My 89 SE was giving me trouble a few months ago. The parking lights were staying on all the time (even when the car was off). In 89 the headlight switch & twight sentinel module were seperate items. My problem turned out to be the twilight sentinel module. I realize this info isn't going to help much but does show that the headlights & taillights had seperate circuits in the 89 module. Since the dealer thinks the problem is the switch (which in 94 has the module built in) you need to find a good deal on a replacement.

Is the switch available at the local auto parts stores?
Have you looked for the switch at any salvage yards?

You might want to ask the dealer if you can use the manual switch in place of the one with twilight sentinel. I was willing to turn the lights on & off to save $.

Yeah, thanks anyway, wish it was two parts, from what some are telling me along with the dealer (don't trust them) it is one piece.

Without DRL it is $314, with DRL it is $435 (forgot the exact prices at the moment, but both over $300.)

I checked Pick-your-Parts and there wasn't any 93-99 Bonneville. Loads of older ones, but nothing after.

That either means these are really great cars or are sold as soon as they hit the lot for parts chasers...

Someone had mentioned on this site they might have one in their bone yard, but he hasn't replied yet.

cheers
tom