headlight problem

[03sierraSWB]

a buddy of mine has a 96 GMC suburban and he has the 4 headlight mod on his, but when he turns his highs on his low beams dim. anyone have any ideas why it's doing this? does he have a faulty connection? or could it be that the alternator is not giving enough charge?

 

p.s. - i'm not sure what brand he's using, but he did say that he has trouble with the installation, because the wire colors in the instructions were different from his truck wiring. (if i remember right...)

 

 

thanks for any info!

[TheBrokenMarine]

I think you're actually on point with both thoughts. However, I think that the voltage from the alternator could possibly be ruled out by raising the engine speed and inspection to see if they get brighter.