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Another Ignition Question

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dart6

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20190115_194902_resized.jpg

My 70RR doesn't seem to be getting power to the ign nor the starter

The big red wire on the starter relay has constant power with key on or off as well as the fusible link. The big brown wire has no power when the key is turned fully.
The starter works when i short the brown and red on the relay
With a testing light the coil or ballast don't seem to get power with the key on.
Outer connector block is new, don't know about the interior one. Wires in engine bay are new as well as the ignition switch

Before this happened i pulled the fuel tank because the new sender was barely reading at all. I removed the sender, attached longer wires to how it was in the tank so i could watch the gauge as i moved it. When i did that it was reading all over the place and then just goes to far right. I gave up and installed sender back in tank and tank in car.
When key is on it goes straight to the far right.
I don't see a connection but thought i should mention it 20190115_194902_resized.jpg
 
Yellow wire feeds from the key to energize the starter relay. It will only function if the black wire that attaches to the relay is grounded by the neutral safety switch at the trans. The fuel outlet tube at the tank must be grounded for the gauge to function. You can test the rest of the circuit easily. Unplug the sender. Ground a test light and insert it into the sender wire. The light may blink. Gauge should read about 1/2 full. If so its either the sender or a bad ground.
Doug
 
The sender is bad i know i just mentioned it as something i'd done before the starter/ ignition woes.
The wire [brown/yellow] next to the yellow and below the fuseable link is the middle wire at the neutral safety switch.
dvw said:
Yellow wire feeds from the key to energize the starter relay. It will only function if the black wire that attaches to the relay is grounded by the neutral safety switch at the trans.
Click to expand...
How would i go about testing that
 
Have someone hold the key in the crank position. Test the yellow wire with a test light with the aligator clip connected to ground. It should light in the crank position only. Connect the test lamp aligator clip to batttery positive. Probe the black wire with the test light. It should light without touching the key in both park and neutral only. Let me know the results .
Doug
 
Yellow has no power when key is at crank. The black wire you refer to is actually brown/yellow on mine and it lights up at both park and neutral only
 
Last edited:
The yellow wire should have power when the Key is in the start position.
It appears the neutral safety switch is good.
 
dart6 said:
Yellow has no power when key is at crank. The black wire you refer to is actually brown/yellow on mine and it lights up at both park and neutral only
Click to expand...
So now we have to back track. The yellow wire feeds from the ignition switch. It comes thru the firewall at the bulkhead. I'm assuming when the key is turned to run items like the radio, dash etc have power. If so I'd start by checking the firewall connector. Not uncommon to see corosion or melting at the bulkhead. The starter relay can be tested by powering the terminal for the yellow wire with battery positive. Since you have already found an issue with that feed circuit my bet is the relay is OK.
Doug
 
I'll drop the steering column and check the connections.
I think the starter relay is ok too
 
Ok i found a pic of the connector and can see how they separate. I've separated them and sprayed with deoxit so will let it sit a while.
 
dart6 said:
The big brown wire has no power when the key is turned fully.
The starter works when i short the brown and red on the relay
Click to expand...
Just remembering the relay wiring on my 64. Red is from battery, so hot all the time. Brown wire, on mine, goes to starter, only gets current when key is on start.
If brown gets current, when you short it, only, is what made me think the relay. Or, it's in the wiring to it. Test light to the brown, key at start, will tell.
Good luck on it!
 
[QUOTE="miller, post: 911155079,
If brown gets current, when you short it, only, is what made me think the relay. Or, it's in the wiring to it. Test light to the brown, key at start, will tell.
Good luck on it![/QUOTE]

. As long as the neutral safety circuit is grounded the relay will be energized by the yellow wire when the key is in crank only. When energised, the relay connects the brown solonoid wire to the red feed wire.
Doug
 
dart6 said:
Yellow has no power when key is at crank.
Click to expand...
Is this still the case? Hate trying to remember, but doesn't it feed from the ignition switch? Or, losing current at the firewall connection.
 
Well last night it wouldn't crank but after a couple of minutes it did start. Tried again this morning and it wouldn't crank
 
dart6 said:
Outer connector block is new, don't know about the interior one. Wires in engine bay are new as well as the ignition switch
Click to expand...
Engine bay wiring, ignition switch new. Okay.
Flaky current feed to relay, yellow wire. Could be looking at yellow wire, under the dash, bad, or connection at either end. Check it, by pulling the yellow wire off the relay, un-hook the ignition switch connector, so you can get to both ends of that yellow wire. Ohm check it...should be a 0, or real close.
Might have to look at the connection in the firewall block, to see if it's good.
 
miller said:
Anything??
Click to expand...
I've been tied up. I used a multimeter for ohms but the leads weren't long enough so i used an extra wire with alligator clips, not ideal i know. I measured from the B/head to the connector [seperated] that attaches to the key wiring and got from miniscule to no resistance.
Anyway i would like to do the same test with a power probe i managed to get a hold off

I want to be certain here. I'm guessing that circuit would be + when working correctly aye.
My thinking is, if a send a positive charge through it with the probe and the car cranks/starts then i look at the wiring in the column
 
dvw said:
Have someone hold the key in the crank position. Test the yellow wire with a test light with the aligator clip connected to ground. It should light in the crank position only. Connect the test lamp aligator clip to batttery positive.
Click to expand...
Just as Doug said.
Should be straight from ignition switch, through the firewall block, to the starter relay. That's why I mentioned pulling the connections for the yellow wire, at both the relay and switch. Wire sounds good, but checking from end to end, would have shown if there's a poor connection, at the firewall, or somewhere else. Ignition switch...all of it new, or just the key part? Might check the yellow wire connection on the switch, to be sure it's not loose.
But, as Doug said, just as easy to check for power at the relay end, via the yellow wire, ignition at start.

Aw crap! 70RR, ignition switch is probably in the column.

Too many simple things, can kill the circuit, that's causing the problem. A loose connector, corrosion, so on...just have to find it.
 
Last edited:
My job is debugging electrical/computer issues on prototype vehicles at the Chrysler engineering center. Many times we'll send power thru a circuit to verify its integrity. I normally use a late model headlamp bulb as it takes a few amps to illuminate. Power up one end of the circuit, ground the other. My bet is there are 3 area's that would be the most likely suspect. The Firewall connection, The connector at the ignition switch to the dash harness, The switch itself.
Doug
 
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