are the 2 juntion box terminals both neg?

[fordfrank]

Hi gents,
If you saw my earlier post you know I'm working trying to start my 31 for the first time and I'm wrestling with the wiring and power flow. I'm not getting any spark at the plugs and have been working the wiring to trace from the battery where the breakdown occurs. This is all new to me so I'm trying to figure this out as I go along. I've got a decent wiring diagram now and that's helped a lot.
Here's where I'm at - I have neg power to one of the terminals on the junction box but nothing on the other. My amateur read of the diagram leads me to think I should have neg power to both terminals. The first straight from the cable off the starter and the second from the return cable off the ammeter. Is that correct? Should both those terminals have neg power? or only one? I don't see how that generator can recharge the battery unless you have a neg circuit that runs all the way from the battery to the relay on the generator.
I know I have neg flowing into the ammeter but should I have neg coming out the other side and then back to the second terminal on the j-box?
Oh, by the way, just found that my ammeter is bad and wires behind it all crapped up. Can I just hook those wires together and get the same effect on the ignition system? Does the ammeter do anything more than give me a reading on power flow?
Thanks for any insights.

[JoeWay]

Sounds like you have most of it figured out right. One terminal in the box is the connection going to the ammeter, and the other is the connection coming back. Both of them should be negative if you have the battery installed with positive ground as original.

Your last paragraph explains why only one terminal is hot. For temporary purposes, I would disconnect the wires on the engine side of the firewall and jump them together. After you have the ammeter fixed or replaced, and new wires to the dash panel, then re-connect as original.

Joe

[Tom Wesenberg]

This is another reason to carry a couple of clip leads. You can bypass the wires and amp meter by just jumping the 2 wing nuts togerher on the junction box cover. Then you should be on your way and can fix it correctly at home. chances are the nuts are loose on the amp meter, or maybe corroded. ALWAYS make sure ALL electrical connections are clean and tight. I like to put grease or electrical grease on connections to help keep out corrosion. You will have a tight mechanical connection and contrary to many beliefs ordinary grease will NOT insulate the connection when the nut is tight, or even with a slide terminal such as some guys use that rewire the headlights for connections inside the bucket.

I recommend making a couple of 6 foot clip leads, because you don't know where someone might need to jump from one point to another. Six feet should take care of about anything on a Model A.

[Dennis L Oberer]

Email me for a step by step trouble shooting guide....

Dennis L Oberer
Green Bay WI

[SteveB31]

Sponsored Links (Register now to hide all advertisements)

To answer your question, yes, both therminals are negative. They are connected thru the ammeter. Steve