How can i fix my Daf cf 250?

I have a daf cf 250 tipper with a Atlas 95/1 grab crane fitted on an 03 plate. The problem is the pto wont engage and the electrics to the crane are dead. The switch on the dash is working. The air switch on the side of gearbox works when i run a direct live to it and the pto engages. I have checked the wires from air switch back to the main harness and they are ok.The problem seems to be between the switch and where the wire comes out of the main harness to the air switch. If i use the direct live to the air switch the hydrolics work and i have to set the engine revs on the hand throtle, i can then use the crane but the crane electrics are still dead.