Generator Battery not charging?

[John Mann]

I have had this gremlin for some time now. I have posted before and
received much information and help on the Solenoids under the Air step
all three ok wires ok, Solenoid in generator compartment ok but I
can't find the diode that is suppose to be somewhere up front left
that allows current one way I think. Where is it on a 1985 pt40? What
does it look like? There is a panel of sorts in the area that has the
battery, there are a bunch of wires coming off of terminals and there
is a Bosch 1x1x1 black square that has a couple of wires connected
just below this board about a inch is this the Diode? When I use the
aux bat switch it does click and will start the main engine when
depressed and will increase the starting of the generator when that
bat is low. I need to find the diode and check it out and then further
check the solenoids. The generator bat will just not charge off of the
battery chargers.
I appreciate any help as always thanks.

John Mann
1985 pt40
Granbury Tx.