Trying to help a friend with integrated tail

[memper]

If I were to take the unit and put the ground on a battery negative and then test each of the four remaining wires to the positive directly, each light segment should light up yes?
This is how I test my LEDs (with a 9v battery). When he does this test only the signals turn on. No red lights at all. I believe his unit is defective.
Can't remember the brand. 12 is in the name.

[memper]

Basically the guy hooked up the unit and only the signals would work. No running lights, no brake lights.
I told him to do the battery test and he got no brake/run.
Am I correct in assuming the unit is defective?