Tail lights

[it_mike]

I don't want to sound like an idiot, but obviously someone played with the wiring for my tail lights.

I know the top amber light is the turn signal, but can you tell me what the large middle and small bottom red lights are supposed to be (specifically)?  I'm going to have to rewire this mess.  My biggest question is which one is the 'always on' light, and which is supposed to be activated by the clearance lights.

Thanks, Mike

[bevans6]

stock wiring is small amber upper light is turn signal only, middle large red light is brake light only, and lower small red light is running light only.  No dual purpose lights.  Running light is on with clearance lights.  Note that the brake light has two switches that operate it, it is on whenever the parking brake is on, and when the parking brake is off it works with the brake light switch as normal.

I installed a 24 volt 7" diameter LED light as my brake light, and since it had a low intensity running light capability I wired that up as a running light along with the small lower red running light.

Note that the incandescent 24 volt bulbs have two terminal knobs on the bottom, one is ground and one is plus 24V.  Even though they have the dual terminals, they are single filament bulbs.  The case of the bulb and socket is not ground, one of the terminals is.

Brian

[robertglines1]

really good explanation Brian.

[desi arnaz]

my problem is even worse, mine fill with water.  any ideas?/reasons?

[robertglines1]

Desi--new gaskets or silicon caulk.under lens

[it_mike]

Thanks Brian. Mine are currently all dual filament and the large are on whenever the bus is running.

Time to clean up the spaghetti!

[Ed Hackenbruch]

Desi, move to a drier climate or drill a small hole in the bottom of the light housing.  I have done both, not in that order though.

[bevans6]

Putting the correct single filament 24 volt bulbs in may be a good start.  The brake light bulbs are sealed beam, if they are full of water they are cracked, so replace them.  The turn signal and running lights are lenses over fixtures, they have drain holes in the fixture so water can drain out.

You have aired up the bus and released the parking brake, yes?  If you don't the large brake light will be on all the time that the master switch is on because the parking brake is on.   Don't forget the parking brake applies itself automatically if the air pressure drops to a certain level.  Chock the bus if you take the parking brake off to test the brake light switch.

Brian