# Craftsman Riding Mower Electrical Problems



## donens (May 7, 2012)

I'm working on Craftsman 20/46, that dies when the electric clutch PTO switch is engaged. Equipment details:
Model:	917.272140
s/N:	022299A002148

Engine 20hp Intek
Model:	407777
Type:	0121-E1
Code:	990206YG
Repair Manual
273521
Last fall, we were cutting the grass, then run out of gas. We refueled, then started the machine, then pulled the PTO switch and it killed the engine. I couldn't see anything apparent wrong, but needed to finish cutting, so I ran a bypass circuit, using a toggle switch directly to the electric clutch. That got me through the cutting season. Now I'm trying to correct the real issue with lawn mower. I have tested, PTO switch, ignition switch, seat and brake/deck safety switch with ohmmeter for continuity. The only thing I was unable to check was the Operator Presence Relay. Don't know how!
I purchased a new PTO switch, ignition switch and safety switches, to avoid any possible problem with them before troubleshooting farther.
The problem is that the unit still starts Ok, but as soon as I pull the PTO switch to engage the electric clutch it kills the engine. Just like if you grounded the coils.
Any help would be appreciated!


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## 30yearTech (Sep 14, 2006)

Look at the plug for the seat switch, many models incorporate a micro switch in the plug, so that you can't just unplug the seat switch and defeat it. Sometimes this causes issues as it's not sensing that it's plugged into the safety switch.

Typically if the problems is the operator presence switch, the engine would also die as soon as you released the brake pedal.


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## paulr44 (Oct 14, 2008)

The wiring schematic can be found in the owner's manual, on page 33, here:
https://c.searspartsdirect.com/mmh/lis_pdf/OWNM/99030709.pdf

From what I can see, the OP relay is dependent on the seat switch as well, so if the seat switch passes muster you have a bad OP relay. Those relays are all the same, and cost about $10 or less.

Terminals (easier to type "pin" henceforth) 85 and 86 are the relay's power control circuit. Pin 87 completes ground to the clutch from the connection through pin 30, else 30 connects to pin 87A, which kills the engine. Mind you, the seat switch as stated by 30yr MUST work (to energize pin 85) for the relay to work, but you've said you've tested that. You could pull the relay and bench test it using a 12V battery.

Hope this helps.


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