'78 E250 brake and turn signal lights...
 

Greetings all: I've owned a '78 E250 for the past 33 years so I know the truck pretty well. Over the years, corrosion has taken its toll to the body and electrical system. I finally got around to replacing all four light sockets, cleaned all ground connections, replaced the light switch, and turn flasher. The lights are working OK until I turn the head/running lights ON. When the switch is pulled, the brake lights and turn signals don't work but illuminate very brightly. Both filaments in the 1157 bulbs are on. What am I missing?

I did a forum search for similiar problems but after seeing hundreds of near misses, I decided to start a new thread.

Mine had similar issues. First issue was that the ground connector inside the bulb socket was bent back and not making contact. 2nd issue was that the previous owner had replace one of the sockets and wired it incorrectly. He just matched up the colors rather than insuring they were the right leads. In mine the color scheme is not normal (as in green isnt ground etc).

Just take an electric meter and identify the leads on the van, then see which wires supply the power to which filament in the build.

With mine, the rear bulbs were brake light bright whenever I turned on the headlights. The brightness would overwhelm the turn signals.

Thanks for reply and advice. I've pretty much came to the same conclusion, I think I have some wires crossed. I had to stop the project to work on my daughter's car so back at it soon. I'll post my results when I get this thing working properly.

FIXED!!
 

I got back to the project and found not one but two crossed wires. One was clearly a bone head mistake but the other was a bit more subtle. I had the Van painted many years ago and some paint over spray obscured the the wire color codes on the right front light. If I was paying more attention, I would have pealed back the harness tape to confirm the correct wire colors. But noooooo, that's too easy.

Anyhow, the lesson learned is to replace all sockets, clean ground connections and wire correctly to renew the lighting system.

Well, sometimes the brown wires can look black and vice versa, with or without tape, paint et al to further confuse the issue! :) Been there, done that my own self--its aggravating needless to say.

And yes we all sometimes over think the most simple of things---it happens more often that I care to admit.

Glad this was an easy and cheap fix. :-X22

Ain't that the truth. I learned a long time ago when it comes to working on motor vehicles, forget everything you know about the principles of mathematics and the laws of physics.

I know there's an engineer joke in there somewhere!

Not a joke but the sad reality that Detroit takes short cuts and uses cheap as possible components. If they produce 10,000,000 vehicles per year and can reduce wiring by one foot, they have not purchased 10,000,000 feet of wire, two feet, 20,000,000 and so on. If they use a fuseable link imbedded in a wire harness, they have avoided routing wire to a fuse panel and that translates to $$$.

Agreeing with your point re: Detroit's approach to manufacturing---in fact that's pretty much the standard of all manufacturing, world-wide.

Disagreeing about fusible links however---they serve another purpose than saving money though. They tend to be in close proximity to an output device, intended to "fail" before an over-current situation has too much amperage traveling the distance to a common fuse block which can be quite distant.

We who work on anything are always at odds with those who design and build with a primary focus of manufacturing ease only.

Amen, brother!!! I cant count how many times I have had a few choice words for the individual who designed something I had to work on.......vehicles or otherwise.

I taught math and physics at a local engineering college helping young men and women earn their degrees. Some students had no business being in technology. Sure, they did their course work and got passing grades but as engineers, they scared the hell out of me.

Yanno though sometimes a background in engineering even if its never applied to a job in its field can be most helpful in other pursuits. If nothing else it gives a foundation in how things work which can't be all that bad.

If there's a "problem" with engineers it'd be most rarely if ever have any experience with the very things they design. Having worked directly with a product and its engineers quite a bit they'd seek me out for input about an idea or concept in the works. I'm sure we both learned a bit more from one another's perspective---it was very gratifying.

I recall working with a successful architect who earned much of his way through college as a sub-contractor in the building trades. I was a little shocked and more than a bit pleased he could strap on a tool belt and use tools as well--if not better---than a few other subs on that job. He knew what he designed far more than many other architects I'd worked with at the time.

More engineers need to immerse or familiar themselves with their design---its too bad there's not a program within a company to encourage or require that sort of thing. Let the bean counters figure out how to make something as good as we hope for a cost their bosses will enjoy! :)

And yeah this applies to anything made that can be or is intended to be serviced during its life.

Yep, that's a common problem for sure. I had an uncle who graduated Purdue in the 1930's and got a job with Vickers. He was required to stay on the plant floor for two years and learn how hydraulics were made before he was even allowed into the office areas.

I'm not too shocked about Vickers----they're either German or Swedish so intimate knowledge of most aspects of their products is important. It doesn't go unnoticed they were or still are one of the leading companies in the hydraulics business.