Tail lights are out on 1990 old mobile cutlass

Check the inside of trunk for the access to them. It may need bulbs. I have one of these, its dark at this moment but if you have issues getting to them I will check this out. The dealer book is bland instruction but here goes what it says. Remove or disconnect: 1) Open luggage compartment lid. 2) Four nuts securing trim. 3) Eight wing nuts. 4) Lamp housing. 5) Socket. 6) Bulb. To install reverse it. I have the instruction for the High mount stop light with or without luggage rack & side markers and all others too just let me know if you need those too.

P.s I do not think I ever owned a car/truck without getting the repair manuals except a 1965 F100 I had years ago. I view it as part of the cost to own it. Now that they can be found dirt cheap if you wait and look for them on sites like EBAY there really is no reason to not buy one. I paid $9.00 for this Dealership mechanic 1990 Olds Cutlass Calais Service manual, its about 2+ inches thick and covers everything and it looks brand new.

I had change out the bulbs and the fuse tail lights still don't work I have early in the month switch around headlight with the brights

Look for grounds for them and check the wiring to them may can use a multimeter to confirm power them and check for shorts.