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Headlight switch testing

Discussion in 'Fuel System & Electrics' started by Ian and Shelley, Nov 30, 2018.

  1. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Hi..

    I am needing some advice about testing my headlight switch.

    Headlights don't work..
    Headlights work when flashed from stalk.

    Headlight switch when pulled turns on dashboard lights and relay clicks.

    To prove if the switch is working correctly should I be able to measure 12v from the wires connected to the headlight switch?

    If no Volts is switch broken or could there be other issues

    Any advice most welcome

    Thanks Ian
     
  2. Grantus

    Grantus Well-Known Member

    Messages:
    14,738
    Location:
    Southern ACT
    Ignition switch is faulty........;)
     
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  3. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Thanks

    I ordered one of those just in case, will replace tonight and see how we go.

    Thanks
     
  4. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,042
    Location:
    Avalon Beach NSW
    Ignition switch x 2....as previously advised.
    Let us know how it goes.
    Cheers,
    Mark
     
  5. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Hi all

    New ignition switch installed and still....No lights

    I have 12 Volta going to switch and 12 Volta coming out switch when ignition turned on..

    Tracing B/ W wire to fuse and lights...

    Any advice most welcome
     
  6. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Quick check and ZERO Volta at fuses 1,2,3,4,5. Which I believe are all light fuses....

    So no.power to fuse box......
     
  7. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,705
    Location:
    Penna, Hobart
    In at least the early to mid bays there is 1 and 2 that are fed from the light switch and 3,4,5,and 6 that come off the ignition. If you don't have a wiring diagram this is going to be difficult. It isnt a case of one side is the feed bus and the other is the load.

    What year are you and I will try to track one down for you.

    Adrian
     
  8. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Thanks...

    Electrics not my strong point my as you can see...

    I have a 1975 bay
     
  9. cbus

    cbus Well-Known Member

    Messages:
    10,921
    Location:
    sunshine coast
    So no headlights when passing switch activated ( lever held up) ?
     
  10. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach

    Light come on when lever held up

    That's the only time they come on..

    I have replaced new ignition switch and new headlight relay..

    How can I by-pass the pull switch to eliminate switch problem..
     
  11. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,042
    Location:
    Avalon Beach NSW
    Please don’t miss understand this......
    but you do have the ignition switch turned on when you are checking the lights, don’t you?
    Cheers,
    Mark
     
  12. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Yes.

    Ignition on when testing.lights..

    With ignition on dashboard lights come on but No headlights or rear lights when light switch pulled
     
  13. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,042
    Location:
    Avalon Beach NSW
    Pull the fuses and check them very closely.....sometimes the blown fuse still looks complete but there’ll be a small break in the metal itself.
    Worth checking the headlight bulbs too....
    Cheers,
    Mark
     
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  14. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,705
    Location:
    Penna, Hobart
    bus-73-75.jpg

    Although this looks daunting, the colours will help a lot. The small numbers such as 4.0 and 1.5 are cable sizes larger is bigger.

    In the case of switches such as D there are parallel thin black lines running across the page between diagonal thicker black lines. They are not an electrical connection, they mean that the contacts on that line all open and close together. The other thin lines are electrical connections meaning they are connected inside the switch/instrument/relay with a bus bar or similar but you probably wont be able to see them(but you can test for a connection with a meter).

    The T letters are just connectors but some are in a connector block together. Their locations are in the legend.

    The little number in circles that are orange are test points and they correspond to the test socket pins on the top right of the engine bay.

    Most important is look at it logically and take it step by step. The fuses themselves are the S labels and as you will see they are all over the place with some switched through the ignition.

    The last thing is the bottom yellow line is earth or negative. Make sure you check the earths on the headlights, under the middle of the dash on the front panel and also on the back of the headlight buckets behind the kick panels (if I remember correctly) as well as either side of the engine bay inboard of the tail lights. You get weird things happening with a bit of corrosion on the connectors. As Oldman said, take out the fuses and make sure the contacts are clean as well as the elements aren't fractured too.

    Good luck

    Adrian
     
    Last edited: Nov 30, 2018
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  15. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Thanks Adrian...

    I will get straight onto it this afternoon and hope for more success today..

    Thanks for all the help
     
  16. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Replaced all fuses, cleaned All terminals, checked earth all good and no change..

    I still have ZERO V to fuses 1-6 when lights turned on and.Ignition on...

    How can I bypass the switch to see if switch faulty?

    Or bypass the relay to check if new relay faulty?
     
  17. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Hi all

    Stupid question number 13...


    Should there be a wire on the spare connector on my headlight switch?
    As in photo..

    With ignition and switch on I get Volt reading from big red wire small red / grey wire and black with thin white stripe wire..

    The white with black and grey wire give ZERO Volts.

    ARE any of those readings telling me anything
     

    Attached Files:

  18. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,705
    Location:
    Penna, Hobart
    OK, Pictures can speak a thousand words. First you need to swap the black and yellow with the grey and see what happens. I reckon that will make a big difference. There is nothing on the spare terminal, and thank you for prompting me to pull mine out, as the black and yellow connector on mine was loose and starting to arc (connector had discoloured badly).

    In the diagram it says J is the dimmer relay but it is actually the headlight high beam relay. Makes sense when you see the way it is connected. (couple of other interesting labels in there too) The grey and red wire is the instrument lights and the grey is the park lights, the white and black is the feed to the head light relay, the black and yellow is from the ignition switch. The red comes from the fuse box on fuse S8 which is connected internally to S9 fuse. I suspect that red is always on and feeds the parking lights when in park position.

    Remember there is 3 positions for the light switch and it turns to adjust the instrument lighting level. Also remember if the switch is in any position but off the park lights are on, with or without the ignition on. Often left the lights on and turned off the ignition which kills the headlights and then not noticed the parking lights are still on.

    Adrian
     
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  19. Ian and Shelley

    Ian and Shelley Member

    Messages:
    83
    Location:
    Umina Beach
    Thanks Adrian..

    TinTop earlier today suggested I swapped the grey and B/ Y but sadly no immediate fix.........
    BUT we now have power to fuses 1 and 2 and The switch is now giving Volt readings when pulled to all terminals...

    Could wrong grey / B/Y have damaged relay?
     
    Last edited: Dec 1, 2018
  20. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,705
    Location:
    Penna, Hobart
    Here is the readings for all settings on the switch.

    Ign Off Switch Off:
    12 v on red only

    Ign On Switch Off:
    12v on red and black yellow

    Ign Off Switch On Park:
    12v on red, grey and grey/red (voltage on grey red can change with the position of the dimmer)

    Ign On Switch On Park:
    12 v on red, grey grey/red and black/yellow

    Ign Off Switch On Full:
    12v on red, grey, grey/red and black/yellow (same as above)

    Ign On Switch On Full:
    12v on red, grey, grey/red, black/yellow and white black.

    OK, so now if you have S1 and S2 with power that means the parking lights should be on. With the headlights switch on fully you should be able to detect voltage on S3 and 3 and 4 or 5 and 6.(i think 3 and 4 are low beam).

    If the lights work on the high beam with the dip switch pulled up, there must be another feed to them which isn't shown in the diagram. There are quite a few differences I am finding as they seem to be american diagrams. The one below are german (how are you at translating?) and show a power feed independent of the switch which will give you the high beam flash via the dip switch.

    Ill put the last pic in the next post.

    Anyway, it is possible the relay may have failed but not likely with the crossed wires.

    Adrian


    Type_2_-1800_from_August_1973-1.jpg Type_2_-1800_from_August_1973-2.jpg Type_2_-1800_from_August_1973-3.jpg View attachment 43058 View attachment 43059 View attachment 43060
     
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