After some exploration, I’ve figured out how to modify the foglamp circuit for a 2001 Explorer so that the foglamps stay on with the high beams. This mod is actually much easier, IMHO, than for the earlier models.
First, I located the relay box. It’s mounted to the same plate that holds the bottom of the airbox. I got into it, and here’s what I found:
1. There are sockets for a total of six relays, two large (the size of a conventional Bosch relay) and four smaller relays, in a 1 2 1 2 configuration. The six sockets were arranged like this, with socket 1 being toward the front of the vehicle:
1
2 3
4
5 6
On my Explorer, socket 1 was empty from the factory...