I've tried switching the relays; there are three that are the same. No help! The GM service manual gives a (no dim ) trouble checklist to follow, but my car passes what is stated in the list. I've tried checking the rest of the lights and found that the fog lamps do not work either; only circuit or used wire that is related is the common ground at (G103) This was in the (no Dim) check list, Terminal 13 of the head lamp switch. I have not removed the battery to varify the ground at (G103)electron chaser said:I'm late for dinner already, but I'll check into this one when I get back to the shop tmrw. Doubtful you blew both bulbs at once, but could have had one blown and not noticed it for a while, then the other blew and PRESTO, no dims. OK, I took a sec to check the wiring diagram, there is a Low Beam Relay, needs to have power to the #30 pin of the relay for the low beams to ever get power. Check it with a test light, the relay will have the pin numbers stamped on it next to the pins/terminals. If you have power, swap out that relay with another one of the same number, common relay, sure there are a couple just like it in the relay box. Just did another check, you almost HAVE to have power at pin 30, that power is also the power for sunroof, some radio, seats, lots of stuff wouldn't be working if that circuit was dead. Swap out the relay with another one and let me know what happens. Good Luck.