99 Cabrio with electrical issues

I've learned alot of good info from this forum and hope you all can help me with this problem. I have a 99 Cabrio GLS automatic convertible. Recently at start-up the ABS and Brake dash lights remain on. When this happens, several accessories like the windshield wipers and heater/ac won't work. I took the car to a localk dealer. They stated the problem was in the ingnition and replaced it at $600. Everything was fine until the first time it rained and then........ the problem seems to occur when the temperature is below 60 degrees (I'm in FL) or when it rains. Any suggestions/solutions?

Also the car came without an owner's manual. Where do I check transmission fluid? I can't find anything under the hood.

The ignition switch electrical portion is bad. Its the only thing that causes all 3 of those to not work (abs light, wipers, lights, and sometimes radio)

ALso I would have the 2 battery grounds under the battery tray cleaned.