Put in a new Battery, got nothin' - I am not dumb, but maybe I'm not bright?

[BigBlue1]

I Don't know your tractor, but some: You must be in neutral, PTO must be off, Someone must be in driver seat or check that the sensor is connected, Make sure there is not some re-connect setting for when the battery goes completely offline, You may need to make sure the hydraulics are not engaged? The above, of course, are after checking the new battery is live.

The first post in this thread mentions not getting dash lights "or any activity". All those safety switch ideas mean nothing if the tractor doesn't have power to the dash. No safety switch nor any other control position will prevent dash lights from coming on when the key is on. Advice is great, but pertinent advice is kinda a nice thing...

 

[AnotherBueller]

Test from +Batt clamp to tractor chassis Neg. Ignition ON and OFF. Same 12.6 result for each?

You're by passing the switch, thats why the voltage is the same.

 

[AnotherBueller]

If the battery tray is really the ground source I would jumper a wire from the neg side of the battery to ground somewhere close to the battery and see if the dash or lights work.

Since you have lost "all" power the most likely culprit would be a bad ground from the battery = NO POWER or the positive main fuse is blown = NO POWER.

Add a bad positive cable (even if unlikely) and you've got it pretty much covered.

 

[4570Man]

Add a bad positive cable (even if unlikely) and you've got it pretty much covered.

You could spend 5 minutes or less and check the battery terminal voltage while attempting to start the tractor and check it again at the starter terminals while you’re attempting to start the tractor. If there’s a big difference in voltage then you know the cables are making a bad connection or less likely could be bad themselves. In the OPs case the voltage wouldn’t have changed at all but that’s still useful information. I don’t know why probably 99 percent of people won’t check the dang voltage and instead start wild trouble shooting ideas and buying parts they don’t need. I like to take it one step further and jumpstart the machine to make sure it is capable of starting. It’s way less common than crappy connections but the possibility exists that something is locked up and pulling too many amps and dropping the voltage. If the jump starting effort is successful go ahead and measure the voltage with it running to make sure the alternator is working.

 

[4570Man]

You're by passing the switch, thats why the voltage is the same.

The switch is still pulling a relatively small load on the battery though. You’d probably have to measure in 10th of a volt to see any difference but if the switch was actually working and engaging the electrical system I would expect the see a slight drop. If there was a fault in the ground cables you could potentially see a big difference. Or in the OPs case you’d see absolutely no difference at all because the power to the switch was dead and it couldn’t pull any load whatsoever.

 

[SPYDERLK]

Test from +Batt clamp to tractor chassis Neg. Ignition ON and OFF. Same 12.6 result for each?

You're by passing the switch, thats why the voltage is the same.

The voltage should not be exactly the same with the ignition on because "Ignition ON" should result in an electrical drain. The subject 12.63 measured voltage should go down a little. If it dooesnt it shows that there no drain from ignition on.

 

[SPYDERLK]

Setting your voltmeter up to apply a ~ 1A load would go far. Put a 10 Ohm 10W resistor across a double banana plug and apply it at the V meter input. Most all voltmeter leads should carry an amp quite harmlessly.

I use my test light to put a small load on small gauge wires but that wouldn’t prove anything on starter cables.

It would assuming normal discrimination on the ~ 20 V range. Normally the lowest applicable scale for 12V will discriminate to the second decimal ... (0.01V) .

For example, as in the OP case say the battery terminals are 12.63 NO LOAD. With a meter set up to apply a 1A load thru its leads the measured voltage may be 12.59. The loss is from slight battery suppression and loss in the meter leads carrying the current. Now move the Neg probe to a clean chassis ground .. 12.58 -- probably ok.

Affix that probe securely. Now move the + probe from + terminal to the + clamp .. 12.55 -- something wrong there - fix it. Now move the probe onward to the lug at far end of + cable .. 12.56 -- probably ok. Now move the probe to the stud the lug bolts to .. 12.47 - FIX IT. (That loss of 0.09V at 1A would equate to a loss of 9.0V at a 100A starter draw - no response at all, or a chatter click.)

Now, the starter should operate. Remove the meter load setup and get some help while you assess each of the previous connections under the substantial starter drain.

You could spend 5 minutes or less and check the battery terminal voltage while attempting to start the tractor and check it again at the starter terminals while you’re attempting to start the tractor. If there’s a big difference in voltage then you know the cables are making a bad connection or less likely could be bad themselves. In the OPs case the voltage wouldn’t have changed at all but that’s still useful information. I don’t know why probably 99 percent of people won’t check the dang voltage and instead start wild trouble shooting ideas and buying parts they don’t need. I like to take it one step further and jumpstart the machine to make sure it is capable of starting. It’s way less common than crappy connections but the possibility exists that something is locked up and pulling too many amps and dropping the voltage. If the jump starting effort is successful go ahead and measure the voltage with it running to make sure the alternator is working.

Or just do self sufficient meter setup and testing as previously posted.