Headlamp Switch

RCHunt · Aug 5th, 2023, 13:32

Volvo 142 Rally Car. Headlamp main beam switch has stopped working correctly. The headlamp flasher still works but the headlamps will not switch onto main beam instead of the lever "clicking" into place the lamps appear to go out while the lever is held. Could this be a fault with the switch or the relay?

142 Guy · Aug 6th, 2023, 19:46

Your description is a bit confusing.

Do the dipped beams work normally? If so, that means the switch on the dashboard is working correctly. Your latching headlight relay may or may not be OK.

My 1971 North American spec car has the flash to pass function - pull the turn signal lever toward you briefly and the high beams will flash even with the dash headlight switch off. If the flash to pass function works (main beams flash); but, the problem is that the main beam lights will not come on and stay on then the problem is most likely the steering column switch. Go here to Ron K's website and find the wiring diagram for the 140.
https://sw-em.com/Wiring_Diagrams_an...iring_Diagrams

Object #26 is the steering column switch and shows the contacts for the turn signals and the main beam control. The white wire is the main beam control. Disconnect the white wire from the switch and connect a continuity tester between that terminal on the switch and chassis ground. It should indicate open circuit in the resting position. Do the flash to pass function and you should see a momentary closed circuit. Pull the lever toward you to switch main beams on continuously and you should see a continuous closed circuit. Failure of any of those conditions indicates a failed steering column switch.

RCHunt · Aug 7th, 2023, 16:05

Amazing what sleeping on a problem can do. The car hasn't had a proper run for a while but I have spent quite a lot of time chasing various electrical problems. The answer? Not enough battery charge. Needed a jump start, ran the engine for a minute or two and everything's fine.
Sorry to ask you to help sort out a problem that was really very easy.

142 Guy · Aug 7th, 2023, 17:10

If the battery had lost enough charge that it was not able to pull in and latch the headlight relay your next electrical demon may be replacing the battery. Lead acid batteries don't take kindly to being left in a state of discharge. You may have been able to jump start the car and you may be able to get it to restart; but, in a couple of days do not be surprised if you come out to find that it is dead again.

Aug 5th, 2023, 13:32	#1
RCHunt New Member Last Online: Apr 14th, 2024 19:26 Join Date: Mar 2022 Location: Seaton	Headlamp Switch Volvo 142 Rally Car. Headlamp main beam switch has stopped working correctly. The headlamp flasher still works but the headlamps will not switch onto main beam instead of the lever "clicking" into place the lamps appear to go out while the lever is held. Could this be a fault with the switch or the relay?

Aug 6th, 2023, 19:46	#2
142 Guy Master Member Last Online: Today 15:46 Join Date: Jul 2020 Location: Saskatchewan, Canada	Your description is a bit confusing. Do the dipped beams work normally? If so, that means the switch on the dashboard is working correctly. Your latching headlight relay may or may not be OK. My 1971 North American spec car has the flash to pass function - pull the turn signal lever toward you briefly and the high beams will flash even with the dash headlight switch off. If the flash to pass function works (main beams flash); but, the problem is that the main beam lights will not come on and stay on then the problem is most likely the steering column switch. Go here to Ron K's website and find the wiring diagram for the 140. https://sw-em.com/Wiring_Diagrams_an...iring_Diagrams Object #26 is the steering column switch and shows the contacts for the turn signals and the main beam control. The white wire is the main beam control. Disconnect the white wire from the switch and connect a continuity tester between that terminal on the switch and chassis ground. It should indicate open circuit in the resting position. Do the flash to pass function and you should see a momentary closed circuit. Pull the lever toward you to switch main beams on continuously and you should see a continuous closed circuit. Failure of any of those conditions indicates a failed steering column switch.

Aug 7th, 2023, 16:05	#3
RCHunt New Member Last Online: Apr 14th, 2024 19:26 Join Date: Mar 2022 Location: Seaton	Amazing what sleeping on a problem can do. The car hasn't had a proper run for a while but I have spent quite a lot of time chasing various electrical problems. The answer? Not enough battery charge. Needed a jump start, ran the engine for a minute or two and everything's fine. Sorry to ask you to help sort out a problem that was really very easy.

Aug 7th, 2023, 17:10	#4
142 Guy Master Member Last Online: Today 15:46 Join Date: Jul 2020 Location: Saskatchewan, Canada	If the battery had lost enough charge that it was not able to pull in and latch the headlight relay your next electrical demon may be replacing the battery. Lead acid batteries don't take kindly to being left in a state of discharge. You may have been able to jump start the car and you may be able to get it to restart; but, in a couple of days do not be surprised if you come out to find that it is dead again.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)