1. Open the hood of your 1993 Audi 90.
2. Remove the negative battery cable as a safety precaution.
3. Locate the fuse box. It is situated on the drivers side, just behind the battery.
4. Remove the cover of the fuse box panel by depressing the two side tabs and sliding it upwards.
5. Locate the fuse you need to replace by examining and matching it up with the fuse diagram inside the fuse box.
6. Remove the fuse that needs to be changed with the needle-nose pliers. Use your fingers to slide the new fuse into the correct slot. Replace your fuse box cover and negative battery cable.
7. Start your 1993 Audi 90 and check the function for which you replaced the fuse. For example, if your headlights were out, turn on your headlights to make sure they now work.