having probs w/ taillights on 69 cutlass. i installed a new harness from american autowire. driver side light worked sporadically, but then i thought i fixed it. i moved to pass side which had a bad ground from dirt,paint, etc. i cleaned it up and it works great. but, my driver side tailight illuminates when lights are on, but no brake or turn signal. i have swapped bulbs w/ pass side, i pulled socked from taillight and ran a jumper to a good ground, i wiggled the bulb. no change. i figured if it lights, then my ground is good. any ideas on why no turn signal or brake light, but other side works. it's got me baffled

 

I would bet on the POS sockets. They ain't much [just a little better than the repos]

 

i played w/ it a little more and it appears no power is coming through yellow wire that goes to driver side socket and powers brake/turn signal part of light. i test pass side and can get reading on green wire going to socket controlling that side brake/turn lighting. is there a fuse that could have gone bad (though why would ps lighting work and ds doesn't). front turn signals work. any help would be great as this has become a little frustrating

 

Tail lights & running lights are all daisy-chained together.
Rear stop and turn signal power gets distributed by the turn signal switch and hazzard flasher switch if your car has the latter.
Make sure the contacts in the new harness are making good contact with the TS switch (like not bent, dirty, or coming out of the plastic connector).

 

harness was only for rear lights and connects to harness that runs length of car to trunk. could turn signal or flasher fuse be bad. everything works except rear driver side turn signal/brake. and w/ meter, i am getting zero power to socket w/ yellow wire. it worked last week, but after fixing ground on rear ps light it now does not function.

 

IF ONLY the rear right stop turn is dead, fuses and flashers are fine.

If the RR tail light works at the same time the stop light does NOT, then the ground is okay. If the RR tail light goes out when stop light is activated, ground is bad.

Check the connection right at the socket. As mentioned already, even some new repro sockets could have been made poorly. Stick a sewing needle into the wire insulation and measure with volt meter to ground (right to the frame or bumper).

Double check where the new harness plugged into the old. try to measure for voltage at that connection. If it is NOT there, it is possible the TS switch might have started to give problems coincidentally.

 

finally found prob. i was under dash checking w/ meter tracing prob. at steering column where wires from column go into a connector that hooks into another harness, i found the yellow wire had pulled out some. i was getting power on column side but not on other side of harness. pushed it in and prob solved. a little scary that those wires can be easily pulled out of connector. at least it saved by a turn signal switch which was around $70.
thanks for help