I removed my tail light assemblies to clean them up and re-glue the back-up lenses back into the assemblies (before fall off), and to clean up the copper foil for better connections to the bulb holders, and when I replaced everything, I noticed something strange.

Maybe I never noticed it because I never had everything apart all at once, and mixed up the bulb holders before.

There are TWO 3-contact bulb holders (one each side) for the 1157 bulbs that work w/ the BRAKE light and the PARKING lights. They have 3 legs to make connection to the copper foil on the assembly, and use bulbs that have two contacts on the bottom of the base.

I noticed with the left holder in the right tail light the park lights illuminate the bright (brake) filament, and the brake lights illuminate the dim (park light) filament.

I brought the bulb holders inside and they are IDENTICAL with regard to position of the contacts for the circuit board, but they are BACKWARDS with regard to how the bulbs fit into the holder with regard to the two locating pins.

If you position both holders oriented the same, one holder orients the BULB itself 180 deg different from the other. That means the filaments are "turned around" with regard to BRAKE and PARK filaments.

The holders are, as I mentioned identical and fit in either side, but only illuminate the proper filaments if installed with one (a black bulb holder) on the LEFT side, and the other (bulb holder is tan plastic) on the RIGHT side.

Again, the differences are with regard to which side of the bulb holder accepts the "deep" locating pin (the one with the locating/orientation pin) near the base of the bulb. On one holder, the "deep" pin orients differently with regard to the 3-legs of the holder vs. the other one.

Both holders have 21w/5w and CP32/5 imprints on them, with no other numbers.

Please tell me I am imagining this!

I know someone is going to present me with a "DOH!" moment and I'm going to feel like Homer Simpson when it's explained!

Bob
(It is the COLOR that denotes the 180 deg "out" pin orientation, and are the foil circuits wired differently on the two sides to compensate?)