70 coronet no start with ignition key.

[Big bill]

I’m working on a 70 Dodge coronet barn find it won’t start with the ignition key, but it will start with a starter button attached to the starter relay, but nothing with the key and I don’t have a 70 factory service manual any advice or pointers in which way To Go would be appreciated. So far I had to change out the battery cable and the starter relay.

 

[59pwrwgn]

The relay needs to be grounded. Yellow should be hot when key turned to start. Brown wire needs to be ground. This is done by the neutral safety switch in the automatic trans in Park or neutral. Did they put one on the clutch pedal in 70?

 

[PurpleBeeper]

Well, the key is doing “something”. If I understand correctly, you turn the key to “on” and jump the starter relay and it fires up and runs. If you turn the key to “start” it doesn’t crank over (?) or it cranks over but doesn’t fire up & run?
Either way, it sounds like an ignition switch or the wiring going to it. 1st - look for 2 flat multi-connector wire plugs at the very bottom of the steering column by the driver’s feet. Wires often melt right at those plugs. You’ll be focusing on the slightly larger of the two plugs with the slightly larger wires….red, black, blue and 2-3 more. Look right at the plug area. 2nd guess…the ignition switch inside the steering column (hard to get to)

 

[PurpleBeeper]

The relay needs to be grounded. Yellow should be hot when key turned to start. Brown wire needs to be ground. This is done by the neutral safety switch in the automatic trans in Park or neutral. Did they put one on the clutch pedal in 70?

Yep 70 only “clutch neutral safety switch”

 

[Big bill]

It’s an automatic, and I checked the neutral safety switch and ran a quick jumper ground, and that didn’t seem to change anything.

 

[Rockland71GTX]

Service Manuals – MyMopar

 

[R413]

It could be as simple as a bad starter relay.


Sometimes it is loose connections inside the bulkhead connector. Wiggle the engine harness connector.

 

[59pwrwgn]

Make sure all your contacts on the relay and wire ends are clean. I had an intermittent problem last year that was solved by cleaning.
When you say jumped. What posts on the relay were you jumping.
The relay case needs to be grounded to the body. The brown? Neutral safety needs to be grounded. The the yellow wire? Should be 12 volts with the key turned to start.
Do you have a test light or volt/ohm meter to test.
If not, and you think the relay is wired correctly. Put the car in Park and jump the I assume yellow wire post with 12 volts. If it turns over you will need to check the wiring back towards the ignition switch and maybe the switch itself.
Down load the manual and look at the wire diagram for your car for routing and wire colors

 

[Big bill]

I disconnected the neutral safety switch wire, going to the transmission and put a jumper on that terminal to the body , the wiring under the dash looks excellent I will investigate some more today thank you guys for all of your input help.

 

[Big bill]

The electronic ignition wiring was all burned up when I got the car I put a new harness on and wired it correctly. Check the balance resistor. It didn’t have a coil so I added that as well.

 

[70 sublime]

Is there power getting to the key as in other things work when you turn the key but just will not trip it to crank the engine over ?

 

[Big bill]

I did not check , the lights do work .

 

[70 sublime]

If you can by pass the key and get the engine to crank and start with a button on the relay but still need the key on to make the ignition part work you just have one wire giving you problems that goes to the relay

Try wiggling the key as you turn it to see if things are crudded up or worn and see if that makes any difference

 

[Big bill]

Well, **** dogs I made a dedicated ground jumper for the neutral safety and she turns over with the key yippee but I want to thank everybody for all their input and their help very knowledgeable stuff. I learned a couple things along the way thanks everybody on b bodies.