The standard sealed beam headlights that came from the factory will turn yellow & get dim with time, the more you use them the quicker that time comes.
The halogen type will burn white & brighter out of the box then a new old style sealed beam headlight, but they stay that way right up to the time they blow out.
Of course keeping the voltage at 12-14 volts at the light helps. You can test your wiring by checking the voltage at the headlight plug, if it's anything lowered than about 1-2 volts then the out put of the charging system you will want to check it out for corrosion, bad switch and connector. this is were the relay system help, instead of losing any of the voltage through the wiring (Voltage drop) you run power to the light through a shorter wiring with the relay system, getting less voltage drop, and brighter headlights.
There are a few WebPages on the net now with Headlight Relay Systems on them, my site even has one linked above. It's wired for the GMC Quad headlights, but just drop off two of the lights for most Chevy trucks.
Another good page of my website to have a look at is the
General Wiring Tips page. I cover things like having good grounds & wire sizing just to name a few. Also you will find links to all the other Lighting/Wiring Project pages, which were done with 1960-66 GMC Trucks in mind, but most can be applyed to other & Older trucks as well.
truckernix, The amp gauge move UP because the lights are hooked the battery, and the power to charge the battery come from the alternator thru the amp gauge to the battery, so up is good because you are using more power from the battery so more power is need to fill it back up.
