Checking lights

[AL’ UM- MONEY]

Recently I rented a u- haul trailor. As we hooked it up the attendant ask me to activate the four way emergency flashers to check the light connection.It made me wonder if it activated both the tail light and brake light filament plus the clip lights as part of the running light circuit. If so seems like a easy way to pre-trip by your self. I realize it won't check the brake light switch but will it get most bulbs?

[dznf0g]

I always turn on park lights and emergency flashers to check filaments/circuits. (LEDs). I'm usually alone, so checking brakes is not an option, unless I'm in the drive with the AS backed right up to the garage door. Then I can see the reflection of the brake lights on the garage door.

[Silver Goose]

The flashers use the same bulb filaments and circuits as the brake/turn signal lights on the trailer. Doing a solo preflight on your trailer once you know your wiring is correct by switching on the parking lights and the 4-way follow by a walk around is a simple way to check that all the bulbs are working. The mistake the fellow made at the rental place was he couldn't verify that the turn signals were wired correctly by the 4-way alone.