both rear tail lights blink when turn signal is switch on

[dschoon85]

hey guys, I need some help. 1983 chevy Scottsdale, when I turn my blinkers on in either direction both rear lights blink, front works fine, then if I hit the brakes they stop blinking, and brake lights take over. tail lights don't work, and this all happened after a tranny swap. ive looked everything over around the tranny for any damage done during the swap and didn't find any, rewired everything from the back to the cab, and replaced turn signal switch, still doing the same thing, im out of ideas. any thoughts?


update: walked into the shop, and now my tail lights are on all the time, until I turn on my headlights, then they go out

 

[rich weyand]

Check your grounds. One from the battery to the radiator crossmember, one (heavy) from the battery to the alternator bracket, one from the passenger side head to the firewall, and the sheet metal ground (some had one on each side) at the tail lights.

Also, did you check the splices in the back? These are famous for going out, either open or shorted.

 

[89Suburban]

Any trailer wiring hacked into the factory harness back there?