I got a 1990 Volvo 740 GLE non turbo and the headlights stopped working. A friend of mine had the same problem and said this may be caused by a faulty high/low switch. Can somebody explain to me where is this located on my car and describe how it looks ? I have checked the fuses and all are ok, the relay was tested and it tested good the switch is sending voltage to the relay but the headlamp connector does not have a voltage non for low or high beam. I know this problem can be caused bay many thing but I would like to start by testing if the high/low switch is the culprit. Any help will be greatly appreciated.

 

the high low switch is on the left steering column stalk. pull it towards you to toggle. the power goes from battery -> positive terminal (under driver side dashboard, its a little black pill box with a pile of red wires) -> relay 'K' (behind ashtray, its the 2nd relay from the left on the row closest to the shifter) -> headlight switch -> ... mmm, kinda complicated, but the light failure detector (big round relay in far left of farthest row from you in the main relay panel) and fuses 17,18,19,20, and the highbeam/lowbeam switch and of course the headlights

afaik, the only thing that stops all the headlights at once would be that relay.

the relays are a lot easier to access if you remove the trim around the cigar lighter, then remove the screw or two under there, then remove the whole little tray thats above the ashtray.

 

This happened to my old Toyota wagon a few weeks ago. Different than a Volvo I know, but the fix may be similar. My relay would make a buzzing noise when current was sent to it. Thinking the relay was faulty, I replaced it but the headlights still didn't work. So I removed the relay bank (underhood bolted to inner fender) to check connections. I found what the manual calls a "fusible link" that was pretty corroded. Cleaned it up and blammo I now have lights.

And yes, the night the lights failed I got pulled over by the heat. Turned out to be America's coolest cop, as he let me drive home in stealth mode. I didn't even have my license on me. Good luck.