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lampoulos

Electrical Desperation

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lampoulos
Alright guys. I really need your help here. My 6212.5 (#1691240)has some sort of an electrical gremlin. As it sits right now it will only crank over by crossing over the start relay, but not at the key switch. Testing shows that I'm only getting power into the key switch and into the charging system when the key is in the crank position. I tested with a keyswitch I know is good and had the same results. All the safety switches are bypassed while I'm testing and all are sitting at about .03 ohms each. All the diodes past testing (there's four in the system) and are going to correct direction. I did accidently cross over a wire with the ammeter and the green wire going to the pto safety switch. The only thing I don't know how to test is this DSI interlock switch. And being this feels like a ground issue I'm wondering if that's the culprate. Does anyone know how to test it? HELP, HELP, HELP!!!

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AC_B-1Novice
I don't understand all you have said but I just went through a very similar situation for 2 hours today on my 7012. What I found was that the amp meter wires were not making a good connection even though they looked bright. I took them off the amp meter, filed them and connected them directly and the tractor fired right off. I had previously jumped these with an alligator clip and got nothing. I could have sworn they were making connection the first time. Don't know if this helps but I would try it to find out. larry

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lampoulos
Thanks for the advice AC B-1Novice. This was bothering me so bad last night that I ended up redrawing the wiring schematic looking at the parrallel circuits in a more simple manner and figured out that I could isolate the entire safety circuit from the rest of the harness by jumping a remote switch into the "S" terminal of the start switch. Once I did this I realized that the entire circuit was actually working properly, including the interlock module, even the warning lights on the dash! Now that I know this works and I'm getting power to the proper terminal to the start switch I can honestly say that I've convinced myself that the start switch is bad. I just wish I had a diagram of the electrical flow inside the switch itself so I could prove it further. I had the same results from another keyswitch I pulled off one of my other tractors, but it was the same part numbered switch. I'm starting to believe that I have the wrong switch entirely. Does anyone know what the red wire coming off the fuel shut-off circuit is for coming off the back of the start switch. According the the schematic from Simplicity it goes no where. Maybe it's for accessories?

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AC_B-1Novice
Craig...you are far more advanced in this than me but sometimes we overlook the simple things that a novice would think of. Have you tried jumping the wires from the back of the switch one by one or as needed to test the switch? Maybe that is not so simple to do, I don't know but if you can do it, it would let you know if it is the switch that is bad. I would think someone would have chimed in by now but they have to have a pretty good knowledge of your wiring. Good luck on it. I will follow your posts as I am curious about it. larry

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JimDk
I use my ohm meter to bench test ignition switches. I hold the switch in my bench vise. Clamp one probe of the test meter to the input terminal. You can operate the key and test each function of the switch without causing any blown fuses or short circuits. The grounding function for magneto ignitions can also be proved. Good luck, Jim

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lampoulos
You're right Novice I've found often times when I'm working on something the problem usually can be found by simply taking a break from troubleshooting it. Actually what I did to test the start switch was much like you and Jim have suggested except I tested for voltages instead of ohms. This go-round I started by first testing what's going in and out the switch at all three functions (I had voltage in, but none out). Then I switched to reading continuity to make sure there was nothing wrong at the terminals at the plug for the start switch and the main plug separating the upper and lower harness. This was enough for me to order a new switch. I'm actually getting it today (it takes a while to get parts up here in Grand Forks, North Dakota) and am anxiously waiting to find out the results. I'd love to hear this mower run today!

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lampoulos
Well guys I went to pick up the new ignition switch, and low and behold, the new one was completely different. The previous owner must have had issues with the switch before and replaced it with the wrong one. I made the mistake of assuming it was correct. Well I already got it back together and took it for my first drive since I got it, and she's a beuty!!! Thanks for listening.

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w2507c
Hi, have a 4212H and checked all Interlock switches corret, replaced start switch (needed it anyways) and then the solenoid. Still nothing. Does anyone have a detailed electrical diagram breaking down the DSI Interlock switch and interlock switches themselves with the ignittion circuit so I can figure out where is going wrong? I really don't want to keep easter egging espcicially when the DSI Interlock is a $60.00 part. Any info apprciated through here or my email: w2507c@email.mot.com Thank youy ahead, Tom

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lampoulos
If your tractor has a harness like mine (I'm sure it does), you basically have two sides to the circuit. One is safety, which contains all your interlock switches; and the other is ignition. If you already tested all your interlock switches bypass the entire safety circuit from the "S" terminal of your ignition switch to the ground coming out of the DSI. That's the only way I've found to be sure there's a problem.

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