Hmm in that case you would definitely have blown a fuse somewhere. But the problem being that with the solenoid not opening at all (As if he had shorted the supply and stopped the solenoid getting any voltage) the valve should stay in its shut state, ie only letting turbo achieve 5psi of boost. You would almost have to have a leak somewhere that was letting a shitload of air bypass the wastegate, thus stopping it being pushed open to regulate the boost pressure.
All in all very odd. Especially that its now working fine...