Tail light not working

I put my daughter in a 2009 Cobalt. As we were leaving the house this morning, I noticed her right tail light was out. Brake light worked fine. I changed the bulb, which was burnt, with a bulb I had at the house and still no luck. I got a new bulb from the parts store and still nothing. I am getting power in the socket to both the blinker and the tail light, so I assume my issue is a grounding problem. Wouldn’t the tail light and blinker have a common ground? Blinker works, just not the tail light. Any suggestions would be appreciated.

Maybe you didn’t insert the bulb all the way in or you have a bad bulb.Also,do not touch the bulb with your bare hands,use a glove or paper towel to insert it into the socket because the acid in you skin will destroy it.

Are you using the correct bulb ?

3157 preferred, 3057 if that’s all you can find.

Double element bulb

Yes to the other comments. The ground is the same for both filaments and you can easily test for a ground with a wire one end to ground and the other to the bulb. There are two filaments in the same bulb. One for brakes and one for the light. Either the socket is bad or you’ve got the bulb in backwards.

I took out a 3057 and tried a 3157 first. No luck. Blinker works fine but no tail light. Tried the new 3057 with no change in the results. Test light shows power on one side and blinker on the other side. If they share a common ground, then I think you may be right as to a bad socket. As for the bulb backwards, I didn’t know that there was a reverse way to insert the bulb and will try reversing it tomorrow. Thanks.

see if inside the socket is burnt or corroded. also make sure metal tabs inside are not bent. if it is bent it might not be making a connection.

Some times a stronger current like the turn signal con make its way through a poor ground but a weaker one like the tail light cannot

So I was looking at the problem again, and noticed the 921 Bulb which appears to come off of the ground on the main bulb is also out/blown. Correct me if I am wrong, but common electrical would cause the main bulb not to illuminate due to a break in the current with the smaller bulb being out as well?

Answered my own question. No, smaller side marker lights up when replaced, bigger doesn’t.