A few years ago I bought a set of new headlight assemblies from China ($40 each if I recall - EagleEye was the brand). Really changes the car's appearance when you replace the hazy lens with new clear ones. Gives it a new-car look. Anyways, they came with new bulbs pre-installed. A few days ago I noticed that the low-beam had stopped working on one side. I've replaced a rear tail-light (brake light) once or twice in the 19 years I've had the car, but this is the first time I'm dealing with a headlight bulb. I still had the original headlight units - with their bulbs still in place, so I took them all out. I see they're all 2-pin (single element) bulbs. Sylvania 9005X/SLL 22N HB3A 60W and 9006X/S 22P HB4A 51 W. I forget which is inner (DRL) and which is outer (regular night driving) but I'm assuming the 51 Watt 9006 is the DRL. I was wondering if these bulbs are interchangable - I'm thinking that maybe in DRL mode the DRL bulb is given a lower voltage - otherwise there isin't a lot of difference between a 51 vs 60 watt light? And how does the high-beam work with this setup? I mean, these bulbs just have 1 filament - not like the old cars (4004 round headlight?) with 2 separate filaments (low beam / high beam).