There is only 1 wire to the temp gauge sensor on the front of the head next to the exhaust manifold.

If you earth that wire with the key on pos 2 your gauge should max out, don't keep it grounded too long though.

It might be a yellow wire, as smiley said been a while lol!

https://passionford.com/forum/ford-e...re-sender.html

Says white/red but that is an S2