[ACK]

If the grounds are good, check the bulb contact alignment in the tail light buckets. I was suppose to have my truck inspected last weekend, but had to bail because the brake lights didn't work, the rear right blinker didn't work, and the rear left blinker flashed when signaling to make a right turn. This was all due to the rear right bulb contacts being slightly twisted out of position in the tail light bucket, probably rattled lose by all the pot holes. I pulled out the bucket, cleaned everything off good, realigned things, and all's working fine again.