Yep, likely a polarity issue. With an 1156 type of bulb, you will have to swap wires to the bulb receptacle, but you can test the bulb by putting 12v+ on the bottom contact and - on the bulb base.
Note that LEDs with 5050 SMDs are now outdated. Some chipsets like 5730s are more lumens per watt and more lumens per chip, and they can fit more chips on each bulb for significantly more light.
I recently acquired some t10 wedge base LEDS with 5730's that finally meet my expectations as to color and output, after much searching and money
wasted since 2007. These were 10 for 6$.
I have 20 and no failures yet. Can't say the same about 5050's driven hard for less overall light