Scottss60,
Are you able to disconnect the wires going to the rear lights where they connect to the turn signal wires. If so disconnect the wires going to the rear lights. Now take a jumper from the positive side of the battery (or any hot 12v locations) and connect to one wire going back to the rear lights. Check and see if one of the bulbs lights and take note of which part (ie taillight or brake light). Do this check for each rear light. From your description there would be three wires to check in this manner. If the bulb does not light then there is only a couple of problems to check - no ground, broke/disconnected wire probably where connects to rear light and wiring harness, bad bulb. If the lights all work after this check then the problem has to be associated with the turn signal unit. Remember with electrical parts it is always best to try and check each section out and verify that it works then add the next section til it quits working.
Hope this helps,
Chuck
