Hi and Low Beam out at same time

Howdy Tray. Welcome. Some great and knowledgeable folks around.

Man, that had 2b some scary stuff. My suggestion would be to get the recall thing done asap. I'm thinking some sort of short. But the fuses being ok is perplexing if that's the case.

Perhaps something as simple as a disconnected wire in the harness? So tight in the 2'10, really hard to run down.

But again, hello and welcome!

 

I've had headlight relays trip out on two very-long-ago cars. It was temporary, they would come back -- temporarily, until they tripped again.

On the second, it happened just enough for me to realize that only the high beam tripped, so switching to the lower power low beam would halt the trip-out cycling.

Checking voltage at the lamp sockets should help separate simple failed bulbs from a relay (or other) problem.

 

There is separate fusing between high and low. Some cars have a fuse PER BULB. Consequently, a blown fuse will almost never put you in the dark. A defective dimmer switch can however, especially if it switches BETWEEN high and low (only one or the other is on at a time). I believe that on my car the low beams are on all of the time, indicating that only the high beams go through the switch. That may be true of all Gen III cars. The old single bulb systems switched between the two. The old sealed beam systems used a lower wattage filament in the low beam whenever the high was switched on (probably to provide the cool look of four beams running simultaneously).

This problem requires an examination of the simple headlight wiring diagram. It will show the possible common failure points that could take out four bulbs simultaneously. I wonder if the taillights and instrument lights fail also? That would indicate that the problem is in the light switch or the power supply TO the light switch. It has to be something common to ALL of the lights that are failing.