Hey Rheller,
There might be malfunctioning part/s or the connections are loose. You may want to check that.
I bought mine at hidextra, i used to have flickering issues when I installed my kit. Not knowing that I would need capacitors/ cancellers for my Ford. Since I installed the capacitors, I never had any issues with my kit.
I was in their facebook and I saw that they have a recent blog regarding capacitors & relay. You may want to check that out, reading won't hurt you anyway. Enjoy!
http://blog.hidextra.com/hid-relay-capacitors-part/