I stripped out the heater and fan module as part of my rebuild, have reinstalled it, all levers work and plugs installed, heater detent appears to be firm and cannot see a problem, but no blower, fuses are fine. The a/c button operates on/off as soon as the blower slider is moved from off to 1, then the a/c button lights up. What am i missing please? Its a 1997 GQ Diesel manual