JD5210....I found the part RE42470 for $36.99. I could not see where the switch is located. John Deere catalogs are a nightmare. There is only one online operator's manual for the 5105. The rest you have to purchase... and there are operator's manuals, service manuals, transmission manuals, etc. I could spend a fortune trying to buy a service manual to see where the part is located. I found a picture of of the fuel sending unit RE72864 with the link you provided. The cost for that is $114.45. My question is: "Is there any damage I can expect running the tractor with a malfunctioning PTO light on?" PS: If you could help me find out where both items are located, I might fork out the money. John Deere claims to do things right. For all the hoops one has to go through to find the part, see it, and find where it is located, this company is certainly not user friendly when one doesn't have a dealer in your backyard. BTW, thanks for all your help. Ed