What I am trying to confirm is how and where Ford originally grounded the truck bed to the frame. I know this may appear to be obvious with metal bed on a metal frame but with insulators and paint maybe not so much. It’s been almost eight years since I originally took my bed off. Fast forward through years of restoration and I find myself a little uncertain to how well grounded the bed may be.

I seem to recall a bonding wire with a sharp attaching clip at either end but I may be thinking of something else. I will probably go ahead and install something like this for good measure but I thought I’d ask. Any thoughts on where to install?

If you are wondering, yes, I’m doing some troubleshooting. Trying to rule out a bad ground as the issue. My flashers work until I hit the brake then it goes to solid on until the brakes are released. Same whether parking lights are on or off.

When I shoot the bed with the multimeter I’m getting .3 ohms which isn’t bad but typically I’m getting .2 so I think I can dial this in a bit though I’m not confident it’ll address the issue.

I thought it’s perhaps a bad turn signal switch but this worked prior to the new harness and the same issue when I use a jumper to bypass the switch.

I’m working with a new American Autowire 510342 harness. I’ve triple checked all other connections and it seems to be done right. I am trying to reach out to them for tech support but between working and being on pacific time that’s a challenge. Figure I’d see if anyone here has any helpful insights.

 

Your 4 ways are supposed to go solid when you hit the brakes. If they didn't, then if by chance you were driving with 4 ways on like some do in heavy fog, you'd have no brake lights at all as long as the 4 ways were on. If a vehicle has amber colored signals and 4 ways, those are independent from brake lights.

Your front park lights and rear tail lights have bulbs with two elements, a hotter one serves as turn signal, brake light, flasher functions. The cooler element is park or tail light.

 

Interesting thought… nothings wrong. I’d buy that if it were only the hazard lights but…

It does the same thing with the turn signals though. I don’t recall it doing this before and I’ve never seen another vehicle operate like this.

 

I did a little extra troubleshooting but disconnecting the rear harness. It still locks up the front lights. I’m confident it’s not a bed ground issue.

 

Oh ... well you didn't mention it stopping the signals flashing too when the brake was applied.

Turn signals and flashers get their flashes via two different flasher circuits. When you apply brakes, the brake lamps get power ... but if you activate a left or right signal, the power to that brake lamp is interrupted in the turn signal switch on the steering column and that "was" brake lamp element is then powered by the turn signal circuit through it's flasher for as long as the turn signal is on. As soon as that left or right signal is cancelled, the "was" a brake lamp returns to being just a brake lamp. Otherwise, one would have to have separate turn signal lamps. Four way flashers have no need to interrupt a brake lamp, the brake lamp is of greater importance than four ways ... so no provision is in place for them to override brake lamps.. The four ways flash off their own separate flasher, and to flash means they go off due to no power. As soon as you step on the brake, the rear brake lamps get steady power from the brake light circuit, and since the front hotter elements are connected through the flasher switch to the rear flashers, they too get uninterrupted juice and stop flashing, they too burn steady unless you turn off the flashers.

Your issue likely lies within the turn signal switch in the steering column. The turn signal switch is separate from the 4 way flasher switch, but they share a base behind the steering wheel. The brake lights are only intertwined with the signal switch to give it the ability to interrupt brake lights on the selected signal side. This happens under that long white (looks like pale blue on this one below) piece with the ends that cancel the switch automatically, there are contacts there..

The four way flasher sends it's flash current to both front and rear hotter elements, but when it's off there is no path from the rear and front hotter elements, that path only happens when the four ways are "on".

 

This makes sense. I believe every other possibility has been ruled out. Slightly frustrating as I recently rebuilt/refinished the entire column so I get to tear into it again. I should have changed but it previously worked. It may have broke during the reinstall. Is what it is. Thanks for the feedback.

 

I just did this fix last week ... I had replaced the switch long white a couple times and I guess last time, soldered the wire there where there is just a red and a white wire ... then maybe 2 weeks ago, one solder joint broke, the wire shorted I guess, blew my turn signal / back up light fuse #11, and since I already had the whole switch assembly (turn / flasher / horn / etc.), I did my swap of the whole assembly. It was where the white wire attached ... instead of splicing, I had just soldered the two connections last time I had replaced the white ts cam piece..