[Accelo]

Persistence and a diagram will get you there. I noticed this is a air truck, a little more complicated.
Start with two things;
1) Does the orange wire have battery voltage? It should terminate at the relay. with the ORN, PPL,& DK BLUE

2) Does the brown wire on the fan switch (part of the control panel) have battery voltage

Typically one expects a single power source. This usually isn't the case. Just a warning.