What would melt this wire

[tequilaiam]

The one connecting the negative terminal of batt. 2 and the engine wiring harness block (above the GP relay)?

P.O. had a stuck starter relay but I don't see where that would push current through this wire. Its not 12V converted.

I know he replaced glowplugs, is it possible he wired them to 12V?

THe melted one is highlighted here:

 

[K9Vic]

It is likely that the wire was overloaded with too much amperage to handle the wire gauge. This is 12v power supply for the truck 12v system and added accessories. The wire should have a fusible link and not have melted as you described.

Hooking up 12v to the glow plugs would give you 6v when they are on and your truck would not start.

 

[overkill375]

has the wiring been screwed with or modded in any other ways?

 

[Pawnshop]

I can tell you from first hand experience that if your starter is running away due to a bad relay or solenoid and you disconnect the neg lead from the FRONT battery ONLY you can get 12v to feed back to the starter and it will continue to crank slowly, and while you are frantically trying to remove the neg from the back battery the fusable link and other wiring insulation will burn in the area shown in K9Vic's photo above. Lots of magic blue smoke will escape and your truck will stink for days...

 

[doghead]

Hooking up 12v to the glow plugs would give you 6v when they are on and your truck would not start.

That's only correct if, you resupplied the resistor bank with 12v.

If you eliminate the resistor bank and resupply the GP relay with 12v, all GPs will get 12v(even after one or more fails). This is a fairly common modification I recommend.

 

[K9Vic]

Hooking up 12v to the glow plugs would give you 6v when they are on and your truck would not start.

That's only correct if, you resupplied the resistor bank with 12v.

If you eliminate the resistor bank and resupply the GP relay with 12v, all GPs will get 12v(even after one or more fails). This is a fairly common modification I recommend.

Yes I was referring to using the resistor block hooking up 12v incorrectly. All my trucks have the resistor bypassed except my M1010 that was converted to 12v.

 

[Ghost2012]

It is likely that the wire was overloaded with too much amperage to handle the wire gauge. This is 12v power supply for the truck 12v system and added accessories. The wire should have a fusible link and not have melted as you described.

Hooking up 12v to the glow plugs would give you 6v when they are on and your truck would not start.

Even if your glow plugs are dead/low voltage, the truck will still crank...

I only know because I've cranked the truck by accident with the glow plugs disconnected. It runs like **** but it runs...

 

[Pawnshop]

Some of my glow plugs in the M1009 are bad and when it's real cold out the truck will start and run bad for a few moments, passing light gray smoke and making a "wop wop wop" sound till all of the cylinders even out and then it runs fine. If all the glow plugs were bad I doubt it would start at all.

 

[tequilaiam]

has the wiring been screwed with or modded in any other ways?

Yup. I took a closer look and the resistor pack is gone with the GP relay connected to the 12V block in the picture. The wire looks like it was from radioshack, 10 or 8 gauge but I didn't see anything that looked like a fusable link...must have gone out with the conversion.

What pawnshop described is probably what happened, the neg. terminal on the front battery is chewed up.

pawnshop, what smoked in your circumstance? I'm wondering if my GP card is fried too since the WTS light stays on about 10 seconds and another 5 until I can hear the relay start to flutter (or is that a buzzer?). When it does fire up, its rough at first and there's white smoke from the tail. So a few GPs are likely dead from staying on the max time.

PO said he replaced the GPs and card already thinking that was causing his starting issue. Guess Ill check that next


In the mean time, what's the recommended replacement for a fuseable link? A regular slow-blow fuse? What current?

1.5 ohms is what I should check for in the glowplugs, correct?

 

[Pawnshop]

Some insulation came off but the only true loss was the fuseable link to the glow plug relay, burnt right up. I have it bypassed right now with some wire but I need to fix it correctly. I have wondered the same, would an inline fuse holder do the job?

 

[tequilaiam]

Some insulation came off but the only true loss was the fuseable link to the glow plug relay, burnt right up. I have it bypassed right now with some wire but I need to fix it correctly. I have wondered the same, would an inline fuse holder do the job?

I read on CUCV electric's site that a fuseable link is a section of wire 4 gauge sizes above what you're trying to fuse. So a 8 ga. wire would use a small section of 12ga spliced in.

CUCV Electric

Thats pretty easy! Its probably in a TM somewhere but over 1000 pages is a lot to look through!

 

[doghead]

Thats pretty easy! Its probably in a TM somewhere but over 1000 pages is a lot to look through!

No kidding, what if you read all that and actually learned something....

 

[Recovry4x4]

I read on CUCV electric's site that a fuseable link is a section of wire 4 gauge sizes above what you're trying to fuse. So a 8 ga. wire would use a small section of 12ga spliced in.

CUCV Electric

Thats pretty easy! Its probably in a TM somewhere but over 1000 pages is a lot to look through!

I'd start in the electrical section. Sneak up on all the rest.

 

[gearcc]

Hooking up 12v to the glow plugs would give you 6v when they are on and your truck would not start. gear wheel

 

[gijoe13]

Well my truck with 12v runs fine. You bypass the resistor bank to supply 12v.

 

[K9Vic]

Gezzzzzz talk about not being 100% detailed in my comments.
When I said if you hook up to 12v you will get 6v, of COURSE I meant not going through the resistor block. That would be the only way for that to happen as the resistor block was designed to drop the voltage in 1/2. All my trucks are bypassed so I do not fry my new set of GPs.

 

[semocoachworks]

Some insulation came off but the only true loss was the fuseable link to the glow plug relay, burnt right up. I have it bypassed right now with some wire but I need to fix it correctly. I have wondered the same, would an inline fuse holder do the job?

Napa sells actual fusible link wire. I had the same issue with my 09 and this worked well. Give me a few minutes and I'll run out and get a part number for you.

 

[semocoachworks]

786542 I believe is the fusible link wire I used on mine. It's napa/belden brand. I have had no issues since I put it on.

 

[BenderIsGreat]

Old thread but I think I found a new way to melt that line. If your passenger alternator swings inboard too far (while adjusting belts for example) and the rubber boot gets pinched/pushed out of the way, the innermost threaded terminal on the alt will touch the fuel lines running by there and cause "excess current" resulting in letting the sparks and smoke out at the point of contact and apparently a lot of smoke at the indicated wire.

My electricals are dead for now and I hope just replacing the damaged section will fix it but for some reason I don't understand, I still get 12v before and after the break. The vehicle was fully off but the batts were still connected. My wiring had a lot of 'improvement' by POs so YMMV.

Hard knocks learned.

-M1009