Update On The Taillight Issues - Now A Sparking Fuse

Lanse

Well-known Member
First off I'd like to thank everybody whose so generously helping me get these lights going! I messed around with it for an hour or so and discovered a few things:

-Truck (1984 Ford F700) appears to only have one fuse box, couldn't find a second under the hood as some suggested
-There are no obvious shorts - I've wiggled all the wires around for the lights and dont see anything new, this also didnt "adjust" their placement enough to "break" the short's connection
-There is no obvious "dangling" wiring, although I did find and remove a bunch I hadnt noticed before. This also changed nothing.
-The fuses concerning the lights are ALL working (multimeter indicates connectivity between their ports)

And the main discovery - is that the (aluminum) fuse gets HOT in that fuse box! It'll literally burn you if its been in there for a few mins. Also, it's started (or I've started to notice) that it arcs/sparks as its connected.

What the heck now? I've never had to diagnose/fix something quite like this before. I dont think its a grounding issue, as I replaced most/all the grounds back there when I installed the new lights, and as mentioned - they *were* working just fine... On a side note, when I wired this thing, I wired in the turn signals/tail lights/brake lights all to share a single lamp, per side - as it was when I bought it. Not sure if that'll change anything, however...
 
They don't work well with a grounded power source wire. Pinched or bare power wire some where. Time to run a new wire.
 
I had to laugh, it reminded me of a late friend, owned Ford pickups, always Fords, he was also a organic gardener / horticulturist / fruit tree planter / herb grower / etc. He used to take pruning shears, raise the hood of one of his Fords when he had troubles, and prune the wiring til it started. Seen him do it.
 
Don't know what the aluminum fuse is, might be a circuit breaker. If it is a circuit breaker, they can go bad and the burned contacts cause it to heat up, or you could have a pinched wire that is drawing excess current, but sounds like what ever problems you're having, you narrowed it to the circuit you're having it on. Good Luck. NOTE: a picture of the fuse box and a fuse location diagram would be helpful.
 
Okay, here are some pictures of the fuse itself and the fuse box. No, I don't know what the random wire hanging down is, that came with the truck... Also, I unhooked the tail lights and it still arcs, so I guess whatever it is, its not my wiring of those...
Pics here
 
If you have sparks and the fuse(?) is getting hot,you have an overloaded circuit or a short(+ crossed to-). Try unhooking 1 light at a time in the affected circuit,and see if short goes away.If 1 light is the cause,your wire colors may not be correct-in other words,the chassis and the new lights may not follow the same color path.Red is usually brakes,green right turn,yellow left turn,and brown is running/tail/marker light,and white is ground.USUALLY.At each light you may have to test each wire rather than following a 'color code',and hook up accordingly.Use your multimeter to determine which wire is ground first,and wire from there.Mark
 
The aluminum fuse is a circuit breaker.

There are a few things that can cause it to heat.

1. The circuit is shorted to ground, the breaker is heating up, opening, cooling and resetting. (Most likely problem)

2. The breaker is bad and has high internal resistance, causing it to overheat.

3. The connection where the breaker plugs into the fuse block is bad, high resistance, causing overheating. You should be able to see this if you pull the breaker.
 
Not sure but I think you have a 20 amp breaker where a 30 amp is called for. Hard for me to see. The 20 is hot because it is tripping. One thing for sure if you put a big enough breaker in you will find your shorted wire. I am not recommending you do that but if you do you need several sets of eyes looking for smoke and hands feeling the wires. Be carful as there is a limited amount of smoke it all things electrical.
 
AH HA you're right!! It is a 20 amp breaker in a 30 amp slot. Is this supposed to be? What would happen it I put in a 30 amper? Keep in mind, that the lights dont work and the
breaker gets really hot, the problem has both symptoms. Could it be that its getting hot and tripping because theres too much power going through it now?!? Why would this
happen now and not before, right after I had installed the lights?!?
 
30 amps would be the maximum load for that circuit. Usually the manufacturer does not load a circuit to it's maximum. The actual load on that circuit might be indeed 20 amps or less. Look for bare insulation where the wires go through any hole in the frame or body. Look around all of the corners. If a wire is hidden from sight pull on the wire to try to make the hidden part of the wire Visible. Finding a short underneath and behind things in close quarters can be a test of patience, especially for a tall guy like you. My guess is the short is somewhere between the cab and the back of the truck and it might be under some dried mud and grit that hides the bare spot in the insulation.
 
Some of what you say was done is confusing. The origional equipment tail/park and turn is one bulb alright but it has two filiments and two contacts (1034 or 1157 I believe). Are you certain new bulbs are direct replacements? Did you replace tail light fixtures or just the bulbs? In your picture there is an empty fuse slot marked"30A parking lamps/marker lamps/horn". Does the horn work? I don't believe that qizzmo in your hand was origionally connected to tail/turn lights. It look's like it might have been a head lamp relay. Have you by chance moved or are you still outside Ft Worth? If you are N.E. of Dallas it might be easier to trouble shoot it for you than tell you how.At this point you need to see how many amps are being drawn,getting hot isn't an accurate estimate of amp draw. Do you know how to put an amp meter in series with one of the battery cables or better still,the light circuit? You have to depend on a meter for something like this,otherwise it'll take days then make you pull your hair out.
 
Tool comanies make a tool for that. Another way is to use a out of circuit amp meter for alternator output, and have a friend use a jumper to bridge the fuse socket intermittently (keeps the wire from getting hot, while you detect. The kit I linked to works as follows:
The tube thing is a self resetting 15 amp circuit breaker. When attached to the fuse location with the wires, it switches off and on and off and on. this causes 10 amp current flow in the loom. The meter detects this current and is traced by moving the meter down the loom until the needle motion stops. it can take a few minutes, or more to trace connections and follow branching wires, but it will work.
One of your statements made me think some on the idea that the wrong bulb types can short a circuit. If a single pin bulb is placed in a double pin hole, LED or incandescent, the whole circuit can be cross fed into other circuits making for problems. 1157 standard bulbs have two filiments and replacements must be made to that standard. (No shaming in this last idea, I have seen it. Jim
finder
 
(quoted from post at 06:35:30 02/24/17) The aluminum fuse is a circuit breaker.

There are a few things that can cause it to heat.

1. The circuit is shorted to ground, the breaker is heating up, opening, cooling and resetting. (Most likely problem)

2. The breaker is bad and has high internal resistance, causing it to overheat.

3. The connection where the breaker plugs into the fuse block is bad, high resistance, causing overheating. You should be able to see this if you pull the breaker.

Whut he said BTW that breaker is for the 2 speed axle look below it, its labeled lust for you. It has nuttin to do with the lights turn signals are what your light problem is.
 
No, I'm not certian! However, I unplugged the tail lights and this changed nothing... I replaced all the lights except the headlights and front marker lights, and everything worked 100% perfectly at first...

The 30A parking lamps/marker lamps/etc slot held the pictured 20 amp breaker. I'm not aware of a head lamp relay, and I've not messed with the fuse box. The headlights are working perfectly. Yes, I'm still outside Fort Worth!
 
What the heck, how?!? I've shifted the 2 speed to make sure it works, AND IT DOES! You can hear the motor clicking to shift it. How is that possible if theres no fuse/circ
breaker? This just keeps getting weirder...
 
(quoted from post at 21:25:57 02/23/17)
(quoted from post at 06:35:30 02/24/17) The aluminum fuse is a circuit breaker.

There are a few things that can cause it to heat.

1. The circuit is shorted to ground, the breaker is heating up, opening, cooling and resetting. (Most likely problem)

2. The breaker is bad and has high internal resistance, causing it to overheat.

3. The connection where the breaker plugs into the fuse block is bad, high resistance, causing overheating. You should be able to see this if you pull the breaker.

Whut he said BTW that breaker is for the 2 speed axle look below it, its labeled lust for you. It has nuttin to do with the lights turn signals are what your light problem is.

Hobo, look again, there's an empty slot where he's pulled the 20 Amp taillight breaker, next to that label it says "2spd" with and arrow going to the side to the 30 Amp breaker that he hasn't pulled.
 
Just ordered one! Thank you!!

Side note - the LED lights I bought - they have 3 connections in the rear of them. One is ground, one is TURN, and the other is marked BRK/TAIL or something simuilar IIRC...
 
<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/Stuff/There_I_Fixed_It_zpstho839py.jpg">

You've got one of two things going on, you have a dead short downstream of that breaker (possibly somewhere near the cab marker wiring you said you were messing with when the problem happened) OR the connector on the fuseblock isn't making good contact with the wire crimped to it inside the block or where the breaker plus in. Mice could have even chewed the insulation off of wires to the horn relay. In the photo, the LH terminal looks bad/arced/heated.

Of course, if there's sparks when plugging in the breaker with the headlight/taillight switch "OFF", it proves you have a short between the breaker and the switch.

(Just for the record, we've agreed it's a BREAKER, not an "aluminum fuse", right?)
 
That works. I would pull out all the bulbs in the next attempt. This prevents the bulbs from being the issue. I have seen internally shorted bulbs, and solder bases that mush over and short to ground. Jim
 
(quoted from post at 08:33:41 02/24/17)
(quoted from post at 21:25:57 02/23/17)
(quoted from post at 06:35:30 02/24/17) The aluminum fuse is a circuit breaker.

There are a few things that can cause it to heat.

1. The circuit is shorted to ground, the breaker is heating up, opening, cooling and resetting. (Most likely problem)

2. The breaker is bad and has high internal resistance, causing it to overheat.

3. The connection where the breaker plugs into the fuse block is bad, high resistance, causing overheating. You should be able to see this if you pull the breaker.

Whut he said BTW that breaker is for the 2 speed axle look below it, its labeled lust for you. It has nuttin to do with the lights turn signals are what your light problem is.

Hobo, look again, there's an empty slot where he's pulled the 20 Amp taillight breaker, next to that label it says "2spd" with and arrow going to the side to the 30 Amp breaker that he hasn't pulled.

If you say so I am fer'it... Whut he said... :wink: Ford fuse panels you gotta luv'em :twisted: At least its labeled :wink:
 
I was being generic in my words. One reason to take them out is that the units have internal circuits that could actually short out. I have seen new bad electronic parts. Good evening, Jim
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top