head light relay question

[dzbowtie]

hey guys, the other morning i went out to the truck and the headlights would not turn on. i put a LMC relay kit on it about a yr and half ago. over that time, i have had the lights go out before and ive shaken the relays and they have come back on. i traced the power from the cab switch all the way to the relays. i removed the harness from the relays and jumped the power, which the lights turned on, both high and low when tested with the jumper wire. is there any way to test the relays, or do i just need to buy new ones. also, is there a specific 4 prong relay i need from a parts store or are they pretty universal? the LMC one are like $4. it says 30A/12vdc. thanks guys for any help you may have.