Greetings, all. My mom has a 1983 Volvo 240 sedan; it has the four-lamp leadlight configuration. It has developed a strange problem with the headlights. The low beams work fine. However, if the high beams are activated, the high beam on the driver's side illuminates (the low beam on that side stays on), but the high beam on the passenger side does not illuminate and, further, the low beam on the passenger side also goes off.

In case that is confusing, basically the two conditions are that either: (1) low beams on both sides are on; or (2) when the high beam control is activated, both high and low beams on the driver's side are illuminated but neither bulb on the passenger side is illuminated.

I checked all the bulbs and they all work. If I swap the high beam bulbs from their respective sides, the problem persists.

If anyone has encountered something like this, or has an idea how best to troubleshoot it further, I would welcome the suggestions. The nearest trusted Volvo mechanic is at least an hour's drive and we would have to leave the car with them for several days.

 

I think I have solved my problem. I saw on another forum a post about locating the relay for the headlights, behind the left side headlight. While I was rooting around in the engine compartment, trying to locate the relay, I jostled one of the wiring harnesses and both the low and high beams on the passenger side came on. Obviously there is a loose wire or a short in there. I do see quite a few wires that are missing insulation in some spots. I continued jiggling wires to try to identify the one causing the problem but I wasn't able to replicate it. So for now my mom will continue driving it until the problem recurs.

 

Look for a loose ground wire going to the right side headlamps.