Volvo Repair: headlamps stopped working, low beams, high beams

Question
1992 940GL. On headlights on position, niether Low beams nor dash lights work but can flash high beams; In parking light mode dash & exterior parking lights come on; all fuses OK; round red headlight relay removed & disassemled, there doesn't appear to be anyting fried on any fo the boards? What am I missing?  ; where can I find a map-out of which relay is for what under the radio? ; (also have no voltage to rear window defogger?)- Thank you in advance!


Answer
Peter, did you check basics like fuses.  The red relay is just for taillamps, etc.  The headlight relay is one the J relays.  Swap them around and see if the lights work.  The defogger has a relay also but I forget which one it is.  Best source is the factory manual from Volvo but you can get a wiring diagram on Ebay on cd.  Roger

Peter, never heard of such a thing.  Someone must have boffed something up installing the radio.  Makes no sense and I've never seen that happen.  Thanks for the input.  Roger