No, I didn't stop there. I did all the tests that I could do. I didn't do 1 test because the prong I was supposed to check wasn't on the switch. I have another pic so you can see what I mean. imgur: the simple image sharer

And you're probably right about the open circuit not blowing a fuse. I was just excited about finding a problem and hoped it was the answer to my issue.

 

The new turn signal/hazard switch didnt change anything, but it does look newer which is a plus.

I decided to test continuity to ground on the wire harness that the flasher plugs into. The only wire continuous to ground was the black wire that lands on the prong labeled "E" on the EP27 flasher. Im certain thats the ground wire.

I turned the flasher button on and tested the r/w wire, which is the hazard wire according to diagrams sent from Rod, and the middle prong on the flasher harness was continuous with ground, but im sure its just reading through the bulb filiments.

The fact that only the black wire was the only one that was continuous with ground tells me that the problem is after the column switch.

I think the circuit goes.. battery>fuse box>flasher>column switch>lights
I think the problem is between column switch and lights.

I also took out the front and rear passenger turn signal bulbs and my meter read continuous to ground from both prongs inside all passenger side sockets.

I took out the driver side rear bulb and only read continuous to ground on one side of the socket, which is what id expect from a non shorted circuit.

 

I thought I found it again. I took out all 3 bulbs in each of the rear tail light assy's and all 3 bulbs out of both Front blinker assy's. while taking out the rear driver side bulbs, I noticed the whole bottom section was full of water and the bulb was busted, it was the reverse light. The busted bulb was under water.

I took the bulb out and dried the socket, stuck a new fuse in, tried the hazards, and POW! it blew again.

So, the fuse blows with no bulbs installed.

Just for s&g I took the entire instrument panel/gauge cluster out to see if it would still blow, and it did. I took it out for 2 reasons, because I know wires go to it for the turn signal/hazard indicator, and so that I could see more wiring hoping to find a wire touching metal, which I did not.

This issue has beat me to close death, but I'm not giving up yet!

 

found another reason to stick a new fuse in and try it. while inspecting the underside of the truck, near the front driver wheel, I found a wire that had been rubbing the front axle and was almost rubbed completely through.

At one end, the wire looked like it bundled with the light wire, at the termination end it landed on the wheel by the brakes. Anti lock sensor? I dont know. All I know is that once again, the fuse blew when I energized the circuit.

I think Ill got to the parts store tomorrow and get a circuit breaker that I can reset. I saw it today for $15. I have 1 more 15a fuse in my third 5 pack that ive bought, which costs $3.99 per pack.

 

Or you could replace the fuse with a light bulb. When the bulb goes dark you've found the problem

 

That's a bummer.

Per the wiring diagram, I agree that only one wire should have continuity to ground at the flasher. I can't confirm it's labeled "E" but it would be the only black wire connected to the flasher.

The wire should actually be a w/r (white with red tracer) according to the diagram versus a r/w.

Since the fuse only blows when the hazards are turned on, that says the issue is either with the switch (which you've now replaced) or something after the switch.

Yep.

Are the wire terminals at the MFS something you can pretty easily remove with a terminal extraction tool? If so, you might try removing the terminals for the light outputs, the insert them back in one at a time until you find that one that is causing the high current drawing. Replacing the fuse with a test light as suggested by 87 XLT is a great idea for checking for the high current draw. When re-inserting wires, I'd suggest the light green wire being second to last and the W/LB wire being last since that wire is for the right (passenger) turn signals.

You could also remove the trailer tow relays to remove that portion from the circuit to see if that solves the high current draw.

-Rod

 

I'm not sure I understand putting a test light in place of the fuse. Wouldn't that just draw current until the bulb burnt out or wire melted??

Well I disassembled even more of the truck today trying to find this short, with no luck.

If you'll take a look at this image, you'll see a blue circle and a red one. I found the joint in the blue circle in a wire harness under the dash. I'm tempted to cut the wire that goes to the indicator light and see if the fuse holds. Or cut the wire that goes to the exterior lights to see if the indicator lights work while hazards are on. I'm almost certain that the wire to the indicator in the instrument panel is good because I could follow it pretty much all the way from harness to harness. With that said, I've also ruled out a short in the indicator bulb because the instrument panel isn't installed and the fuse won't hold.

I haven't found the joint in the red circle yet, once I find it I think I can cut the wires and test the front and rears lights separately to narrow it down some more. That way, I should know if the short is in the wht/lt blu or the org/lt blu. imgur: the simple image sharer

I'll look into removing the trailer tow relay.

 

I would not both cutting the wire to the instrument cluster indicator since, like you said, you were able to follow that wire and the fuse still blows even with the cluster removed. Considering the amount of water you found in the rear light housing, along with a broken bulb, that portion of the circuit seems like the most likely culprit.

Installing a standard bulb test light (not a new LED test light) in place of the fuse would limit the amount of current that the circuit can draw since the test light will only allow as much current to flow as the bulb requires to light. So if there is no current draw, meaning the fuse would not be blowing, the test light will remain off. If there's a little current flowing, the test light will glow dimly. If there's a short that would otherwise blow a fuse, the test light will glow at full brightness. The test light would glow because the short is allowing the circuit to be completed through the short to ground.

In your case you'd probably want to remove all the hazard light bulbs to prevent a false sense of a short. Then, when you enable the hazard lights with the test light in place of the fuse, the bulb of the test light will probably blink brightly at the hazard light flash rate. That's due to the short that is blowing the fuse.

Let's say the problem is with the trailer wiring circuit. With the test light still installed, you remove the trailer lighting relays. That removes the short to ground and now the test light will either flash dimly or not at all. That's tells you that you have found the circuit causing the fuse to blow without blowing another fuse.

As for the areas you circled in the linked image, you'll want to check the schematic symbols guide to see what that symbol refers to. It doesn't appear to be a splice since splices are indicated with a dot and a reference designator that starts with "S" as shown elsewhere in that diagram.

-Rod

 

Guess what...

I fixed it!!!

All blinkers work and so do the hazards! It didn't defeat me, I totally pwn'd that problem! Hahaha.

The issue was definitely in the orange/light blue wire going to the passenger rear tail light.

While tracing the wire, it eventually led me to a wireway on the passenger side just inside the door on the floor, under a long piece of plastic that looks like it's just made to step on and hold the carpet down. The wires in the wireway looked great, there were probably 30 wires total. When I picked up the wires to inspect the underside, I noticed 4 self tapping screws that had been installed from the underside of the truck to support the step boards. The screws damaged at least 3 wires in that bundle. Orange/lt blu was the most damaged.

The wierd thing it's that the step boards are the same color as the truck and molded to fit from wheel well to wheel well. I thought they were put on at the factory when the truck was made. I guess not tho. I fixed all the damaged wires and relocated the screws. I checked the same area on the drivers side and had to fix 1 damaged wire there. There's no telling what all this fixed but I'm very happy right now.

I also noticed that the bulb holder on the backside of the instrument panel had a missing bulb and socket. It was for the abs light. I think it was taken out intentionally because the previous owner didn't want to sell it with the abs light on. Well that's fixed too. The abs wire going to the driver front wheel had been rubbing against the front axle for ages. It was rubbed through and copper was laying against the axle.

The truck is completely put back together now, and ready to roll.

Pics attached to show you what I found.

Here's the underside, where the screws were attached for the step board support. http://imgur.com/OWQ0j5R

This is what it looked like in the wireway http://imgur.com/gJM67JH

This is what wires look like when you run a self tapping screw through them. http://imgur.com/Jflsi4S


edit.. Thank you, to all that replied trying to help. Especially Rod, your diagrams helped tons.

 

Wow, that's awesome that you found this issue and got all the wires fixed. That was not an easy one, and no wonder it took awhile to find. Who would have though the issue to be inside the truck in a protected wire raceway. Good find, and thank you for following up with what you found.

-Rod