HELP: Headlight switch triggering STARTER!!!
One of the fuses is for power to the headlight switch B2 terminal. If the parking lights work, then there is power flowing through that fuse.
If you don't know (because of the emergency type situation that occured), take a voltmeter set on DC volts. Place the black probe on a good known ground and the red probe on each side of the fuse. It should show battery voltage.
Power to the instrument lights comes out of the headlights switch and goes back to the fuse box. It connects to 2 amp or for '74 probably 3 amp fuse. On at least some years thats a tan wire from the switch and an orange wire out to the instument cluster. It also goes to the radio light. With the headlight switch in the first position out, there should be voltage there as well. Depending on the rheostat setting it may be less than battery IF current is flowing through it.
So most likely somehow power is getting to the wire going between the key switch and the relay.
When the key is in the start position, current can flow from the wire into the key to the Start (usually yellow) and the Ignition Start (usually brown) wires.
As mentioned above, '74 has a seatbelt interlock that adds a layer of complexity to this, but otherwise works the same way.
Find the wire(s) connecting to the relay and see if its getting power whern the headlight switch is pulled on. If so, then why.
You should be able to do this with a multimeter set for resistance.
Disconnect the battery at the neg post. Then the positive post.
Put the headlight switch in the position that causes the starter to engage.
Place one probe on the battery feed line - the big stud on the relay or the disconnected battery terminal are easy locations to do that.
Place the other probe on the wire connector on the relay.
Early ones look like this. Not sure if '74 has additional terminal.
What connectors? Do you mean the bulb holders?
The first is understandable. A ground from the dimmer switch would be for what purpose?
Not sure what access is like on your, but you can at least begin to trace the circuit from its source.
One of the fuses is for power to the headlight switch B2 terminal. If the parking lights work, then there is power flowing through that fuse.
If you don't know (because of the emergency type situation that occured), take a voltmeter set on DC volts. Place the black probe on a good known ground and the red probe on each side of the fuse. It should show battery voltage.
Power to the instrument lights comes out of the headlights switch and goes back to the fuse box. It connects to 2 amp or for '74 probably 3 amp fuse. On at least some years thats a tan wire from the switch and an orange wire out to the instument cluster. It also goes to the radio light. With the headlight switch in the first position out, there should be voltage there as well. Depending on the rheostat setting it may be less than battery IF current is flowing through it.
Key one position rotated clockwise is RUN. (It might feel like two positions clockwise if as I recall there is a steering wheel lock.)
The starter gets power from the battery when the starter relay closes.
So most likely somehow power is getting to the wire going between the key switch and the relay.
When the key is in the start position, current can flow from the wire into the key to the Start (usually yellow) and the Ignition Start (usually brown) wires.
As mentioned above, '74 has a seatbelt interlock that adds a layer of complexity to this, but otherwise works the same way.
Find the wire(s) connecting to the relay and see if its getting power whern the headlight switch is pulled on. If so, then why.
You should be able to do this with a multimeter set for resistance.
Disconnect the battery at the neg post. Then the positive post.
Put the headlight switch in the position that causes the starter to engage.
Place one probe on the battery feed line - the big stud on the relay or the disconnected battery terminal are easy locations to do that.
Place the other probe on the wire connector on the relay.
Early ones look like this. Not sure if '74 has additional terminal.
What would this do?
