I don't think it was me, but I know how to do the relay..............
Don't have a picture, so you'll have to draw your own.
I'm assuming the temperature sensors grounds out when you want the fan on...........
Start with standard lighting relay
Terminal 30 is to battery
Terminal 87 to fan
Terminal 85 goes to the temperature sensor/switch (not ground)
Initially terminal 86 would be an ignition sourced wire so fan would only work when ignition is on. (green wire would connect to IGN)
You need 2 1 amp diodes and some wire to keep the fan on. (If fan was on when you shut down, it will stay on until the temperature sensor/switch shuts off)
Modify as follows
Insert 1 diode into wire from IGN to terminal 86
IGN ---- diode ->|--- term 86
Current now can only go one way from from IGN sourced wire
Add wire and diode from terminal 87 back to terminal 86
T87 ----diode ->|--- T86
This supplies power to terminal 86 once the IGNition is cutoff if the fan was running when you shut down.
Once the circuit is broken by the temp sensor/switch, it stays off
The diodes prevent current from going from IGN directly to fan (T87/86 diode), or from fan output back to the IGN when IGN is off (IGN/T86 diode).