chillman88]

Do you think the white rodgers relay is cooking plugs? I’m about to install one.

No way it could really, unless it failed in the on position. A relay is just a switch. Relays seem to fail "off" far more often.

 

[typ4]

Keep an eye on that cheap 60 harness it will fail eventually. If you want a good replacement glow plug harness this is where you go. I helped him design this for quality and longevity with the proper wire and connectors.

Home | IDI Diesel

Ididiesel.com your source for quality 6.9 and 7.3 idi parts.

www.ididiesel.com

 

[The_Josh_Bear]

Do you think the white rodgers relay is cooking plugs? I’m about to install one.

It's not the relay's fault. I'm guessing the plugs were hanging on because of the low inrush current of the Ford relay. So then use the big monster a few times and they poop out... just a theory. But hooking plugs straight up to the battery in my garage has never killed any, which would be a similar deal. So while I don't know why they died, I can say it's not the relay's fault just due to the nature of electricity and what these things do.

The WR relay is pretty stinking cool though. It's kinda loud when you hit the button and if you pop the hood it makes a cool sound like vibrating metal. It's the sound of big time amps pumping through!

Keep an eye on that cheap 60 harness it will fail eventually. If you want a good replacement glow plug harness this is where you go. I helped him design this for quality and longevity with the proper wire and connectors.

Home | IDI Diesel

Ididiesel.com your source for quality 6.9 and 7.3 idi parts.

www.ididiesel.com

Thanks Russ, I would have gone there if I'd known!

 

[The_Josh_Bear]

No way it could really, unless it failed in the on position. A relay is just a switch. Relays seem to fail "off" far more often.

Agreed. And they'd BETTER fail off!