If I pull the yellow ignition wire off the starter relay it will still start with the key. If I leave the yellow wire hooked up to the relay the starter stays engaged. Is this a bad starter relay or is something wired wrong? Just got the car and can tell someone has been in the wiring.

Look at the position of the wires on the relay.

In this picture the yellow wire, that is tilted on the box, is the positive feed from the ignition and should only have positive voltage during cranking.

The brown wire at the bottom is the ground that passes through the park/neutral or clutch safety switch.

Middle wire is the power to the starter relay when cranking and the large at the top is a pass through positive voltage to the dash wiring & feeds the relay to the starter when engaged.

If you remove the ignition wire, yellow in the picture, it shouldn't crank at all.

Is it wired like this?

Take a voltmeter and do the following.

1. Check for positive voltage at the ignition (tilted yellow wire). It should only have positive voltage when cranking.

2. Check for a ground on the ground (brown wire). It should only have a ground when the car is in park/neutral (automatic) or when the clutch is pressed (manual tramsnission).

3. When it is stuck in crank mode check for voltage at the center terminal. It should only have voltage when cranking with the key and in park/neutral or clutch depressed.

If someone has been in the wiring the colors could be different but the position on the relay are the same.

From the factory the ground has a special connector that will not allow it to be connected anywhere else on the relay.

All battery current, voltage and amps, come from the negative side of the battery and returns to the positive post.
Positive to negative current flow only happen internally in all D.C. batteries

How useful

Yellow should only be hot when the key is in the crank position. If it is cranking all the time you either got a bad switch or the yellow is possibly melted into a 12 volt hot source.

Couldn't the relay be at fault?

Joe

Yes it could be, but the factory yellow wire is from the ignition switch.

The op said disconnect the yellow wire and it works normal when it shouldn't work at all.

This leads me to believe the wiring is wrong or the relay has some connection issue.

That is why I specified checking voltage at the wires and if the signal there was the correct polarity.

These old cars will burn the wiring harness and cross wires in a heartbeat.

Check the ignition switch plug and wiring at the connector. I have seen them melted and causing issues.

Try loosening the starter bolts and jiggle it around and then retighten both fasteners to see if that will help

I have seen that work more than once

^^^^
this

The starter works.

Thanks for the replies. Someone added an extra work on the solenoid circuit. Currently tracing it back to see where it goes. Not sure if it is factory or not.

What is this. The wire runs to it.

With a test light ck for battery voltage on the smaller wire at the starter, It should ONLY have voltage with key in start position. If no voltage and starter stays spinning, you have bad starter

If you have voltage in any position besides crank.
Ck voltage at the relay yellow wire. That should only have voltage with key in crank position.

If the voltage on said yellow wire goes away after releasing the key. You have bad relay
If it HAS voltage in any position besides cranking position you have bad wiring between switch and relay

Never saw one of those...
Do you have a picture of the relay & wires?

Mystery wire is unhooked. Still doing it. Reverse lights are on I'm park. Could that be related?

The reverse lights on in park is usually just a shift linkage adjustment or a worn linkage bushing. An out of adjustment situation would prevent it from cranking in park or neutral.

Work through the gears and see if the reverse light stays on.

If so it could be a bad switch or wiring.

Use a test light or voltage meter to check for polarity and power at the wires going to the relay.

1974's had seat belt interlock, that could be what the box is.

Something is keeping the relay picked, test the voltage on the yellow while operating the ign. sw.

Pretty sure the seat belt interlock has a red button to push.