Exmark Lazer Z S Series electrical issue - won't start and blank display module

Mac_man

LawnSite Member
Location
Yukon, Canada
Hi all,
I just encountered my first issue with my Exmark ride on.

Model is LZS740EKC52400 running a Kohler Commander ECV740. Approx 540 hours.

As I was mowing the other day the machine spontaneously shut off. I was able to start it again and it ran for a couple minutes but then shut off again. I thought maybe the seat safety switch got triggered as changed from a slope to flat. Got it running and drove it back to the truck to see if there was an issue with oil or anything. Had sufficient oil but did a quick change just in case. Did the start stop thing again a couple of times and then it stopped for good.
As I turn the ignition key midway I can hear a slight electric whir in the engine for a second but nothing more. The display console is blank regardless of key setting. No hours, no safety switch checks, battery light etc. While the key is turned midway I can pull the PTO engage and it clunks below the machine.
I replaced all the fuses in the console just in case. I swapped out the battery just in case. I disassembled the ignition switch and cleaned any gunk that was in there. Reinstalled it and no change. I get power to the red wire at the ignition switch (approx 12.5 V) so the battery is sending power. When the switch is attached to the wire harness and I turn the key to midway, the other pins on the switch have power but he voltage seemed to fluctuate. Would show anywhere around 3, 4, 5 or 6 volts I don't know if this is supposed to be the case since so many poles on the switch are drawing power. That is all I have to go on for now. I wasn't able to test the pins on the back of the display module. I was hoping it was just a matter of gunk in the ignition switch but it looks like something more. This is the first time I have had to muck about with an electrical issue so not entirely sure what is going on.
Has anyone else experienced something like this and found a solution?
Thanks in advance,
MM
 

JoeRagMan

LawnSite Senior Member
Location
Near TMI
Sure sounds like an electrical connection that has high resistance. Check, clean the battery grounds where they attach to the mower. Also could be a fuse holder/fuse blade. Maybe try attaching a jumper cable from the battery negative terminal to the engine block on bare metal? Unplug each electrical connector and inspect for burnt contacts? Good luck.
 
OP
M

Mac_man

LawnSite Member
Location
Yukon, Canada
Thanks for the response. I'll try the jumper cable between the negative terminal and engine block today. To test the tiny pin connectors do you just use a fine wire to bridge circuits? Would moisture/dirt cause a burnt contact?
Thanks again
 

JoeRagMan

LawnSite Senior Member
Location
Near TMI
I would not recommend sticking anything in the connectors, at this point just unplug them and do a visual inspection. If you find dirt in the contacts, try cleaning them with an approved electrical contact cleaner. I have seen a connector that got hot, one side had turned brown internally on a white connector. It was a poor connection which caused high resistance and no power was flowing.
 
OP
M

Mac_man

LawnSite Member
Location
Yukon, Canada
Figured I would post a follow up. It turned out the B+ wire connecting the ignition switch to the hour display had corroded so badly where the wires were twinned at the ignition side terminal that there was no copper connecting the two anymore. Once I got a new female terminal attached to clean wires the display was getting power, but then the driver's seat safety switch wasn't working. Turns out there is some barely noticeable oxidation at the base of the pin on the hour display receiving power from the seat safety switch. Must be a sign of something more significant under the plastic. I had to order a new display in but hopefully once that is in it will solve the problem. Also ordered a new ignition switch since it could have a problem with the other terminals lurking just around the corner. Will keep you posted. Pics attached (pin is 3rd from top on right side)
 

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