problem with rear lights

[HF]

when I turn the lever to turn my lights on one time, nothing happens. When I turn it one more time, only the front lights go on, the ones at the back not. The lights for my speedometer, oilpressure, oiltemp. etc. don't work either. However, when I stop the engine and turn the key to PARK, both front and rear lights work fine. Is this another grounding problem, and if so, where to fix the grounding, or is there something else wrong?

PS I put 5 Watt lamps in the rear fog lights fittings, so I can drive safely at night, but obviously this isn't going to work for the APK (dutch MOT).

[paul]

Check the following;
1. All fuses relating to the lights are ok and clean.
2. Earth connections at the front below the headlights.
3. Earth connection at the rear in the boot infront of the spare wheel.
4. The block connector to the left of the steering wheel which feeds the light
cluster switches(after removing the top / bottom plastic cowling) this can burn
out.
5.The switch cluster its self (you will need a meter or a test light to see if the
correct voltages are present.
6.The ignition switch block(again checking for correct voltages)

I will think of more if no luck with these.