john deer L100 dies when i let off the brake in reverse. PTO is off.

[tractorfox]

im a john deer technician for south texas implements, tractor city and im working on a customers L100 lawn mower and as I put the unit in reverse with the PTO off the engine dies. unit acts as if the PTO is on. ive checked all the RIO and RIS sensors and the PTO and brake sensors. all are in normal working condition and have continuity. is there and other sensors or relays im not checking or is there a further electrical problem for this unit?

 

[mechanic mark]

John Deere - Parts Catalog

Check RIO switch item 33 part #M125931, transmission mounted.

 

[tractorfox]

I have gone through all of john deer's electrical tests and the transmission mounted RIO switch has continuity and is in normal working condition, is there any other switch that may deal with the reverse or do I need to check the transmission itself?

 

[mechanic mark]

http://ww2.justanswer.com/uploads/K..._deere_l100_l110_l120_wiring_schematic_ii.jpg

Hands on, try unplugging all switches & relays and visually inspecting each & every one starting with the easiest to get to first, as you proceed if you find each to be ok, squeeze some silicone dielectric in each connection before replugging.