# Dead man switch not working.



## dcinma (Dec 13, 2017)

Noticed today if I release the interlock lever that kills the motor when the attachment drive is engaged is not working. Motor stays running with the auger going. Never did that before.
The only thing I have done lately is replace the points, condensor, and coil. I think I have all the wiring okay. I removed the interlock switch and tested it on my DMM and it's fine.
I can still use the machine but don't like not having that safety devise not working.

There is a device on the right side of the case hooked up to all this called a Module T, can't find much info about it but I think it has something to do with a delayed shut-down for the kill switch. It's an $80 part so not something I'm going to replace unless absolutely necessary.

I'm trying to think where I might have gone wrong with the wiring when I had it apart. The ignition switch still works.


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## RIT333 (Feb 6, 2014)

What model machine do you have ? I didn't realize that Ariens had a kill switch on the hand-grip area. Neither of mu Ariens have that.


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## Shaw351 (Nov 15, 2016)

6heres the diagram. Hope it helps. I believe I have several of those safety setups in a spare parts box here somewhere, if you want it I'll send it to you. No charge for parts, we can split the shipping.... believe it will fit into one of those small flat rate postage packages for like 10 bucks.


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## toromike (Aug 20, 2018)

dcinma said:


> . . . I'm trying to think where I might have gone wrong with the wiring when I had it apart. The ignition switch still works.


Check that the white wire from the interlock cable (ref. no. 177) is connected to the proper location. Check that the connector to the Module T is making good contact and is not corroded. Check that the Module T case has a good ground (ref. no. 62). If the switch works, the interlock cable white wire is connected properly, the Module T ground is good, there are no broken wires and the connector is good, then the Module T is bad.

For the Module T wiring see this diagram
https://www.partstree.com/models/92...r-8hp-tecumseh-sn-022001-above/drive-train-0/


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## dcinma (Dec 13, 2017)

It's a 924038 forgot to put that first.
If it is the module t, what does it actually do? Is there a work around that will let the interlock still function.


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## toromike (Aug 20, 2018)

When the lever that has the interlock is in the engaged position (augers turning), is the interlock switch open or closed?


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## dcinma (Dec 13, 2017)

That I'll get back to you on. I Ave all the wiring apart now checking for continuity and cleaning connections.


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## toromike (Aug 20, 2018)

You said you removed the interlock switch and tested it and it was ok. Test the switch while it is installed in the machine, disconnect the connector from the Module T and connect your meter to the two red wires on the connector that are attached to the switch and see if you can get the switch to change states while you operate the controls. There could be something wrong with the linkages that don't allow the switch to operate or there may be wear somewhere that prevents switch operation.


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## dcinma (Dec 13, 2017)

When the switch is pushed in it is "on", unpushed is "off".
I tested all connections for continuity, good.
Cleaned and re-did all connections.
Checked all the wiring according to the diagrams, good.
I tried checking the "module" with the diode function on my multi-meter but did not get any conclusive results. Some people say this module has diodes, or a combination of diodes and capacitors but no real information is available.

So I think it is the MODULE T. Must be a coincidence that the module died at the same time I replaced the points, coil, and condensor. (in a different post).


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## toromike (Aug 20, 2018)

Make sure the mechanical mechanism in the machine is operating the switch properly. If the switch is operating properly, and the circuit checks out electrically, that points to the Module T as being bad. If you can take some resistance measurements of the Module T that would be of interest to me. Disconnect the connector to the module, set your DMM to resistance, clip one meter test lead to the ground connection, using the other meter test lead measure and record the resistance at the two yellow leads and the red lead at the connector.


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## GoBlowSnow (Sep 4, 2015)

So you have a ST724.


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## dcinma (Dec 13, 2017)

GoBlowSnow said:


> So you have a ST724.


Yes basically, before they started putting the ST724 logo on them.


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## dcinma (Dec 13, 2017)

toromike said:


> Make sure the mechanical mechanism in the machine is operating the switch properly. If the switch is operating properly, and the circuit checks out electrically, that points to the Module T as being bad. If you can take some resistance measurements of the Module T that would be of interest to me. Disconnect the connector to the module, set your DMM to resistance, clip one meter test lead to the ground connection, using the other meter test lead measure and record the resistance at the two yellow leads and the red lead at the connector.


This look at the socket from a rear would position with the harness plug removed.
Top yellow wire = 1.086 k ohms.
Middle red wire = 2.06 k ohms.
Bottom yellow wire = 0 ohms, direct path to chassis ground.
These are the wires that go into the module.

Keep in mind, the colors of the harness connector that plugs into this has different colors two reds to match up to the two yellows and a white to match up to the red. I'm positive these are original.

Yes I did verify the operation of the switch. Lever handle engaged = switch is on, depressed for a closed circuit. Lever handle not engaged = switch is off, open circuit.


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## toromike (Aug 20, 2018)

Thanks for the measurements. The Module T is different from the measurements I got from a Toro interlock module (2k, 20k, 0). It does give me more information about how they are building these things. I just posted a reply in the "Info on Toro Safety..." thread about how to possibly eliminate the Module T and still have the interlock function, it involves changing the switch to a normally closed type.


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## dcinma (Dec 13, 2017)

a


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