I, too, was fighting a JLG 2630S issue with the Pothole Switches. Thankfully I found this forum thread and saw the recommendation to enter the Machine Setup area (I needed to enter the Level 2 access code first to be able to make changes) and set the Proximity Switch from "0" to "1" and it completely fixed the issue. THANKS!
The 3121166 manual sure doesn't do a good job on this; the wiring diagram showed the switches in series, but the Section 6 Diagnostic Trouble Code chart for error 256 (page 6-9) clearly infers that is NOT the case, stating the Left switch connects to J1-9 and J1-10, with the right connecting to J1-17 and 18.

Nice to hear...keep an eye on the battery trays, they are made of plastic and the corrosion and weight crack the upper sections a lot..I've dropped a few in my days..barely missing feet

Thanks for the help, I went back threw the menu of the scanner, and noticed the proximity sensor was shown as not installed. Corrected the description and it worked, thanks

These lifts pots can be a hassle...if you replaced them..make sure you changed wiring..they come set normally open I think and need to be normally closed...then verify only at around 6 feet both pothole legs come off both switches all the way..I've had a leg not opening all the way all the time..I ended up replacing both and readjusting both..then verify pox switch is working properly...use analyzer to change country and model..then power off..turn back off...reset to original