Im Working on a 75 F-100 with a 360 and im blowing a 25amp fuse from the hazard flasher and stop light slot in the fuse block everytime I push in the brake pedal or full out the hazard ***. This whole problem started when my turn signal switch went out. I replaced it with a new one and shortly after my turn signals went out again I found a short along the frame and by the clutch pedal. So I searched all the wiring for any other shorts and fixed those two that I found and also replaced both flashers, all bulbs, and the brake light switch. Back to square one all lights work except for the turn signals (even the hazards work). I noticed when all the lights are on the right turn signal arrow on the dash stays on (even when not using the turn signals at all). So not wanting to bite the bullet and pay 85 bucks for another turn signal switch, I get a dorman- help turn signal cam and wire it into the turn signal switch replacing the old one. After I did this, thats when I started blowing the fuse everytime the brake pedal is pushed in or when the hazard *** is pulled out. I dont think I wired it in wrong theres only 2 wires on the thing theres gotta be something im overlooking? Im not an expert in wiring by any means so any advice would be very helpful and greatly appreciated.

 

got a meter? it's your friend. learn to use it. #1, search for continuity to ground on both wires.

 

Check all your grounds including cab to frame even if they look good pull them off and wire brush them them put some dielectric grease on them.

 

What they said.
Pull up the wiring diagram online or get a shop manual. That plus a meter will help you

 

Just a few good practice tips:

1. The turn signal cam kits are worthless. The wires in the original turn signal switch snake through the switch very tightly. There is little very clearance around the wires. When you install the replacement cam, you must solder/shrink-wrap or crimp the wires coming from the cam into your original switch. A crimp terminal or (good) solder joint makes at least 3/4" of the wiring non-flexible, meaning it can't snake around the switch. You might be able to jam all the wiring back in, but it will not stand the test of time. Clearances are tight and there are moving parts within that area, so any excess is very bad. I highly recommend to NOT use replacement cam kits and instead buy a new switch if the cam breaks.

2. What does the rating say for the brake/hazard light fuse on the fuse block? 25 amps sounds high. If the fuse block actually says 25 amps then nevermind, but if it's worn away, or you're just going by the fuse that was in there, then you need to look further. I only have a diagram back to a '76 and it says the fuse is 20 amps. You'll need to double check your fuse panel. The issue is, if you're blowing a 25 amp fuse then you definitely have a dead short to ground. But if the wiring is only sized to be protected with a 20 amp fuse, the 25 amp fuse is letting over 20 amps of current to pass through the circuit before it blows. I wouldn't rely on our forefathers at Ford to have added enough margin to make a fuse that's 5 amps higher safe to use. As much as it pains me to say, these era Ford electrical systems have numerous design flaws. What this all means is that even though the fuse blew, I would still be concerned about the health of the insulation on that circuit's wiring now. Insulation literally falls off wiring when it fuses out. You need to use a multimeter to test continuity to ground within the circuit, and you should visually inspect the insulation across the entire length of the circuit. And like I said, double check that fuse rating.

 

The turn signal arrow lighting up with the parking lights is simply a bad ground OR in my case turned out to be the parking light wire swapped with the brake wire on my taillight wiring (previous hack job).
The shorting out would be due to the cam kit installation.

 

it could also be a wrong type of bulb. if you have an 1156 in place of 1157 you get brake and parking lights swapping signals. any issue throughout either system would pop a fuse.

were the lights dim before you starting popping fuses?

the ground tabs in the bulb connectors are crap... always rusting out. and electricity will find a way back to ground even if it has to go through a different filament on a bulb.

 

1:

I've seen this problem occur with bad lamp sockets, and a bad light bulb itself. The bulbs are two fillament bulbs and I have experienced one of the fillaments breaking and crossing the other inside the bulb itself. Check the bulbs and light sockets, and grounds at the back of the truck behind the taillamp housings. Especially on the right side.


2:

Two different problems. You may now need a new turn signal switch, but when you get the new switch the first problem will still need to be corrected.

 

Thanks for all your inputs it really helped a lot. Turned out the cam kits are junk so I bit the bullet and got a new turn signal switch and brake light switch just to be safe. After putting those in I went around and cleaned up all the grounds and found out I was missing a lot of them so I grounded the motor to the frame, bed to cab, and grounded both the bed and cab to the frame. The front right turn signal socket was bad so I replaced that and now I have all fully functial lights without frying fuses once again turn signals, brake lights, hazards the whole nine yards!!!! Also the right turn signal light staying on all the time was cured replacing that bad socket thanks again everyone now time to move on to bigger and better things.