No Crank Issue

[SpeedThrills]

I’ve been trying to wrap up my project car, a 1974 Dart Sport. Cloned it into a 1971 Duster.
As of a couple days ago, it cranked and started. Yesterday, I was welding in tail light brackets and forgot to disconnect the battery. Now it won’t crank. I can jump the relay, and with the key on, it starts. Previously I did the Mad Electric ammeter bypass. The fusible links to and from the relay have continuity.
This car has that damned seatbelt interlock. It has the white plastic box up under the dash, near the fuse block. However, it does not have the gizmo under the hood that has the bypass button on it. It does have what I show here in the picture. I’ve never seen this set up before, so I don’t know what this is. The gizmo in the picture clicks when I turn the key to start.
Did I fry the interlock? How do I find out? If I shoot the car, will I feel better?

 

[67Dart273]

You need to bypass that interlock. Find the two yellow wires going to the connector and permanently jumper/ splice them together. Those yellows are the wire to the start relay, and it "breaks" that circuit. However that one does not look "right." Does it have a reset button? Might be "something else" smog control?

 

[67Dart273]

That which you pictured does not look right. It does not have typical "period" Mopar connectors. Are you sure that isn't part of a security system, etc?

 

[SpeedThrills]

That which you pictured does not look right. It does not have typical "period" Mopar connectors. Are you sure that isn't part of a security system, etc?

It’s part of it, I don’t know what it is. When I bought the car, it had no evidence of fiddling. Was all original. The ground wire under the bolt is for my line lock. A couple years ago, you helped me with a no start on this car and you mentioned the button thing and I’ve read a lot since then.
Anyhow, looking at it more closely to take additional pictures, I noticed one of the connectors wasn’t plugged in correctly. Was probably sitting like that for a couple years and was making “just good enough” contact. (It’s been sitting in the garage.) Problem solved. An easy one!
I’m including more pictures to show you what this thing looks like. I don’t see any numbers on it.

Q

 

[67Dart273]

Something is not right there. There is no reset button, that is not the seat belt interlock device. Do you have a gearbox with electrical connections inline in the speedo cable?

You might do some troubleshooting. See if any of those wires "come alive" in the start position of the key. Then see if one of them shows continuity with the yellow going to the start relay. Disconnect both ends and check

 

[SpeedThrills]

All I can say is the loose connection fixed it immediately. No gearbox on the speedo.
There is no other unknown device under the hood. I’ve had the whole car apart.
There is only one yellow wire, and that has a black tracer.
I’ll look into it more when I have time.
Thanks for pointing me in that direction. The wire looked like it was connected, but…