27-03-2023, 04:00 PM
While chasing a problem on a friends 1974 bus we came across a gotcha if using the Samba Wiring Diagram or any that shows US wiring.
Trying to rush I didnt remove the fuse box as it is behind a dash tray so was working from the dash panel end, and questioning what I was missing as the light would work on flash.
As you probably know the diagrams are from an US source and the wiring of the headlight relay is only 4 pin, not 5. The 5th is to allow the high beam to flash without the ignition on. Pin 30. So if you are tracing a fault where the lights will flash but no lights with the switch and ignition on, it is likely the relay has burnt contacts on the ignition/light switch controlled side. The check is to pull out the fuse box and test the white/black at the relay on the back of the fuse box is live when ignition and lights switch is on and power on the top of fuses S3&4 or S5&6 when you switch high/low beam. Dead at one or both of the outputs 56a and 56b (one working at a time) means you have an issue. The relay should make noise regardless with ignition on or off if working properly.
E1 is the headlight switch and J is the relay. 30 on the 5 pin relay would be from an unswitched 12v source, but I have to locate it. Just be aware it is there.
On the example pic below it shows the 30 pin and on some sites it shows the mod for earlier busses to link 56 and 30. I am fairly certain that isnt the way it is done in the original install as you would need the ignition and the light switch on to flash which isn't the idea for it.
In the diagram (the Samba US one)you can see that the coil is supplied from 56 which would mean it doesnt operated unless the ignition and headlight switch are on.
Adrian
Trying to rush I didnt remove the fuse box as it is behind a dash tray so was working from the dash panel end, and questioning what I was missing as the light would work on flash.
As you probably know the diagrams are from an US source and the wiring of the headlight relay is only 4 pin, not 5. The 5th is to allow the high beam to flash without the ignition on. Pin 30. So if you are tracing a fault where the lights will flash but no lights with the switch and ignition on, it is likely the relay has burnt contacts on the ignition/light switch controlled side. The check is to pull out the fuse box and test the white/black at the relay on the back of the fuse box is live when ignition and lights switch is on and power on the top of fuses S3&4 or S5&6 when you switch high/low beam. Dead at one or both of the outputs 56a and 56b (one working at a time) means you have an issue. The relay should make noise regardless with ignition on or off if working properly.
E1 is the headlight switch and J is the relay. 30 on the 5 pin relay would be from an unswitched 12v source, but I have to locate it. Just be aware it is there.
On the example pic below it shows the 30 pin and on some sites it shows the mod for earlier busses to link 56 and 30. I am fairly certain that isnt the way it is done in the original install as you would need the ignition and the light switch on to flash which isn't the idea for it.
In the diagram (the Samba US one)you can see that the coil is supplied from 56 which would mean it doesnt operated unless the ignition and headlight switch are on.
Adrian
A new beginning. 
+
1975 Kombi The Doctor
1976 Dual Cab Bumble Bee
1974 Microbus Matilda (parts bus)
+1975 Kombi The Doctor
1976 Dual Cab Bumble Bee
1974 Microbus Matilda (parts bus)