More stupid duratec questions (2021 360S): single- or dual-speed fan?

[Austin David]

Is the fan a single- or two-speed fan?  I notice the electrical diagram shows two drops for high and low speed, but my fan has only two wire connection and as far as I can tell it's wired up to the cooling fan relay directly, which I assume the former ECU controls/ed with a simple on/off.  As in, with the ECU disconnected I can ground the correct relay pin and the fan comes on and sounds fairly loud, and I don't see any obvious second circuit for a higher speed.

 

Car is a 2021 Caterham 360S (Duratec) with new electronics.  On OEM electronics it behaved "normally" as in "fan cycles at idle" between 90-95C" and I feel like it was very much on/off but I did not test it before I ripped out the old ECU and harness.

[MV8]

What do you have a diagram of exactly? Is one of the two fan leads grounded or have B+ all the time or with the key on?

[Austin David]

Page 216 in the 2015 manual has this (attached).  It shows two plugs so I'm guessing there's a second fan in some version of the car?  My fan definitely only plugs into one of those two.

[MV8]

Looks like two separate fans. Would be odd to have four wires on one fan.