yeah they can be hard to find online, dont know why. took me about a month and half of looking before finding a set on ebay. you can always get them from a dealer, though i checked on the price, here they were going to cost around $100 a piece.
i dont know know if you know that the wiring it a little bit different. the explorer uses two bulbs in its assembly; a 3057/3157 for the stop/turn signal and a 3156 for the reverse, while the mountaineer uses three bulbs in its assemblys; a 4057/LED assembly for the stop, a 3157 for the turn signals, and a 921 (i think) for the reverse.
also, while i was doing a test fit i found out that the assemblys do not quite fit. as they appear to be just a tad bigger, or it could be because of the plastic "grill" that covers the assemblys causing it not to fit right. I have not had the time to really look at it to find out why they are not fitting right.
