Sealed beam halogens a problem for stock wiring and switch?

[70ranger]

I replaced one of my headlights with a sylvania sealed-beam halogen and had no problems. Drove for a few months with no problems...maybe a year. When the other headlight went out, replaced second headlight with same type, sylvania sealed-beam (have to replace whole unit, not bulbs).

Drove infrequently with lights on for a couple months and then on a wet day the lights wouldn't come on when first switched on. A little smell of hot wiring and then lights came on and stayed on ok. A second time with same experience and decided I better figure out what is up. Since I smelled hot wiring smell in the cab right away, figured it was switch or dimmer. Lights flickered on and off before staying on, guess that was the breaker in the switch cycling on and off.

Tomorrow I plan to strip outer sheath off quetionable parts of each of the wiring runs and re-insulate with electrical tape, isolating each wire in the run with tape and wrapping the assembly. I also have a new switch to install. Have read the threads here and think I know how to swap the switch.

Two questions. First, can the wiring harness being soaked (there were rags from previous owner keeping a part of the wiring run soaked....jammed down between battery tray and fender) cause an increase in resistance and draw more amps?

Will the sylvania sealed beam halogens be too much of a draw for the stock system, should I replace them also?

Ok, one more, could this simply be an aging switch?

Thanks...

[390Nut]

Old switch. Your wiring is probably fine, but I would definitely check it out up by the switch, just to be safe.

You might consider one of these while you're at it.

[70ranger]

Thanks Paul, that relay assembly looks easy enough for me to install! I'm not really much of a mechanic (I'm an engineer so I'm probably starting at less than zero on repair savvy), but need to work on my vehicles myself for $$$ reasons. My '90 Mustang 5.0 vert is down too and has been for a few months....long story.

I'd like to order one of the relays, but will need to wait a bit.

I appreciate your answer. I'm guessing the sealed beam halogens are not an issue?

One other question....is it stock wiring when the run for the left headlight is part of the harness on the left side and the right headlight is part of the harness on the right side? Only your relay harness has a wire across the radiator between the headlights, right?

Plan to continue making the relay harnesses for a bit?

Thanks, again....

[390Nut]

Yep, your wiring sounds like it is supposed to be, one harness on each fender apron.

The halogens wont be an issue, they don't draw any more current than the older sealed beams do, they simply make more efficient use of the electricity to make a brighter beam.

And yes, my harness will be available for awhile.

[fordman]

i'm betting on a bad switch also.

[70ranger]

Replaced the switch today and that seems to be a good fix.

The first time I cycled the dimmer switch, the highbeams didn't come on. Second cycle (and successive cycles) = all good. I'll run back by the parts store and get a dimmer and swap that out too, just to be safe.

None of the electrical spades looked burnt, nor any wiring I could see. No cooked insulation smells. No worries now about going to a New Years party tomorrow night out in the sticks !

I think it would have taken me a bit to figure out the button on top of the switch and getting the knob and shaft freed from the old switch. It took a good bit of wiggling to get them seperated. Thanks to the old threads posted here at FORDification and thanks to the members who gave of their knowledge.

MUST SAY :

[fordman]

yea those floor mounted dimmer switches are prone to sticking and not working properly after they get older.

[basketcase0302]

70Ranger,
Cool you found the problem to be inexpensive.

Oh man...do I love my foot switch headlight dimmer.
I think it had to have been some rice-burning/or chebby guy who invented the, "need-three-hands" steering column mounted dimmer!

Basketcase

[uboughtwhat?]

I don't like the column mounted dimmer switch either........kept getting my foot caught in the steering wheel

[l1k2gadd]

The high-beam dimmer switch in my '68 F100 was stuck when I bought the truck. I removed it from the floor and turned it upside down and sprayed a bit of PB Blaster down the sides where the cap slides up and down on the switch. I worked the cap free from it's stuck position and started to work it through the on and off positions several times (now that the PB Blaster had set in). I reinstalled the high beam dimmer switch and it is still working today (so far).

I have found in one of my Mustangs, and now this truck, that the dimmer switch housing oxidizes and causes the cap to stop sliding up and down on the switch. I have now done this to two high beam dimmer switches and have been successful with both (again, so far).