Diesel pump electrical problem

[Hoyt 79]

Hello almal
I am having problems with the Fuel cut solenoid on the injector pump of an 5l engine.The wire to the solenoid gives 12.45V when I turn the key,but it does not engage (no clicking noise).But if I put a wire directly from the battery it clics(engages)
Another problem is when the AM1 FUSE is removed the glow plugs stays on the correct time as it sould,but then there is no power to the injector pump ,but as soon its replaced and the key is turned ,the glow plugs comes on and immediatly switches off,but then there is power to the pump.
I am not so clued up with the electrical side of things, so I will appreciate any help I can get.
I must just add that it is a bakkie that rolled( 5L 4X4) ,the body was completely destroyed,i then found a cab and loadbin from a 5L-E and I am using the 5L-E wiring harnass that came with the cab, I just changed the plug on the pump from the old harnass.
Thanks Hannes