So I am about to go on a long road trip [3000+ miles] in my F250 to pick up a new race car, and I have been going over things on the truck to get it ready today [new tires, replaced the heater core, new wipers, new headlight bulbs, new brakes].

The one last concern I had was that my left rear turn signal and brake lamps are not working, they have not been working since I pulled the column apart to replace the busted ignition tumbler a few months ago. All the other lamps [running lamps, right rear turn & brake, headlights and front turns] work fine.

Instead of trying to replace the bulb I swapped the one from the other side and still got nothing. So the next thing I checked was the connector under the dash that comes from the multi function switch. I checked the voltage at the right rear turn signal/brake lamp wire [orange/blue] on the connector and with the turn signal and brake activated there was voltage, however the left rear [green/orange] there was no voltage.

Does this mean my multi function switch is bad? Was there something I could have screwed up when I changed out the ignition tumbler? What else should I check. Grounds?

Thanks!!

 

Would seem to me like you either have a broken wire in the column or a bad switch. See if you can get your meter at the terminals of the switch, if no voltage there going to the left brake/turn then the switch is bad.