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Toro Zmaster 74292 Safety Switch Issue

Discussion in 'Mechanic and Repair' started by Doublewide6, Apr 8, 2019.

  1. Doublewide6

    Doublewide6 LawnSite Member
    Messages: 227

    Hello,
    I have a commercial zero turn that will not shut down if I'm off the seat and the brake is off. Will not shut off if the brake is on and I try to drive forward. Will not shut off if I get off the seat and the blades are ingaged. I checked all the switches (parking brake, both drive levers, and seat switch, and they seem to be working just fine, so I could use a hand in diagnosing what is up with this unit. Also I could not find any safety switch that is activated by the electric PTO, so I was wondering how the unit determines that blades are engaged. Thanks for any help.
     
  2. Walker56

    Walker56 LawnSite Fanatic
    Messages: 7,780

    hort101 likes this.
  3. OP
    OP
    Doublewide6

    Doublewide6 LawnSite Member
    Messages: 227

    Thanks for the help. I found 2 relays and I blew them out with compressed air and switched them. Switching them made no difference. Where would I find the delay module?
     
  4. OP
    OP
    Doublewide6

    Doublewide6 LawnSite Member
    Messages: 227

    Found it on google. I'm going to run the test procedure on this module and report back. I'm thinking the relays are good because switching them made no difference? Thoughts?
     
  5. Walker56

    Walker56 LawnSite Fanatic
    Messages: 7,780

    Last edited: Apr 9, 2019
  6. Walker56

    Walker56 LawnSite Fanatic
    Messages: 7,780

    I just looked and based on the serial number, there are two different schematics. One uses a separate delay module and the other utilizes a module that has the hour meter built in. Go back to the Toro link I posted and ensure that you look at the correct schematic for your specific serial number.
     
    hort101 likes this.
  7. OP
    OP
    Doublewide6

    Doublewide6 LawnSite Member
    Messages: 227

    Okay, I took a look at the delay module (found it below the seat/above the storage console). Part number 100-6186 and I ran the test on the module and it seems like it is working because the blue relay clicks and the voltage drops, but it is not delayed much at all. Seems to me it is less than 1 second and the test says it should show hold voltage for 1 to 3 seconds. I'm not sure if the module is faulty or on the way out? I don't think this mower has a mercury switch. I unplugged the delay module and the mower works the same way it did when the module was plugged in. What do you recommend? Thanks Bob
     
  8. Walker56

    Walker56 LawnSite Fanatic
    Messages: 7,780

    I would follow the schematic starting at the kill relay. The yellow wire (coil feed) should lose its potential when a safety is tripped or the delay is too long. With the key off as an example, as shown in the schematic, the voltage is lost on the yellow wire causing the contact to drop out carrying a ground to the coils. So, the yellow wire should always be energized in the run position as long as all safeties are satisfied and the operator is on the seat. You need to trace back and find out what is not operating properly to cause the yellow wire not to lose its potential.
     
  9. OP
    OP
    Doublewide6

    Doublewide6 LawnSite Member
    Messages: 227

    Okay, thanks again for the great help. Here is what I found. I ran my meter from the yellow kill relay and to the battery neg. I found a resistance increase when I tested all safety switches except the seat safety switch. I bypassed the seat switch and the resistance stayed the same. I continuity tested the the 2 seat switch wires and they are fine they both run to the delay module. I'm thinking the current is not getting through the delay module? I left the key in the off position for all these tests.
     
  10. robmints

    robmints LawnSite Member
    Messages: 14

    Sounds like a bad ground connection. Or bad control. You can bypass the control to test the switches. One sw is nc, another no.
     

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