Tim, there are 2 circuits in the lighting system, one to light the lights, & one to raise/lower the pods. The lift mechamisms have separate circuits each side.
If the light comes on but does not raise/lower, then the fault is with the lift mechanism. Glovebox relays have been mentioned, certanly worth checking these out.
Underneath the 3 pin plugs that you have cleaned there should be an earth wire bolted to the bodywork in the engine bay behind the headlamp panel. Take these off & give them a good clean, then refit. These problems are very often down to bad earths.
Tony
<font size="1">1981 2L FHC Cavalry Blue
1980 3.5L V8 DHC Jaguar Regency Red - sadly sold!</font id="size1">