[Monkey Wrench]

not as familiar with some with this circuit but Im imagining this might be a problemwith the high beam relay.

if you just think how a pen works , you click the button it goes out, click it again it goes back in. It might be that the relay works similar to this and it failed, maybe the contacts welded. I don't know where it would be located but it would probably feed the high and low beam wires to the headlights. some cars use a foot switch so I guess one could convert to that if they couldn't source the signal switch or if it were really expensive. I like that better as on the highway my left foot isn't that busy usually so I can brace it ready for low beam when I'm suddenly pointed at some other car. that way I'm not interrupting my hands. some may prefer one or the other.

you might be able to sort of reverse engineer the event. you know what wires did the welding operation so following those may lead to the problem , in the switch or the high low beam relay.

your high beams take a lot of amps, thick wire , the switch that powers them on or off needs to be able to withstand that amount of amps. I think it' usually done in a way that the high amp circuit is from the battery to the high low relay then to the lights. the wire that goes to the signal light arm is likely a lower amp circuit so that the contacts and wiring dont need to be huge. it likely operates a relay. it may just supply 12V to click the relay into a high or low position.

a pen or a "push on push off" switch both use a similar mechanical arrangement, not such a far fetch to think maybe the high low beam relay has such a mechanical arrangement inside it. If the actual switching was done in the switch arm itself then it would need big thick wires to carry the amps for your high and low beams. I think that's unlikely so I think there is a relay you haven't found yet.

that arm switch could have two wires running it, then two relays one for high beam and the other for low beam and then maybe it would feed 12 V to the coil of one or the other relay. whichever receives the 12V turns on the lights.

above there was mention of a change so maybe they went from two relays to one that gets its first pulse, low beams, a second pulse , high beams, etc.. this can e done with only one wire by way of a special relay that has the mechanics similar to a pen that clicks to open.


there could be a bit more complexity as the headlights lift up and there is some switching in and around that. you probably can't turn the lights on without them being lifted, so maybe there is a contact there that's involved to prevent that situation. the operation of the headlights was described in another thread.

my guess is it's a bad rely and the column switch isn't the issue but its just a stab in the dark.

if you can get into a situation where you can hear the relay then that might help find it. hear any click when they turn on or off? follow the sound? look at the high amp wires feeding the headlights, can you physically follow them back to their source? if the system uses two simple relays maybe you can swap them to troubleshoot if they are the same part?

something is off here, If the origin of the issue was arcing, then the cause is a missing washer? , that doesn't add up in my mind but maybe the welding operation was unrelated?

i think in my 66 volvo it has a relay for high low that is operated by a foot switch but it also has a feature where pulling the signal light turns on the high beams. I think either feeds the relay coil which latches and turns on the lights. Im not sure if the foot switch uses the push on push of device or the relay itself. the floor switch may have such an arrangement ( like in a pen) but I dont think the column switch has that mechanical arrangement built in.



the power normally comes from the relay but the switch on the column activates the coil in the relay if you pull it. I think this is because this flashing ability is a safety feature similar to a horn, it needs to still work with the lights turned off.

I dont think that in normal operation they would run all the amps for your headlights through that column switch.

we never use parking lights here but in Europe its common that people leave parking lights on when parked. often with two wheels on the sidewalk. Here we have wide roads no one uses parking lights for parking. our cars were made to pass safety inspections and some requirements might be different country to country. my 66 Volvo doesn't even have emergency flashers. there was an option kit for adding that. 4 way flashers often share a similar relay to signal lights. In my old ford van I can swap them if the signals have issues. It's just a common 3 pin flasher relay.

I seem to remember when working on my old volvo I found out that it had the pull switch on the signal light lever but it was never used so I connected it and installed a relay for that. I think this wasn't required here so they never used that part of the switch originally. I dont think it was needed to pass inspection in this country. maybe it is now. some others with odd volvos use that switch to turn on the overdrive, mine has a switch on the other side of the column for that but that's a rare switch because most didn't have the overdrive. its kind of fun and different as the overdrive can be operated to change gearing on the highway without touching the shifter. it functions as a 5th gear but with its own electric clutch. some racers make it work in 3rd. so they have a gear between 3 and 4..
I got a busted overdrive from someone that made it work in any gear then bumped the switch and broke the overdrive casting right in half.