Issue with Lights

MEXICOWANDERER wrote:
I'll spell it out...choose one...

Bad design--crummy materials
insufficient load capacity

BUT IT ISN'T THE HEADLIGHTS

It's the tail lights and markers that go out. And the problem is within the switch. Idiots limited the circuitry to carry

Parking lights
Single (pair) tail lamps
Four upper clearance lamps

Switch on a push pull headlight switch on a Ford. Set to high beam. If you have a rig with say eight extra lamps, squeeze the extended knob stem after fifteen minutes. OUCH.

Brilliant

What do overheated breakers do?
Carry less amperage
Carry more amperage

DOT ratings specify a temperature for circuit breakers integral with headlight switches.

I've diagnosed far too many examples of this to have been fooled.

Use a Tyco circuit breaker and ease the misery and perhaps avoid a "your fault" collision at night.

Newer automobiles and rigs use circuit breakers and relays. Problem solved. Big Rigs use common feeders and as many as three tower type (White Rogers) relays to feed tractor, semi and trailer. I had to upgrade a bunch of triples in Nevada for Jartran. NVDOT was ready to shut down the fleet.

But Mex, he is NOT having a circuit breaker problem. The circuit breaker in the headlight switch is ONLY for the headlights, not the other lights the switch controls. He is probably having contact failure in the switch. The OP indicated his headlights were staying on when all the other lights failed.

Richard