Under the hood in front of the battery on the right hand side, it is a 20A fuse
Between the battery and the valve cover on the firewall.
I found three. One with the radio, one with the wipers, and one with the stop lamp relay.
The fog lamp relay is on under the hood and mounted to the driver side wheel well. It's to the left of the washer fluid resevoir, you'll see the wires. The fog lamp relay plugs in on the top.
Number 10 Torx works on a 2003 Jeep Wrangler. Fairly simple. Just remove the 3 holding the rim on, then the 4 holding the lamp in. I was able to change 2 lights in less than 1/2 hour.
NO relay just fuse.
The fog lamp relay is in the Power Distribution Box ( which is " live " ) in your engine compartment ( on the drivers side ) The relay is in the 2nd row from the drivers side and is the 2nd relay from the front of the box ( one of the small relays )
high beam lamp
The photocell would typically control a relay. The power to the lamp would go to one pole of the relay and the lamp to the other. The common wire and ground would go directly to the lamp. The relay would be normally open and would close when the light energy on the photocell decreased to an amount that would trigger a circuit to close the relay.
According to the owners manual - relay 203 is the Trailer Tow Backup Lamp Relay
The three relays starting from the left are fuel pump relay, horn relay and fog lamp relay (if equipped).
Fuel pump relay, horn relay, fog lamp relay and if there is a fourth relay, power door locks.
Rear lamp? Oh, I dunno ... maybe you need to turn around and look? A lamp isn't that hard to find ...