Wiring 1/2 ton light switch

[treefarmer104]

I am in the process of wiring my 1/2 ton WC12.
The attached photos show the switch that came with the truck.
I am following the electrical schematic in the Maintenance Manual TM 10-1123/1443.

The manual schematic shows the switch having 5 connectors on the right side - mine only has 4.
The left side has 2 and mine has 2.
The schematic has the ports on the left side (front to back) labelled as: SW, HT. Mine are labelled as SS,BS,A
The schematic has the ports on the right side (front to back) labelled as: SS,S,BS,TT,BHT. Mine are labelled as S, HT, TT, BHT, B
My questions are: Is my switch usable for the wiring?
My switch has all the labelled ports except for the SW?
The schematic shows one lead from the brake switch going to the post labelled SW, which I don't have on my switch, where would I wire that lead to?
Does anyone know what those abbreviations mean?
Would I be better off purchasing a new switch from MWM or VPW than using this switch?
Thanks for any help.

[Dozerman51]

Hellotreefarmer104,
Your problem is that you are using the wrong wiring schematic for your light switch. Your schematic is for the WC trucks from WC-12 T-211 after motor number 42001 which used the 5 connector 919925 in place of your 917280 4 connector light switch. Here are the schematics for your light switch. hope this helps. You may have to rotate them.

[treefarmer104]

Thank you Dozerman!
I will try that, makes sense seeing your schematic.