electrical wiring at relay question (1 Viewer)

[runningdaddy]

While checking a few things in the engine compartment this weekend, I noticed the previous owner did some interesting mods on the wiring harness near the positive terminal of the battery. Please look closely at the blue (slightly burned) wire connector near the relays.

I'm really interested to hear ideas on if this is an issue or how I can repair.

 

[1911]

Can't tell from the photo if it's a bit of heat-shrink tubing that didn't get fully shrunk, or a cheap-ass crimp butt splice that didn't get fully crimped. He used cheap-ass crimp terminals on the battery wires and did an amateurish job of it.

The bigger question is, why does he have two fuses in series (in line) on that single wire?

 

[runningdaddy]

Can't tell from the photo if it's a bit of heat-shrink tubing that didn't get fully shrunk, or a cheap-ass crimp butt splice that didn't get fully crimped. He used cheap-ass crimp terminals on the battery wires and did an amateurish job of it.

The bigger question is, why does he have two fuses in series (in line) on that single wire?

It's a crimp splice that wasn't well done. I don't know if I should try to solder in additional wire or if I could remove a few relays and cleanup the wiring harness.

 

[Walkerm916]

I vote to clean up the wiring you will be happier with it in the long run. I know the feeling I have random wire dangling behind my dash that aren't connected to anything.

 

[SouthMS40]

You've got the battery, fuse holder, blue splice, another fuse holder/connection with a heavy gauge white wire with blue stripe coming out of the bottom. If I remember correctly, that wire is your supply to the fuse block in the cab. If this is correct, the cheap undersized splice cannot carry the required amp draw and is heating up. My 40 caught fire due to a prior owner's wiring hack job so I'd HIGHLY suggest figuring this out!!! At least be sure you have a fire extinguisher. Quick release battery connections are a good addition too.

 

[runningdaddy]

You've got the battery, fuse holder, blue splice, another fuse holder/connection with a heavy gauge white wire with blue stripe coming out of the bottom. If I remember correctly, that wire is your supply to the fuse block in the cab. If this is correct, the cheap undersized splice cannot carry the required amp draw and is heating up. My 40 caught fire due to a prior owner's wiring hack job so I'd HIGHLY suggest figuring this out!!! At least be sure you have a fire extinguisher. Quick release battery connections are a good addition too.

I took some time and figured out I could bypass the first relay and hook it straight into the second relay (just past the blue splice). This allowed the heavy gauge wire to go from the battery directly to the second relay and remove the black/red stripe wire and white/blue line/red stripe wire.
Everything fired up and lights are working. I noticed the small black box (bottom left in the pics), has these two (bypassed) wire colors in it with spots for fuses. Of course, there are no fuses and everything is working.

As most drive way mechanics, I ran out of time and light and will return another day to check into this further.

I am still open to suggestions on how to proceed.

 

[1911]

Just FYI, those are fuse holders, not relays.

 

[Solace in Solitude]

As Lee said, those are fuse holders.

I can't tell what wire colors they are spliced into... But, I suspect the wire that had the two fuse holders, in series, was/is a homemade fusible link...

A fusible link would run from your battery pos (+) to the white-blue wire, in your harness on the passenger fender... You can see it in this picture... Left side, halfway down. Your full wiring diagram can be found here Coolerman's Electrical Schematic and FSM File Retrieval

You really need to clean up that mess and make sure your fusible link is properly sized, before you burn your wiring harness and possibly your 40 down.

I melted my harness, I'd hate to see you do the same.

If you need a real fusible link, contact @Coolerman, he sells everything you need.

Also, from the little I can see of your positive battery terminal, you really need a new positive cable... The connection to the positive terminal is barely there and the cable 'look' like it may be too short and too tightly stretched.

Good luck.

 

[runningdaddy]

So, I reconstructed the wiring harness that was damaged. I had to use some non OEM parts, but think it is working nicely.
Now I'm curious what size of fuse to put in the little black fuse box? 15amp? 20amp?

 

[Solace in Solitude]

That "little black box" is not OEM... Again, I think someone tried to create a fusible link...

As suggested before, I would buy the proper fusible link parts from @Coolerman and clean it up completely.

When the fusible link is present and properly sized for your truck, you have a modicum of security from burning up your harness and, potentially, your truck.