2000 Pontiac GrandPrix Headlight problem

I have an interesting problem that I am hoping someone has seen before and fixed. I have a 2000 GP GTP that has a headlight problem. The low beam lights will not come on at night. The DRL come on in the daylight, the highbeam lights also work in daylight. When I cycle the headlight switch at night, the dash lights come on but not the low beams although the high beams still work. I swapped one of the HL bulbs with a known good bulb but I had the same issue. I checked the fuse on the DRL and it is ok. I pulled the fuse for the DRL and tried the HL switch with no luck. I am wondering if it may be one of the following, HL switch, DRL sensor of the HL Relay in the fuse box. Considering the price of replacement parts I am hoping someone has the right answer. thanks

pull the DRL plug that is plug'd into the heat sink on the drivers side acces panal.

Does that help?

I pulled the DRL plug but it had no effect. I went to a couple of Auto Parts stores and asked them about it and they were stumped too. One of them even got out a new bulb to see if it was the problem, he got the same thing. We went through all of the fuses and circuit breakers for the headlight system and they were all ok. Tested the HL CB with a Volt-Ohm meter and it showed no resistance so it should be ok. I ended up ordering a HL switch to see if it may be the problem. The parts store said if its not the problem, I could return it which was pretty cool of them.
I took the car out last night for about a 20 minute drive, I had to use high beams the whole time. When I got home I switched to low beams and they worked!?!? I turned off the car and started it a couple of times and they kept working. This morning it is back to no low beams again. I really need to get a schematic for the car. I have searched on the web for wiring diagrams but have come up empty, does any one know of a good site to check that might have some?

www.clubgp.com

Someone over there might be able to help you out.

CarnutCass have electronic diagrams. Looks like the switch itself might not be working properly

I was able to get the schematics from my local Pontiac dealer. It seems that they no longer have it in books but on the computer and are willing to print it out for their customers.

As for the low beam problem...I ended up having the dealer trouble shoot the problem, $40, and they said it was the multi-function switch. ie turn signal, cruise, wipers, hi-low beams. The price for a new switch from the dealer was $350. Labor would have been about $170. I was able to order a replacement at Autozone for $210 and install it myself. I did have trouble finding the correct steering wheel puller since the universal ones won't work. I found it a O'reillys for a whoping $15. It didn't take too long to replace once I figured out the tools I needed and how the Air Bag is released from the steering wheel. If anyone else runs into this problem, reply to this post and I'll try to walk you thru it. later :o)