Solid State Conversion blew the diode on the solenoid

[2-old-carts]

I am started with a clean slate, no existing wiring, no motor, no solenoid, no accelerator/potentiometer...
Only thing from original cart is the key switch....

Used the CartsUnlimited Diagram from the BGW site.

Components:
Controller: Altrax SR48400
FnR Switch: Heavy duty EZGO
Accelerator: Curtis Type 0-k5 potentiometer/throttle pedal with 5 cables labeled POT High, POT Low, POT Wiper, Switch Output, Switch Common.
- I used POT High in J4, and POT wiper in J5. POT low was NOT used.
- SwOut went to FnR, SwCommon went to Solenoid + spade connector.

Solenoid: Curtis/Albright SW180-93 500Amp
--- documentation indicates :
- BOTH large top posts are positive (and connected by a capacitor)
- the top two spade connectors are positive
- the bottom two spade connectors are negative
- the right hand side of the spade connectors have a diode connecting the + and the -.
Wired in this manner, when I turned the key on everything seemed OK.
When I pushed the accelerator pedal the diode between the + and - spade connectors on the solenoid blew out violently.

I have double checked that I wired according to the diagram but obviously I have done something wrong.

Can anyone lend some expertise to help me figure this out?

Thank you.