brake lights/turn signals

[mark carrick]

I have a "73" F-100 and all of the sudden my brake light and turn signal fuses keep popping, when I replace the fuses the darn things work in my driveway while the engine is running and while I just have the acc' on;but as soon as I get rollin' to work I get about three or four uses of each and then the fuse blows again. I've visually inspected the wiring harness from the dash to the lights and can't find any evidence of short circuiting. Any ideas

[kaptnkaos]

Hey Mark...

That could be your turn signal switch itself...
Mine was doing that a little bit ago...

I went thru about 3 fuses on my '68 CS, until I got a brite idea..
I stripped a wire and wrapped it over each end of the fuse before sticking it back into the fuse block...
As soon as I hit the power...
poof... lots of smoke came pouring outta my steering column...
Blowing fuses is the first indicator that there is a direct short some where in the circuit...
Big puffs of magic smoke is usually the last one, it does help locate the short... although it is not the recommended method.
You can never put the magic smoke back in...
just ask 390Nut...

Chances are the TSS (turn signal switch) or the wires thru the column have a short in them...

Good luck... I hate electrical gremlins.. they really tick me off !!!

KaptnKA S

[seattle67]

I stripped a wire and wrapped it over each end of the fuse before sticking it back into the fuse block...
As soon as I hit the power...
poof... lots of smoke came pouring outta my steering column...

Kids, dont try this at home!

[kaptnkaos]

No kidding... lost in the ozone again...

KaptnKA S

[ford4x4fun]

I stripped a wire and wrapped it over each end of the fuse before sticking it back into the fuse block...
As soon as I hit the power...
poof... lots of smoke came pouring outta my steering column...

Kids, dont try this at home!

[mark carrick]

Thanks for your time fellas' I was hoping to avoid the old bridge the the fuse trick for fear of causing some sort of "real" damage; but I guess I'll try it.

[ford4x4fun]

Your a brave man!

[kaptnkaos]

hey ford4x4fun

He ain't gonna do it...

KaptnKA S

[fmartin_gila1]

I use a buzzer clipped across the fuse holder to locate shorts. doesn't pull enough juice to let the smoke out, but will quit buzzing when you have eliminated the short.
Fred

[mark carrick]

Thanks Fred, great idea.

[Underdog97]

One thing everyone seems to have missed is that you said you have a 73 truck. The turn signal switch in the 73 trucks were different from the 67 to 69 and 70 to 72 as they incorporated the emergency flasher switch into it, also there are two different switches for those trucks, one for the automatic and one for the manual transmission trucks. The difference is that the automatic switch base is a little bigger to accomdate a light for the shift indicator. Both of these switches are notorious for shorting out in the emergency flasher switch area, they get hot there and it's a bad design although it was good in theory. If you find it is your switch PM me as I have both types of turn signal switches (used) auto and manual transmission types as well as both the 67 to 69 and 70 to 72 TS switches. I sell them on Ebay for $20.00 which includes the shipping but for Fordification members will do $16.00 which would include the shipping in the USA. if anyone needs an emergency flasher switch for the 70 to 72 trucks I've got a lot of them!

[Underdog97]

In further thinking about this you may also want to check your brake light switch underneath the column, there's a chance the wires running to it have gotten hot if the fuses are constantly blowing and could be a sign that the brake light switch is arcing itself out when the brakes are applied.

[kaptnkaos]

Yeah Underdog97

I actually did catch that it was a '73...
I didn't know they had changed that much... my bad...
I thought they were the same 'cause the columns are interchangeable.

KaptnKA S

[Underdog97]

The columns are the same up to 75 except for the switch mounting plates. The column it'self will interchange but the plates are different although they will bolt on. I have seen the newer columns & switch installed on the older trucks but not the other way around and then the flasher unit wasn't completely hooked up. I was going to make a plug in adapter to run the newer style switches on the earlier style truck but just havn't had the time to do the homework on how & what goes where without hacking up the main harness. I still prefer the old style 70 to 72 emergency flasher switch that mounts in the dash over the T/S switch or glove box mounted switches. My next project I guess as I wanted to put a 79 tilt Column in my 72, and it's a completely different style from the 70 to 72 columns or even the 73 to 75 column although the wiring is the same on the T/S switch. I need to find the $100.00 bills under the dash pad like Fordman did

[mark carrick]

Thanks again guys, I'm going to have a go at it next weekend. I'll let ya' know how it all turns out.