I discovered a loose wire (power feed) in the plug connection at the passenger side rear brake/marker light. I reconnected it, all was working fine and now the brake lights won't come on with the pedal but instead work when the lights are on. Except sometimes the passenger side still won't come on at all. So I either have no brake lights during the day or only brake lights at night unless the passenger side decides not to work. What's up with that

DID NOT CHECK FUSES FIRST and look at all park lamps for dead. (all)
park lamps side and front rear right side fail?
is passenger on the right side?
K1500 you meant? Silverado 1500 ,2500 ,3500 or HDversions. I wll toss my dice again and is k1500
K= 4wd
PICKUP TRUCK NOT CAMPER SPECIAL OR UTILITY.
AND MARKER LAMPS TOO. (PARK)

the word tail means park, there are 8+ parking lamps
4 per side, the 4 corners and side marker lamps, all are called park now, (be silly to call front parks ,tails)
and 2 license plate lamps, and fuses.
fuse RR-park, see that there,?<<<< BINGO?
fuse LR-park (no)
FR-park
TRL-PARK

AND MORE
IT IS NOT THE PARK RELAY OR ITS FUSE OR ALL PARKS DIE,
SO WHAT IS IT. WELL FUSE BLOWN OR WIRES CUT
TO OR AT RIGHT SIDE PARK FEED.

You have a short in the cross over wire. Almost all cars and trucks have one main break wire with a second wire "y" in off to the passenger side . You could just wire in a cross over and disconnect the old one.

Check it out. It might have bad connection or burn out.
Good luck

mai

That's very odd, because the wiring for all of the side markers are just splices from the nearest park lamp wires- the rear tail light in the rear (and the license plate lamps are also splices from these tail lights), and in the front side markers, they are splices from the nearest park lamps. Do all the other park lights work and turn on with the park light switch on? I would examine the 2 wires from that side marker's socket to the wiring harness it goes into-the power wire would somewhere splice into the passenger tail light wire. The other wire would be a ground wire and also splices into a ground wire for the rear end. To be on, the marker lamp would have to be getting power from some live source. I can't imagine where. Does the rear passenger light work correctly?

In that harness to the rear where the park lamps run, there might be a live wire going to an electrical trunk latch switch, or maybe a trunk lamp. If the wires were frayed right beside the side marker wire, you could have some cross feeding of power between the two. Let me know, we always appreciate feedback.

If you have a test light, you can check for power at the light sockets and connectors. If you have power, you can connect the alligator clip on the test light to the positive side of the battery and test for a faulty ground...Good luck!

You have a bad connection at the rear passenger side turn signal. It is either the connection is corroded or a wire is loose on the ground side of the circuit.

its in the engine compartment in the fuse box on the drivers side next to battery

Usually one of the holes in the marker light where screw goes in, has metal contact where screw meets light, but if not, and they are not push in wire connection type from behind, then just run your white wire up through hole in housing, and bare the end & tighten it up under screw holding light to body. White should be ground, brown should be power.

marker lights and brake lights usually are separated -- they use a two filament bulb -- check bulb first -- sometimes the connections get dirty -- use electrical contact cleaner and spray the connections -- if that doesnt work -- there is a short in the wiring

check the plug in the trunk lid mine did that and the plug was completely disconnected, yours may just be loose, or have a broken wire