Stop Light does not work... HELP

I checked the bulb, and it works,, just the left tail stop light doesn't come on. I checked the fuses and they are fine. does anyone have an idea of what is going on with my truck? everything works in the rear except from the left stop light. any help will be very appreciated... thanks.....

 

Are you absolutely sure you checked the right bulb?

Or - how did you check the bulb? Did you take a good bulb out of the right side and put it in the left side?

Did you check any electrical contacts, plugs, prongs, anything that isn't making contact?

Check any ground plugs/tabs (if applicable)?

 

yes, I did all that. I replace the bulb, I checked the wires with a tester and nothing. and I checked all fuses too. My guess the stop light switch? or maybe my two way responder alarm is causing a short circuit on the stop? when you remote start the car the stop turns off the car as a security measure...