Starter won’t turn help please!

[Pbotz]

Ok so I am having an electrical issue I’m out of luck with.

1973 Ford Bronco. Story goes I had an issue with the turn signal fuse always blowing. Stupid me put a larger fuse, way more than was supposed to go in there to keep it from blowing. Well went to start it and drove around and started having smoke and burnt electrical coming from under the dash. Immediately shut car off. Got her back home only to realize that the back up lights, which are also part of the turn signal switch were unplugged and were grounding out on the valve cover. The fuse held but the wiring didn’t. Now my bronco won’t turn over. All accessories work when the key is in the on position, but I can’t get it to turn.

So far i have tested the starter solenoid by jumping it, which turns the starter and starts the car, however I have no power coming in from the blue/red wire when attempting to turn the car over. I assumed it was the ignition switch, purchased a new one, still no start and no power to the red/blue wire when attempting to turn vehicle over.

I replaced the fusible link that connect to the starter relay to no avail.

I have an MSD ignition so no ICM, so I don’t think there would be any diagnosis there.

im wondering, is there two Separate power sources at the ignition switch, one that powers accessories, which all work, and a separate circuit dedicated gage the starter relay?
I have looked at the wiring diagrams and see a yellow wire that seems to power the ifnition switch?

I have looked at the wiring diagrams and am wondering if I fried wiring at the ammeter behind the cluster?

Any help would be appreciated. I am at a loss, the usual culprits seem to be working but why no power from my ignition switch to starter relay, but power to all accessories in start position?

 

[DirtDonk]

Because you have a 73, you have the wiring harness for the neutral safety switch, whether you have an automatic or manual transmission.
Somewhere behind the engine near the other wires will be a 4-wire plug that carries the red with blue stripe wires.
For an automatic transmission it goes down to the neutral safety switch. For a manual transmission, there is a jumper wire there instead
If the jumper wire has failed for whatever reason, the vehicle won’t start. Same with a neutral safety switch.
But whether you have a manual or auto, you can test for electricity at that plug.
Separate the two halves and , with somebody turning the key to start, check for voltage on both of the red w/blue wires in the connector.

Yes, the yellow wire feeds the ignition switch.
And yes, there are separate functions on the switch for each circuit.
The black with green stripe wire coming out of the center of the switch is for all the normal accessories that work in the ACC and 0N positions.
The red with green and green with red wires are on the same terminal in the ignition switch and work the ignition coil and voltage regulator in the ON position only.
The red with blue wire is its own circuit and it’s only function is to get the starter cranking.

So I guess really the next step is to just find that neutral, safety switch plug and test for power there.

 

[DirtDonk]

Oh, don’t throw away your old switch. Just in case it’s still good since it seems that the new one is doing the same thing.
The problem is new parts aren’t always perfect.

Hard to say what else the burned turn signal wire might have taken out with it. For now we’re hoping that the reason the starter isn’t turning is simply a coincidental failure.
But you’re going to need to follow the wires around look for damage and ancillary damage.
You’re gonna have to follow the smoke…

 

[ba123]

that sucks!!! fuses blow for a reason though. Hope it works out to be not too bad and that you learned never to do that again.

I would isolate the entire lighting system that ties into the turn/brake/reverse lights. they all go through that switch, so disconnect them all and then troubleshoot.

 

[Pbotz]

Ah! Thanks @DirtDonk!

So the reverse light switch that I pulled did indeed have a looped wire under all the burnt tape. Didn’t think I had a neutral safety cause it’s 3 on da T…. ASSumed again…. Lol

Surprisingly it didn’t melt with the reverse lights. I didn’t even know it was there. Cut out the burnt wires I fried. Fired right up…. My gauge cluster lights no longer work and I had to jump my Bronco, so I might have screwed the alternator regulator when it shorted, in addition to other lighting circuits, but at least I don’t have to start with the hood open and a screwdriver. Thanks a lot again guys much appreciated.

 

[DirtDonk]

The voltage regulator might still be working. You have to test the voltage with the engine running. Should read about 14.5 V at the battery.

You were correct that you don’t have a neutral safety switch with your manual transmission.
But you do have the circuit for it, because Ford only installed one wire harness in all Broncos, and all they had to do was connect it if the automatic transmission option was chosen.
That’s what that jumper loop is for. To take the place of the neutral safety switch, as a bypass.

The same connector handles the back up lamps. Because with an automatic, the neutral safety switch handles the back up lamp duties as well.

 

[Pbotz]

Thanks again @DirtDonk and @ba123

Yes I’m getting good voltage so phew on that! I think actually the fan blew smoke from the engine compartment into under the dash since I have some really old grommets. I think for the most part however the wiring is good.

The wiring schematics that were posted are really helpful too. Whoever did that props from all us newbs!

 

[m_m70]

Well went to start it and drove around and started having smoke and burnt electrical coming from under the dash.

well that would be enough for me to go through everything behind the dash. smoke and burnt electrical coming from under the dash is not a "warning" something is about to go wrong, it means something has already gone wrong. no fun but but a have to in my book.

fuses blow for a reason though

wise words right there. fire is no fun.