ECB,
Good idea with the switch. Fortunately I can just go around the block and come from the uphill direction anyway. That way my drive is on my left and I can see while backing in. I could always put a switch on my backup lights anyway;) .

I have the big round plug and rather than buying the big plug, I just found an electrical connector that fit the backup pin. I was running from that and my cab switch to the same line going to the solonoid. Again, I found that I was always using the switch in my cab. I used bullet connectors so if I want to use the backup connection again, I can just plug it right in effortlessly....