Where is the power antennae relay located on a 1999 4Runner?

You need to pull back the inner fender cover on the rear of the pass front wheel. There are 3 or 4 screws to remove and a couple plastic clips. If you are careful you can pop it off (and later onto) the plastic clips. You will not need to remove the entire inner fender cover, just part of it. It is pliable and strong so you can muscle it out of the way. Hope this helps.