I have a 79 f250 2wd. All the lights work (headlights,turn signals, parking lights) except the the tail lights. Fuses are good bulbs are good, I tried to check the wiring for any possible shorts and came up with nothing. I tried searching the forum and the only thing I found was that the brown wire is power. Could that be the culprit? Another thing is I checked the grounds and ended up replacing the ground straps. Still no tail lights. What could be the possible culprit? Any help is appreciated
I have read that the taillight bulb housing or socket can cause problems. Also ck the grounds inside the tail light housing area (where the lens goes in the bed).
Head light switch?
Here's what the factory wiring diagram says: for rear lights
Blk/rd= backup lights
Black= side marker, tag lights (on styleside)
Brown=tail lights, tag light (on flareside)
green= RH stop and brake
Yellow/blk= LH stop and brake
Rear light wiring
BROWN: running light circuit
YELLOW with BLACK stripe: driver-side stop/turn
GREEN: passenger-side stop/turn
BLACK with RED stripe: backup lamps
73 & 79 headlight-marker lights use same color codes
Brown= side marker and parking lights
White-blue trace= turn signal
Red-black trace= Low beams
Green-black trace= Hi beams
Flat bed wiring…
Brown= Run Light
Green= Brake light- L
Yellow= Brake Light- R
Black= Reverse Light??
Just wired my front lights. The brown wire is the marker light (side and turn) it is also the top wire on the turn signal socket (three wires in a triangle). The black is ground of course. The white/blue it the turn signal.
Thanks 77 and hio for the info that will definitely help and 79ford I did notice the pedal "falls" down a little and it does cause the brake lights to come on when I pull it all the way up the brake lights go off but I still don't have tail lights
The brake light switch works because when I hit the brakes the brake lights come on. Could it still be bad causing the tail lights to not work? How would I check the switch
You said "All the lights work (headlights,turn signals, parking lights) except the the taillights."
So I assumed you meant brake lights were the ones not working since I consider parking lights and tail lights the same thing.
For your "tail lights" I would say more than likely you have a bad socket. I've replaced a ton of them.
The bulbs also have a tendency to wear down the contacts. So.... check your bulbs as well. Also use dielectric grease when you go back together. This keeps the corrosion away and helps with the vibratory wear on those contacts.
First question are the rear side marker lights working
Do you have a test light or multimeter if so I can help you narrow it down a lil
At the rear drivers side of the truck near the end of frame rail there should be a square plug.
This is the harness for all the lights for the bed
Unplug this turn lights on and check all 4 prongs on the harness from cab side with the meter or light if one lights up then you are getting power from the cab and now can narrow down to harness to bed side of circuit
There is no excuse these days for not having a multimeter. Harbor Freight provides a coupon for a free multimeter and if ya can't find a coupon, they are still only around $10... that's two Starbucks lattes or three beers from the local watering hole. If in CA, then it's only two beers.
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