JZS171 Fan Control - Haltech

G'day guys, hoping someone can give me a hand with trying to get the factory JZS171 Crown fans switching on.

Customers vehicle has an E2500 with a Patch Harness.

Fan Trigger wire is pinned out to B18 (IGN 7) i have attempted moving the pin to another DPO with no luck.

i have tried setting it up in duty cylce & Switched still with no luck.

i have tested the fans using my powerprobe and they both run perfectly.

i have 0.2ohms from the small trigger wire at the fan plug back to B18

i have 12v across the board at the 3 pin plug and 1 plug.

Tho when set to duty cylce i have 7v at 100% duty and 12/13v at 0% Duty.

When set to Switched i have 12v at the small trigger wire on the 3 pin plug, when changing the High or Low state i have no change in Voltage.

im hoping someone on here has wired up a haltech to factory crown/jzx110 fans before and have more knowledge than i do.

Cheers in advance

Hopefully someone with specific knowledge will be of more help. I have no knowledge of that vehicle.

In the meantime one generic thought would be:

If the circuit is ECU -> relay -> fan, have you confirmed the fan relay(s) are controlled by a low side (ground) input?

I ask because it's possible you're only altering the signal to the side of a relay coil which is usually the constant side.

If the car has a fan control module, then this gets a bit less straight forward, unless you have a service manual which details the pinout and expected behavior, voltage range of each circuit. If you can get your hands on a service manual or similar documentation, that might speed things along for you.