I have a 1995 F150 with a 351. My problem seems to be with my headlights. When I turn the lights on, the engine dies; almost instantly. If I turn the parking lights on, the engine runs but will not accelerate; it just stutters and putters until I turn the lights off. It behaves the same at idle or if cruising, in park or in gear.
It may be unrelated, but I've noticed over the past few months that when I brake, my front drivers side parking light comes on dim, and my left blinker indication on the dash glows dim also.
If anyone has any experience with a problem like this, please clue me in; I love my truck and am getting pretty tired of driving my wifes car after dark!
Thanks,
Bruces150

 

I have a 92 Flareside and there is a ground on the fender under the hood. It should have a nut holding down several lugs. Tighten this and it should eliminate your problem. Mine would die with the headlights and die when the blinker would blink and come back on when it would quit. What mine was doing was feeding voltage back in on the ground of the computer.

 

You either have a bad battery, battery with a bad cell or severe corrosion under the battery connections.

My first bet without knowing condition of any of the above is that you need to replace the batttery.

 

Thanks for the quick feedback, guys. I'll check those grounding straps and have my battery checked out (I did have to charge it recently...). I'll post back and let you know how I made out!
Bruces150

 

I tightened up the ground straps, and replaced one on the undercarriage beneath the passengers side. I went ahead and replaced the battery, it was about 4 years old. But to no avail: the engine still dies with the headlights on.
Now, when I start the enigine the headlights glow dim. When I brake, the headlights get a bit brighter (which is wierd because the headlight switch is still in off...). If I turn the headlights on, the passenger side comes on full strength and the drivers side is much dimmer. With the high-beams on, the drivers side light actually gets less bright, and the passenger light get brighter (as expected.) Again, when I brake the left turn signal will glow very dim, and sometimes the left turn signal fails to blink.
I am stumped. Sounds like I have some electrical snafu somewhere. Could it possibly be the headlight switch?
Bruce

 

Okay, I found it!
Just like richham said, there was another ground strap with two lugs on it grounded to the front of my truck. The bolt had actually broken - the head was just hanging there suspended by improperly grounded headlight leads.
If anyone else is fighting a problem like this, remember that the drivers and passenger side lights each have grounds attatched to their respective sides inner fenders.
Thanks for all the help guys, now I can be Ford tough 24-7!

 

I fought that for about a month a few years ago on mine. I took it to the local dealership and they were stumped (didn't charge me anything though). I just drove around with the parking lights and some fog lights if I was caught out at night. I finally found that loose bolt on the fender and wondered how many other trucks had the same problem. You are the only other one I have heard of. Glad that I could help someone.