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914World.com _ 914World Garage _ Head light question?
Posted by: sweathappens Nov 16 2018, 11:35 AM
Hey!
I’m finally getting around to fixing my 74 914 and I am having a problem with my headlights. They don’t work. When I pull the high beam switch on the steering wheel the lights momentarily come on. when I release the switch they go off. I crunched my right front fender which probably shorted out the lights and this is I think where the problem started. I fixed the fender and replaced the lights they all work except the headlights. If you have any opinion on how I should go about fixing my lights I would really appreciate your help. I suspect that the high beam low beam turn signal switch and/or the relay foot fryer during the crunch. I have other problems that I will be diving into after I get this one solved.
Posted by: morgan_harwell Nov 16 2018, 12:01 PM
I have the same issue with my high-beams since I bought my '73 914 back in 1986. The low-beams have always worked fine.
When I pull the switch stalk back to engage the high-beams, the high-beams turn on.
But when I release the switch stalk, the head lights shut off 
No low or high beams, just dark. Quite shocking on the mountain twisties around here !
When I pull the switch stalk back again, the low-beams turn on again, thankfully.
And stay on when I release the switch stalk.
Replacing the steering column switch and the high-low relay did not fix or change the problem.
For the OP & I, any suggestions would be greatly appreciated.
Posted by: Dave_Darling Nov 16 2018, 04:53 PM
Strange, both of those sound like problems with the high/low relay.
The relay will connect an input to one of two outputs. When its trigger wire is grounded, it changes which output the power gets connected do. To do that you have a small electromagnet and a switch (spring-loaded?) that the electromagnet controls.
Anyway, verify the inputs to the relay, then verify the outputs. Make sure that the input terminal (check the wiring diagrams) gets +12V when the headlights are on, and make sure the trigger contact gets grounded when you pull the turn signal switch back. Then check the outputs; make sure that the connection of the input to the low-beam circuit is made and that it changes to connecting the input to the high-beam output when the trigger gets grounded.
--DD
Posted by: sweathappens Nov 16 2018, 07:35 PM
Strange, both of those sound like problems with the high/low relay.
The relay will connect an input to one of two outputs. When its trigger wire is grounded, it changes which output the power gets connected do. To do that you have a small electromagnet and a switch (spring-loaded?) that the electromagnet controls.
Anyway, verify the inputs to the relay, then verify the outputs. Make sure that the input terminal (check the wiring diagrams) gets +12V when the headlights are on, and make sure the trigger contact gets grounded when you pull the turn signal switch back. Then check the outputs; make sure that the connection of the input to the low-beam circuit is made and that it changes to connecting the input to the high-beam output when the trigger gets grounded.
--DD
Thanks for the heads up. Can a the short that was caused by the accident blow the relay? It was working fine before.
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