To pull the switch, you have to pull the steering wheel. Troublesome and annoying, but not that hard, there's only three screws to remove inside and then the wiring harness to unplug.
From what I can see in the wiring schematic there is only the combo switch and the rotary light control switch in the circuit, no control relays. The relays would have been my first choice, but since there are none, the next likely suspect is the combo switch. The intent is to replace with a salvaged part, and if all is OK eventually replace with new..... I just don't now these cars well enough to pop for very expensive new parts in an attempt at a repair.