starter motor wire

[johnbeck]

Hi all. I think I have either a bad ignition switch or a bad wire to the starter solenoid. Turning the key doesn't activate the starter, but jumping across the solenoid does. What color wire is leaving the starter wire connection on the back of the switch(73 bronco), and does it go totally uninterrupted to the solenoid(and same color wire?)? Any quick check method? Thanks

 

[JAFO]

http://broncograveyard.com/rt-1273-technical-diagrams-archives.html

The quality of the diagrams is poor if you try to zoom them.

This site has a better quality copy...

http://www.broncohq.com/pdf/66-77/wiring/66wiring.pdf

Looks like maybe Black/Orange stripe wire from switch. I installed a Centech harness, so have no idea if the wire colors would match, but expect they would not.

 

[Jdgephar]

Red-blue wire straight from the ignition switch to the starter relay/solenoid. Check for 12V on that wire when the key is in "start".

 

[Crush]

Also check the plug in on the drivers side right behind the valve cover. That is the beutral safety and backup light plug. Make sure it is plugged in and that the red/blue wire is still connected. Tried for days to start mine up after sitting for a couple years. New motor and trans but no start. Finally lookin at a schematic i noticed that the red/blue wire ran through there. Plugged it in and it cranked right up

 

[Broncobowsher]

Do you have an automatic? Could be the neutral safety switch.

 

[DirtDonk]

What they said. Red w/blue for factory and the newer Painless kits, and Violet/Purple for most aftermarket wiring harnesses (using the GM color codes) that you see available.

Also as mentioned, '72 and prior Broncos had that wire running straight from the switch to the relay uninterrupted. Routed through the firewall over on the passenger side.
In '73, when the automatic became an option, the wire would go through the firewall behind the engine, through the NSS connector and either to the switch on an auto-trans equipped Bronco, or connected by a jumper wire there at the connector on manual-trans equipped trucks.

If you do have voltage at the wire as Jdgephar mentioned, then it's likely just a bad relay/solenoid. Don't cheap out here though, as the cheapest ones seem to fail regularly.
Either get an expensive one, or a factory one from a junkyard. Unfortunately, there's no real feedback from the expensive store bought ones yet, as most of us won't spend 50 or 60 bucks or more on a part that's also available for 15 or 20. Until a few more of us go for the big buck options and report back, we don't know what the extra money gets you these days.

Good luck.

Paul

 

[johnbeck]

Much thanks all. My wires at the solenoid had been repaired so I hooked up a hot wire from the battery and poked a ground into the wire(red/blue) all along the way to the switch. Bad ignition switch. What's the best replacement? My Bronco was made 2/73. There is a neutral safety device with wires coming off the trans. but I didn't see any interruption of the starter red/blue wire from switch to the solenoid. Need a switch, then I'm going to look into where the neutral safety wires go.(In 43 years it may have been bypassed). Thanks again for your support. John Beck

 

[Steve83]

This shows how your truck should be wired:



Read the caption.

 

[Boss Hugg]

The red/blue wire will have continuity as long as the shifter is in numeral or park. I have hunted for hours on end for a bad spot in the wire, only to find that a kid playing had pulled the shifter out of park. (Note: never once did I EVER leave it in drive when I got out...�&#56900

 

[johnbeck]

Thanks for the diagram and info on the neutral safety. My next challenge is finding the best replacement ignition replacement switch.