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Chief knucklehead here :)banghead:) tried to save some $$ by bypassing the parking brake switch; crossed the wrong wires :oops: , heard a click, smelled electrical smoke smell - won't crank now. Does anyone have any advice (besides taking it to the dealer) on what to check?

I've already checked two fuses on the left side (no love). It would be of great help if someone had an electrical diagram showing the possible failure parts (ignition module, engine controller, etc.). I have a fair electronics / electrical skill set (except bypassing a brake switch).
 

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I have a fair electronics / electrical skill set (except bypassing a brake switch).
:lolol:

Sure wish I had a schematic to send you. It is the least I could do in return for the laugh you gave me!
 

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Chief knucklehead here :)banghead:) tried to save some $$ by bypassing the parking brake switch; crossed the wrong wires :oops: , heard a click, smelled electrical smoke smell - won't crank now.
You could try some of this, but I think it may be the wrong polarity. Lucas Replacement Wire Harness Smoke

Sorry, sometimes I can't help myself. Hope you get it sorted out.
 
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During the first day of school for aircraft mechanics electrical class, we were told the secret ingredient to all wiring is not ohms, voltage or amperage..... its smoke. And as long as you dont let the smoke out of the wire, then everything is wired correctly.

Sorry, had to throw out that golden nugget of info. :hide:
 

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Sorry, I wish I had the diagram for you. I could swear the owner's manual had it? Maybe not... but worth the check.

:wgtt:
 

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When you heard the "click" and smelled the smoke, what area or the tractor where you think it came from? If it was up front on the left side, the Park/Brake switch probable blew. A click sound usually indicates a fuse has blown, and the smoke would come where the "shorting of the wires" occur.

The first thing I would do is remove the Park/Brake switch to see if there is any burnet marks on it where wires have shorted out. The next thing is go back to the engine and locate the Voltage Regulator or it may be called the Rectifier. You can test that with a voltage tester to determine if there is 12 volts there to any of the wires. Also, you need to take ...if you have one. a remote starter button to connect to the starter Bendix and ground and press the button to see if the starter will turn over.

Next thing is to remove the instrument panel and check the two replays under it.. The seat and start relays. Also, the Park/Brake switch is tied into the Seat Switch. However, I don't see the seat switch having blown, as you would have some burnet wire damage there at the seat switch. But, it worth checking out. Somewhere on the tractor one electrical unit has been damaged.

Now, the big question. How was altering the Park/Brake switch going to save you some money?

John Deere loves to make their electrical system so they benefit when any of (we) owners try to alter their system. Of course, many lawyers have written into these manufacturers laws that they too benefit from mistakes. All for the all-mighty dollar.
 

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As said, why were you trying to bypass the parking brake switch? Was it bad? You have to have the park brake engaged, butt on seat and PTO off for the starter to engage. These are good places to start. Obviously if the park brake switch is not hooked up, bad or melted the unit won't start.
 

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Charlie, here is the way to test the Park/Brake Switch.
1. Turn key to off position.
2. Release park brake lever.
3. Raise and latch the seat platform.
4. Disconnect brake switch from the wire connector.
5. Use a Digital Multimeter to test continuity.
6. The two longer metal tabs in the switch...on left side) There should be continuity across these two tabs.
7. The other two tabs ...shorter ones (right side of switch. There should be NO continuity across these.
8. Fully depress the brake plunger and hold it depressed.
9. There should be NO continuity on the two longer (left side) tab.
10. There should be continuity on the two shorter (right side) tab.

NOTE: If continuity is not correct, replace the switch.
 

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Discussion Starter #11
The smell and sound came from the rear of the engine area. I have bad hearing and I may be wrong. The switch was out of the tractor and I had jumpers on it to fool the system to think the switch was closed (lesson already learned). If I can bypass the brake switch, I won't have to replace it.
 

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When you heard the "click" and smelled the smoke, what area or the tractor where you think it came from? If it was up front on the left side, the Park/Brake switch probable blew. A click sound usually indicates a fuse has blown, and the smoke would come where the "shorting of the wires" occur.

The first thing I would do is remove the Park/Brake switch to see if there is any burnet marks on it where wires have shorted out. The next thing is go back to the engine and locate the Voltage Regulator or it may be called the Rectifier. You can test that with a voltage tester to determine if there is 12 volts there to any of the wires. Also, you need to take ...if you have one. a remote starter button to connect to the starter Bendix and ground and press the button to see if the starter will turn over.

Next thing is to remove the instrument panel and check the two replays under it.. The seat and start relays. Also, the Park/Brake switch is tied into the Seat Switch. However, I don't see the seat switch having blown, as you would have some burnet wire damage there at the seat switch. But, it worth checking out. Somewhere on the tractor one electrical unit has been damaged.

Now, the big question. How was altering the Park/Brake switch going to save you some money?

John Deere loves to make their electrical system so they benefit when any of (we) owners try to alter their system. Of course, many lawyers have written into these manufacturers laws that they too benefit from mistakes. All for the all-mighty dollar.
The smell and sound came from the rear of the engine area. I have bad hearing and I may be wrong. The switch was out of the tractor and I had jumpers on it to fool the system to think the switch was closed (lesson already learned). If I can bypass the brake switch, I won't have to replace it.
 

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Discussion Starter #13
Charlie, here is the way to test the Park/Brake Switch.
1. Turn key to off position.
2. Release park brake lever.
3. Raise and latch the seat platform.
4. Disconnect brake switch from the wire connector.
5. Use a Digital Multimeter to test continuity.
6. The two longer metal tabs in the switch...on left side) There should be continuity across these two tabs.
7. The other two tabs ...shorter ones (right side of switch. There should be NO continuity across these.
8. Fully depress the brake plunger and hold it depressed.
9. There should be NO continuity on the two longer (left side) tab.
10. There should be continuity on the two shorter (right side) tab.

NOTE: If continuity is not correct, replace the switch.
Thanks for this great information! I wish I had it before. I had the switch out and the plug in my hand and crossed the wrong wires; thus the magic smoke smell and the 'pop' sound. Any idea on what I burnt up?
 

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Give thanks to...ExperimentalMechanic for the wiring diagrams here.

Charlie, can you unplug the PTO switch at the rear? If so, do that to see if you can start the tractor, or get it to turn over. If not... Do you have a great "nose" for smelling? If that is also good. You must try to sniff all the relays....Start/Park/PTO/Seat relays for any burnet odor. Most of the time any burnet unit will leave a smell. So, remove the instrument panel and the two replay there... they have wiring plugs to them you can disconnect.

The only two items at the engine rear is the two fuses and the voltage regulator and the engine stator, and of course the PTO unit. 90% of the time you hear a "Pop" it is a fuse.
 

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I much prefer the "pop" to sizzle. :laugh:
 
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Thanks for this great information! I wish I had it before. I had the switch out and the plug in my hand and crossed the wrong wires; thus the magic smoke smell and the 'pop' sound. Any idea on what I burnt up?
When you shorted out one of the two wires on the Park/Brake wiring connector, all those wires tie end to the K1 (Seat Relay) and K2 (Start relay), and the other side of the connector tie into the PTO switch. So, I first would look at the Seat relay, and on to the Start relay. I think one of those two took the blunt of the shorting of the wires in the Brake/ Park wire connector.
 

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You said you checked the fuse. Which one F1? Did you check to see if there is 12v+ at the fuse? Looks like 12V+ goes from the battery + terminal to a terminal on the starter and then onto the fuse. Thats a lot of unprotected wiring. Wouldn't surprise if there is a fusible link in there somewhere.

Check for 12V+ at the fuse and the terminal on the starter. You could try jumpering the starter as well just to rule out something in the starter getting fried.
 

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You said you checked the fuse. Which one F1? Did you check to see if there is 12v+ at the fuse? Looks like 12V+ goes from the battery + terminal to a terminal on the starter and then onto the fuse. Thats a lot of unprotected wiring. Wouldn't surprise if there is a fusible link in there somewhere.

Check for 12V+ at the fuse and the terminal on the starter. You could try jumpering the starter as well just to rule out something in the starter getting fried.
You are correct to say...check the wire that has the fusible link.. The main F1 wiring does contain a fusible link.

However, I have a feeling the owner sent the 915B to the dealer for them to iron out, and a hefty $300.00 invoice to be paid.
 
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