Trying to solve one lighting gremlin prior to putting the body on.

The brake lights illuminate when the brake pedal is applied with the headlight switch off, but when the headlight switch is on or at the parking light (first) detent, only the left brake light illuminates when the brake pedal is applied. This is regardless of key position.

I'm using the RF harness with the vintage gauges and followed the wiring diagram with the following exceptions:

- I moved the orange/purple wire to the forward spades on the brake safety switch (as noted from other posts about the instructions being wrong)
- Using a DPST toggle switch for the hazards
- Using the RT turn stalk - but only for a turn signal; no horn, flash to pass, etc
- Using a RF rotary wiper switch

Other than the wonky brake light, everything else works in the various switch combinations. No issues either with the courtesy lights, dash lights, dash indicators, stereo, etc.

I have grounds at all four corners for the lights in addition to the main RF harness ground wire.

I've been checking my grounds, but is there anything else that could be the likely issue?

I'm stumped. Thanks for the help.