Glad to have you here with us in the forum.
I can't help you with your Rexall, but on my DS it is located in he water bay, in the back (almost hidden).
Tony & Ruth........... FMCA#F416727
2016 London Aire 4519, Freightliner chassis, Cummins ISX, 2018 Jeep Wrangler Unlimited, Blue Ox Avail with AF1. TST 507 TPMS