Quote:
Originally Posted by Tom Wesenberg
Wire it just as you posted in #7 then turn the lights on. If the ammeter shows charge, then reverse the wires on the back of the ammeter. Connect the instrument light wire to the ammeter post with the yellow/black wire, so it shows discharge if left on. Install the black coil wire to the terminal box post with the yellow/black wire so it also shows discharge if the key is left on and the points are closed.
Originally the coil black wire went to the terminal box post with the yellow wire that runs down to the starter switch. This way the coil draw doesn't show on the ammeter, which I didn't like, so I changed my 28 to the other side. Changing to the yellow/black terminal box post also makes it easy to see if the points are conducting when the key is on and the points are closed.
As a final check for coil polarity, check what Chicagoland MG Club has written about it.
http://www.chicagolandmgclub.com/tec...neral/574.html |
As verification for the above, I just replaced my junction box and replaced dash wiring. It was done as above and I had to reverse my wires at the ammeter from the per spec diagram. This was done as Tom above and others have pointed out. There have been several posts on other threads about ammeters being reversed.
This was a good thread for clarification.
1) There are two ways to wire a standard Model A, factory:
a) Pre-29 b) Post-29
2) With engine off, lights on, the ammeter reads a discharge. If not, simply reverse the wires on the ammeter. Done.