GC1720 has no electrical power at all

[Bill Guenthner]

I have recently ran into an issue that has me flummoxed. The tractor has absolutely no power when turning the key(absolutely no lights etc on dash). Parts that have been recently replaced include the starter, neutral safety switch, key switch and the two main fusible links. The battery at the time was good with a full charge.
I was able to jump the starter to start it up so we could move it but I know even doing that the system isnt recharging itself by the alternator. I’ve gotten the repair book for it but for the life of me I’m having a fun time trying to trace the wiring.
I figure it’s one of two things a bad ground(I’ve checked them and they seem good but might have missed something) or the wire going to the key switch that is ultimately the power source for everything.
Has anyone ever encountered this or have any suggestions????

I have encountered exactly that. It turned out to be twigs and grass that got loged between the frame and the shutoff switch connected to the PTO engagement lever right where the wires connect. EVERYTHING was dead, like there wasn’t even a battery connected. Cleaned it out and she started right up.

 

[BusyBacres]

Thank you all for your replies, I drive a truck otr so once I get home I’ll try the tips out and will get back with ya.

 

[lpakiz]

I too would encourage checking out the battery ground and positive cables, but if the OP can start the tractor by jumping the solenoid, those components are OK.
The above advice is spot on--start at fusible link 31. See if power exits at that device.
If so, move downstream to the next junction point(s).
As I've stated MANY times before, use a test light, not a voltmeter. The voltmeter is too sensitive and will show voltage even thru a faulty connection. (Unless you are actively trying to draw power thru it, then the voltmeter is appropriate)
My second caution was also mentioned above, but I word it a bit differently--TEST THE TEST LIGHT FIRST! And I might add--test it often during your search.
I use a vise-grip pliers on some part of the tractor as a ground. I can't count the number of times the alligator ground clip was wiggled just a tad and (unknown to me) I lost the ground).
Follow the schematic just like you would follow a road map--segment by segment. Dont be afraid to backtrack to suuure nothing has changed.
Another strategy Ive used is to "inject" power somewhere down stream, bypassing some or many of the connections. If things function correctly, work "upstream" on your schematic to see where you lose power.

 

[lpakiz]

To further test just the alternator "no-charge" issue, first connect a voltmeter to the battery terminals, then connect a jumper wire to the +battery post and to the alternator output terminal.
Note the battery voltage at rest, then jump the solenoid to start the engine. Note the difference in battery voltage. The "engine running" voltage reading should be several volts more than the "resting" voltage.
A couple of clues point to the big main connection on the starter, and it IS POSSIBLE that a bad connection there can stop small current flows but still allow a large, sudden demand for power (like jumping the starter solenoid) to allow the bad connection to "arc" thru. Usually this is not very consistent, but it could happen once or twice when the OP jumps the starter solenoid. (Remember, a poor connection will generate heat when you demand that it provide power thru it)

I would test for voltage at the exit of those fusible links 29 and 31, with a test light, and I would do it WHILE HOLDING THE KEY IN START POSITION.

 

[Dmacleo]

A couple of clues point to the big main connection on the starter, and it IS POSSIBLE that a bad connection there can stop small current flows but still allow a large, sudden demand for power (like jumping the starter solenoid) to allow the bad connection to "arc" thru. Usually this is not very consistent, but it could happen once or twice when the OP jumps the starter solenoid. (Remember, a poor connection will generate heat when you demand that it provide power thru it)

I would test for voltage at the exit of those fusible links 29 and 31, with a test light, and I would do it WHILE HOLDING THE KEY IN START POSITION.

on gc series + off battery also runs to solenoid then sep wire goes back to feed electrical system.
the no lights on dash with key on as well as key not turning engine over AS WELL as not charging...is odd. that diode leads to the engine stop relay as well as all safety switch relays AND the starter relay....but cannot see anything in schematics about it affecting dash lights or charging.
yeah need to check for batt voltage throughout system before spending money.
and those 2 slow blow fuses also caught my eye. one controls main power and other control charging.

 

[WranglerX]

I have recently ran into an issue that has me flummoxed. The tractor has absolutely no power when turning the key(absolutely no lights etc on dash). Parts that have been recently replaced include the starter, neutral safety switch, key switch and the two main fusible links. The battery at the time was good with a full charge.
I was able to jump the starter to start it up so we could move it but I know even doing that the system isnt recharging itself by the alternator. I’ve gotten the repair book for it but for the life of me I’m having a fun time trying to trace the wiring.
I figure it’s one of two things a bad ground(I’ve checked them and they seem good but might have missed something) or the wire going to the key switch that is ultimately the power source for everything.
Has anyone ever encountered this or have any suggestions????

Can you explain "jump the starter"....

 

[Dmacleo]

Can you explain "jump the starter"....

most likely means to connect starter input direct to battery (bypass solenoid\key switch) causing it to rotate but...its good to check to make sure thats what was actually meant.
is like when people tell you their engine won't turn over while all the time its rotating and just not firing...

 

[WranglerX]

most likely means to connect starter input direct to battery (bypass solenoid\key switch) causing it to rotate but...its good to check to make sure thats what was actually meant.
is like when people tell you their engine won't turn over while all the time its rotating and just not firing...

That is why the question...

I find it odd the its start when "jumped" but not with its own battery.... Leads me to believe problem is either battery related or battery cable related if he is jumping at starter...

 

[lpakiz]

DL,
I can understand the confusion. Usually, "jumped" means to add an additional battery, via "jumper cables".
When someone (I) uses the phrase "jump the solenoid" it means to connect the main starter lug, where the big battery cable connects to the starter, to the smaller terminal on the solenoid, which is the terminal that energizes the starter solenoid. Some random piece of metal (screwdriver, metal rod, wrench, remote start switch, small test wire, etc.) is used to make the connection.
The starter solenoid is usually energized by the key, but if one of a multitude of problems occur in the key circuitry, "jumping the solenoid" bypasses all of those problems and directly energizes the solenoid.

PLEASE NOTE: If the tractor is a gear drive and is in gear, and it starts, its GOING TO MOVE! If you are standing in front of a wheel (and you will be, if you are jumping the solenoid) you will probably be run over. Serious injury (my neighbor) or DEATH will result!! Please use extreme caution when jumping the starter solenoid.

 

[WranglerX]

DL,
I can understand the confusion. Usually, "jumped" means to add an additional battery, via "jumper cables".
When someone (I) uses the phrase "jump the solenoid" it means to connect the main starter lug, where the big battery cable connects to the starter, to the smaller terminal on the solenoid, which is the terminal that energizes the starter solenoid. Some random piece of metal (screwdriver, metal rod, wrench, remote start switch, small test wire, etc.) is used to make the connection.
The starter solenoid is usually energized by the key, but if one of a multitude of problems occur in the key circuitry, "jumping the solenoid" bypasses all of those problems and directly energizes the solenoid.

PLEASE NOTE: If the tractor is a gear drive and is in gear, and it starts, its GOING TO MOVE! If you are standing in front of a wheel (and you will be, if you are jumping the solenoid) you will probably be run over. Serious injury (my neighbor) or DEATH will result!! Please use extreme caution when jumping the starter solenoid.

Yep... Its the terminology that makes a difference by area of country, way person is educated, their own interpretation of situation....

I have people on a auto motive site say their motor wont spin up.... What they are really saying is starter is working but engine will not RUN after starter is turning it over.... And other oddities of descriptions.... This is why I have asked for exact method of procedure....