Where do you find the auotmatic transmission fluid dipstick in a 99 cabrio havent checked fluid ever cant find it anywhere chck engine light on?

Many of the newer transmissions do not have a dipstick. It's probably time to have the transmission serviced anyway so take it to a transmission shop such as AAMCO and have the fluid and filter changed. Most of those places will do the service for about the price of the fluid, filter and gasket so it really is of no advantage to do it yourself, except for the dealers, they overcharge for everything. They'll probably point to some material in the bottom of the transmission pan and tell you that it means your transmission needs to be repaired. If it's running ok, don't bother. When they're done they will top off the fluid for you. As far as the "Check engine" light is concerned, you can borrow, rent or buy an OBD code scanner at most auto parts retailers that will help you figure out why the light is on. Realize that if the light is on, the computer has an error code for you to read, and it won't have anything to do with transmission if the light says "check engine".