Definitely sounds like the headlight switch assembly on the column. The one with the blinkers... Mine has gone out twice. You have to remove the plastic column covering (like 4 screws underneath) then the switch is 2 small phillips screws (heads are facing you if you're in the driver seat) They can be tricky to get to; you'll have to turn the wheel a bit. You'll have to unplug the switch and pull it out to the left.

As a side note, after the second replacement of mine I noticed the plug actually has a short now too. Might want to check that too. If its shorted or loose, the symptoms will be very sporadic.

 

I have a '99 Discovery sII as well, but symptoms are a little different. The Driver's side tail wasn't working as well as the tail lights on my trailer. Mind you I bought a used trailer and had to re-wire it, but I had a trailer on my truck before and it worked just fine. After the re-wire of the trailer, I still had no tail lights on the trailer. I checked the trailer plug on my truck (it has been coverted to the 7 round RV plug with the appropriate conversion kit) and found that I still had no tail lights. I pulled the driver's side tail light and checked the bulbs. Nothing wrong with the bulbs. I put a test light on it and nothing. I pulled the passenger side light thinking it was the converter some how. Pulled the light off and tested the wiring coming out of the converter. Nothing on the clearance lights. Tested the tail light plug on the truck on the passenger side and now nothing. I checked the fuses and the under dash fuse was blown. I replaced it and still nothing on the tailights. I checked the underhood fuse and it was still good. I finally got frustrated and put everyting back together and just for the fun of it, I turned on the lights. Now the driver's side which had not previously worked was on and the passenger side was now the one that was out. What the hell?

 

hey man i have a gxl also i was having problems with my car also with tail lights and there is a fuse for the lights i will get a picture of which fuse it is and highlight it!

if its not the fuse replace the switch i know the headlight switch will turn on the headlights and the tail lights too but if you have a bad switch the headlights will still work but the taillights and the interior dash lights wont???

give me a call i can explain it better over the phone

1440-813-7983 im tony by the way
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mighty milk

 

Did you end up getting your problem with the dash / tail lights fixed? I am having the exact same problem w/ my 95 Disco and am looking for some info. I have checked fuses, disassembled the switch (found nothing wrong), but still have the problem. I feel your pain w/ putting the switch in between position 1 and 2. Every time you hit a bump, you hope it isn't enough to switch it back to a true position.