I attempted to do the quad hi beam mod on my Century earlier, but it won't work for me. I followed a how-to I found on the w-body forum, but for some reason, my low beams won't stay on. The only difference between what I done compared to the how-to was that I used a 40A relay, and 18ga wire for all connections. I also soldered the wires to the relay.. could that have maybe fried something in the relay? I'm really at a loss with this now.

Got it fixed. Turned out that the 4 or 5 places i tried to ground were bad grounds. I ended up grounding it to a bolt on the fender. Works great now

I know our wiring is a little thin from the factory..but isn't 18gauge a little small even for the factory on our wiring?

Thats what I was thinking, but factory is only 18, and the guy who wrote up the how-to used 18 and 20ga for most of it and haven't had any problems. I've been keeping an eye on it to make sure it doesn't get too hot, but it seems fine so far. I might redo it all if I can get some heavier wires, for the peace of mind.