Headlight, Running Light Help

[rsl0311usmc]

Hey everyone I am having a little issue with my headlights here lately. My fuse is apparently getting hot to the point it's melting but not blowing. I did some research on here and have heard it's commonly over loaded and it could even be the horn fuse which I took out today. There is a tiny bit of melted area we're the fuse plugs in for the headlights. I was considering cutting what looks like a red wire for that spot and putting an inline fuse but I am unsure of what other wire to splice into on the backside. I will take some pictures. I see there is what looks like a red wire that powers it and then directly behind it another red. Any help is really appreciated

 

[Jeepadict]

Cutting random wires for unknown reasons and adding uncalculated circut protection does not sound like a good idea to me. I reccomend a systematic approach to any malfunction, most call it Troubleshooting.

First step in Troubleshooting: duplicate the discrepancy. If it melted a fuse instead of blowing, replace the fuse with a new one, see how long it takes for another one to blow/melt. Once you duplicate the discrepancy, you then have to find the mechanical reason for the discrepancy to exist by essentially cutting the problem in half: basically, what can you do to the system that makes it better vs makes it worse. That truck went somewhere near 4 decades without melting fuses, so something happened to cause it to happen...something either malfunctioned/broke from use or changed behavior due to age/decay.

Are there any modifications made to that part/system in the truck? What were you doing just before the melting happened? Have you been smelling melted plastic for a long time, or did it happen just now? Does it melt when all the lights are on?...just running lights?...all off? More story and background helps us figure out where to look.

My money is on the headlight switch or dimmer switch.

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[rsl0311usmc]

9mm

Cutting random wires for unknown reasons and adding uncalculated circut protection does not sound like a good idea to me. I reccomend a systematic approach to any malfunction, most call it Troubleshooting.

First step in Troubleshooting: duplicate the discrepancy. If it melted a fuse instead of blowing, replace the fuse with a new one, see how long it takes for another one to blow/melt. Once you duplicate the discrepancy, you then have to find the mechanical reason for the discrepancy to exist by essentially cutting the problem in half: basically, what can you do to the system that makes it better vs makes it worse. That truck went somewhere near 4 decades without melting fuses, so something happened to cause it to happen...something either malfunctioned/broke from use or changed behavior due to age/decay.

Are there any modifications made to that part/system in the truck? What were you doing just before the melting happened? Have you been smelling melted plastic for a long time, or did it happen just now? Does it melt when all the lights are on?...just running lights?...all off? More story and background helps us figure out where to look.

My money is on the headlight switch or dimmer switch.

Sent from my SM-G970U using Tapatalk

Ok yeah I am leaning towards your approach. So today I cleaned up the whole truck harness and connections. The headlight fuse spot honestly doesn't look bad behind it. I also removed the fuse for the horn to see if it helps. The truck is pretty much stock except for it looks to be converted to 12 volt and has a toggle in the cab for battery one or two or both. My guess is it was a plow truck before. It also has the doghead mod with manual glow plug button. Now the fuse doesn't melt right away. It takes probably a month or so per fuse and half the time I can take I pick and tighten up the fuse spot and reuse the warped fuse. I daily the truck and if I were to guess I think the fuse may get hotter with the lights on versus not on but I can't be sure. Now someone has ripped the horn off of the steering wheel and there is a single red wire that has been cut coming of the horn itself under the hood which I have found interesting. Like mentioned before I removed the fuse for the horn today to see if there is any difference. But unfortunately it takes so long to warp the fuse for some reason and the only time I feel like the headlights really cut of is when I hit a bump. Then I can literally get up under the dash and take the fuse and push it in better or tighten the slot up and boom they are back on again.

 

[Jeepadict]

9mm??

So the melted fuse makes lots more sense now that you explain its terminals become loose. Google "loose connection resistance" and there's a cornucopia of technical jargon and engineering terms to support your problem. The circut in question is a high-draw circut, so with the increased resistance of the loose terminal you get your melting culprit...your pick trick is just delaying the inevitable.

Knowing now with the additional info, my instinct would be along the lines of replacing the fuse block...guys like @cucvrus would be better to elaborate on that topic than me. You could also dive into the TM to see what that process entails. Replacing the individual fuse block terminals may be an option too. If that's totally impossible, surgical excision of the line/load wires for the headlight circut for a properly sized inline fuse holder could be a pinch solution, tho not what I would consider ideal...tagging with some sort of label maker should be done for future use.

As for the horn: I'm feeling the horn wire is disconnected/cut because the horn button in the wheel is missing. IIRC there's a hot wire in the column that triggers the horn relay when it is grounded to the column. No horn button means loose hot wire and constant-on horn. The horn cap for the steering wheel is readily available across the web for $50-ish...you'll prob need the horn cap retainer kit too. Reinstall horn power wire and fuse, should be solid...it's a simple circut.

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[rsl0311usmc]

9mm??

So the melted fuse makes lots more sense now that you explain its terminals become loose. Google "loose connection resistance" and there's a cornucopia of technical jargon and engineering terms to support your problem. The circut in question is a high-draw circut, so with the increased resistance of the loose terminal you get your melting culprit...your pick trick is just delaying the inevitable.

Knowing now with the additional info, my instinct would be along the lines of replacing the fuse block...guys like @cucvrus would be better to elaborate on that topic than me. You could also dive into the TM to see what that process entails. Replacing the individual fuse block terminals may be an option too. If that's totally impossible, surgical excision of the line/load wires for the headlight circut for a properly sized inline fuse holder could be a pinch solution, tho not what I would consider ideal...tagging with some sort of label maker should be done for future use.

As for the horn: I'm feeling the horn wire is disconnected/cut because the horn button in the wheel is missing. IIRC there's a hot wire in the column that triggers the horn relay when it is grounded to the column. No horn button means loose hot wire and constant-on horn. The horn cap for the steering wheel is readily available across the web for $50-ish...you'll prob need the horn cap retainer kit too. Reinstall horn power wire and fuse, should be solid...it's a simple circut.

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I don't even know how 9mm got inserted sorry lol. Yeah I figured it was probably going to need to be replaced. Honestly everything else seems ok in there I just want a way to correct this issue. If anyone has replaced that terminal let me know the best way to go about it? Thanks

 

[Curtisje]

You've got a short somewhere. I wish I could help you narrow it down better than that statement but that's all I can do for you from here.

Once you fix it I recommend you install a 40 amp relay near the headlights, for the headlights. Wire the power from the headlight switch to the headlights into the relay switch. Wire the power into the relay switch directly to the battery (include an inline fuze, same amps as the headlight fuze in the fuze block). Wire the power out of the relay to the headlights. Ground the relay to the body. This will reduce the load on the headlight switch & fuze.

This is just my 2 cents. It works but you need to fix your current problem first.

Good luck. Semper Fi 0311!

-0306

 

[Jeepadict]

You've got a short somewhere. I wish I could help you narrow it down better than that statement but that's all I can do for you from here.

Once you fix it I recommend you install a 40 amp relay near the headlights, for the headlights. Wire the power from the headlight switch to the headlights into the relay switch. Wire the power into the relay switch directly to the battery (include an inline fuze, same amps as the headlight fuze in the fuze block). Wire the power out of the relay to the headlights. Ground the relay to the body. This will reduce the load on the headlight switch & fuze.

This is just my 2 cents. It works but you need to fix your current problem first.

Good luck. Semper Fi 0311!

-0306

This is a stellar idea. Companies like LMC sell a plug n'play specifically for this.

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[rsl0311usmc]

You've got a short somewhere. I wish I could help you narrow it down better than that statement but that's all I can do for you from here.

Once you fix it I recommend you install a 40 amp relay near the headlights, for the headlights. Wire the power from the headlight switch to the headlights into the relay switch. Wire the power into the relay switch directly to the battery (include an inline fuze, same amps as the headlight fuze in the fuze block). Wire the power out of the relay to the headlights. Ground the relay to the body. This will reduce the load on the headlight switch & fuze.

This is just my 2 cents. It works but you need to fix your current problem first.

Good luck. Semper Fi 0311!

-0306

Dang ok. Yeah I wouldn't be surprised with this truck. But wouldn't a short cause this thing to be blowing the fuse? In the meantime when I get some free time I will check the wiring. I wish I could have all new wiring for thr truck. Semper Fi thanks again

 

[Jeepadict]

Dang ok. Yeah I wouldn't be surprised with this truck. But wouldn't a short cause this thing to be blowing the fuse? In the meantime when I get some free time I will check the wiring. I wish I could have all new wiring for thr truck.

Oh, you totally can!! There's many companies that make new harnesses for old Squarebody trucks.

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[Curtisje]

Dang ok. Yeah I wouldn't be surprised with this truck. But wouldn't a short cause this thing to be blowing the fuse? In the meantime when I get some free time I will check the wiring. I wish I could have all new wiring for thr truck. Semper Fi thanks again

A short doesn't have to short all the time. A frayed wire that hits ground during a bump much like you described loosing headlights during a bump could be the culprit here.

 

[ODAddict]

I'm no electrician, but my experience is that a short will cause the circuit to open immediately (blown fuse or open circuit breaker). An overload tends to take longer depending on the amount of the overload.

But as Mr. Curtis indicates above, an intermittent problem could send you down a rabbit hole.

 

[rsl0311usmc]

A short doesn't have to short all the time. A frayed wire that hits ground during a bump much like you described loosing headlights during a bump could be the culprit here.

Ok I appreciate all the help. It looks like I am going to have to dig into her a little more. One thing I can tell you about the truck is the previous owner used house wiring to wire up a trailer hitch receptacle lol. I have fixed a ton of stuff already but you know how it is with these vehicles. Oh and let's not forget the wire nuts ha ha

 

[CSandoz]

I had this issue with my M1009.
I head out for work at 4am and one morning , half way to work, I had no headlights. I tend to drive my truck pretty regularly so I took the nuclear approach.

Order yourself the heavy duty light harness from LMC. I believe i paid something like 25 bucks for it. That should lessen the draw through the headlight switch itself. Clean all of your grounds and light connections. I replaced my blower motor and resistor also. Then the hunt for outdated resistors begins. i went through my entire truck searching for all of the resistors that were installed to cancel out electrical noise. There were quite a few, including one on the horn and for the blower motor
.
Since i did all of that i haven't had a problem.


If you look at the wiring diagram for these trucks you'll see all of the systems connected to that circuit.
Anything that causes an abnormal draw will cause the fuse to melt, like a slowly failing blower motor, or a failed noise suppressing resistor.

 

[rsl0311usmc]

I had this issue with my M1009.
I head out for work at 4am and one morning , half way to work, I had no headlights. I tend to drive my truck pretty regularly so I took the nuclear approach.

Order yourself the heavy duty light harness from LMC. I believe i paid something like 25 bucks for it. That should lessen the draw through the headlight switch itself. Clean all of your grounds and light connections. I replaced my blower motor and resistor also. Then the hunt for outdated resistors begins. i went through my entire truck searching for all of the resistors that were installed to cancel out electrical noise. There were quite a few, including one on the horn and for the blower motor
.
Since i did all of that i haven't had a problem.


If you look at the wiring diagram for these trucks you'll see all of the systems connected to that circuit.
Anything that causes an abnormal draw will cause the fuse to melt, like a slowly failing blower motor, or a failed noise suppressing resistor.

Ok does the harness cover all the lights under the hood? I ended up believe it or not finding a brand new oem wiring harness for under the hood also. What did you do with the old resistors for the horn and blower motor replace them or can you bypass them? I am also curious to know we're they are located? I daily my truck to and it's crazy how one little thing on it can cause such an issue. I love driving mine and people always ask questions about it and we're can they get one. I feel like the values of these things are only increasing

 

[CSandoz]

Ok does the harness cover all the lights under the hood? I ended up believe it or not finding a brand new oem wiring harness for under the hood also. What did you do with the old resistors for the horn and blower motor replace them or can you bypass them? I am also curious to know we're they are located? I daily my truck to and it's crazy how one little thing on it can cause such an issue. I love driving mine and people always ask questions about it and we're can they get one. I feel like the values of these things are only increasing

The wiring harness only covers the headlights. The factory setup powers the headlights through the light switch.
The aftermarket harness allows the switch to power a relay that powers the lights directly from the battery reducing the load on the circuit.

As i found the old resistors i tossed em. We don't need them. They were for reducing electrical noise in radio gear.
I'm pretty sure there is an article here somewhere on where to find them all. I'm at work at the moment, otherwise i would track it down for you.

 

[rsl0311usmc]

The wiring harness only covers the headlights. The factory setup powers the headlights through the light switch.
The aftermarket harness allows the switch to power a relay that powers the lights directly from the battery reducing the load on the circuit.

As i found the old resistors i tossed em. We don't need them. They were for reducing electrical noise in radio gear.
I'm pretty sure there is an article here somewhere on where to find them all. I'm at work at the moment, otherwise i would track it down for you.

Ok cool it makes sense. No rush I appreciate all the information.

 

[vanaisa]

guys, is it hard to search first topic in this forum? Really...

CUCV Helpful Threads

FAQ http://www.steelsoldiers.com/showthread.php?20600-FAQ-Thread-for-CUCV-s STARTER CUCV Stock Starter Circuit http://www.steelsoldiers.com/showthread.php?129483-CUCV-Starter-Circuit CUCV Doghead Starter Relay Modification...

www.steelsoldiers.com

 

[rsl0311usmc]

guys, is it hard to search first topic in this forum? Really...

CUCV Helpful Threads

FAQ http://www.steelsoldiers.com/showthread.php?20600-FAQ-Thread-for-CUCV-s STARTER CUCV Stock Starter Circuit http://www.steelsoldiers.com/showthread.php?129483-CUCV-Starter-Circuit CUCV Doghead Starter Relay Modification...

www.steelsoldiers.com

Thanks ball buster I will keep it in mind