John Deere 310E Backhoe with electrical gremlins?

JL Sargent · Jul 15, 2018

I bought a backhoe and it has a few quirks I'd like to get to the bottom of and hopefully somebody has experience with these.

1) Yesterday while operating the machine I noticed that the hour meter stopped working and the battery lamp came on. This seemed strange as tractor cranked and ran just fine after I noticed this, but overnight the battery died which previous owner warned me about it doing when sitting.

2) Does not seem to shift out of 4 wheel drive. I wonder if this could be related to my battery problem? Could the solenoid be shorted or something? The 4WD switch indicates that it is going in and out of four wheel drive, but front tires always pulling.

Any help would be appreciated.

Bls repair · Jul 15, 2018

Check battery and charging system. All switches off,interior lights off ,four ways off. If no improvement try putting on a battery disconnect switch.

JL Sargent · Jul 15, 2018

Yes, I have considered a switch to turn off power to the battery to stop the parasitic drain. The problem with the hour meter though is a different one. Wish I could locate a wiring diagram for this machine.

Delmer · Jul 15, 2018

2) yes it could be battery related, fix 1 first

1) the tachometer runs off the W terminal of the alternator (AC that corresponds to engine RPM), no alternator output means no tachometer.

It continued to run and start because the battery can store some power. It may have drained the battery because of failing diodes (rectifier) in the alternator, or it could have died because you continued to use it when it wasn't charging. A disconnect shouldn't be needed, and won't fix your problem.

Start at the alternator, with a charger on the battery and the engine off overnight, is the alternator warm? check it with a non contact thermometer, that would indicate leaky diodes, cheap and easy to replace. If it doesn't warm up the alternator, then diagnose the alternator not charging running, it needs "excitement" from the ignition key to charge.

JL Sargent · Jul 15, 2018

Good stuff! I'll check in to those suggestions tomorrow and report back. Thanks guys.

Delmer said:
the tachometer runs off the W terminal of the alternator

So I'm guessing the battery light is looking for a specific charging voltage that it's not seeing?

Delmer · Jul 15, 2018

Like I said, the tach and possibly hour meter run off the alternating current from the alternator.

The battery light typically runs off the excite current from the ignition key. When the key is on, engine is off, the alternator is consuming power to excite it, that lights the warning light. When the engine starts and gets up to normal speed, the alternator stops consuming power from the ignition switch, and that light goes out because there is no current flowing.

You need a multimeter to check the charging voltage.

JL Sargent · Jul 16, 2018

Charged battery and did not notice any warming of diodes. I then disconnected wire at the W terminal and immediately reconnected. Started tractor and Tach goes back to working and the battery idiot light goes out. I measure voltage at battery while running and its 14v. I then measure for AC at alternator B+ terminal and I do have 62mv there?

So I'm thinking I had a bad connection at the W terminal, but I also have leaky diodes in my rectifier. Do you agree? Thank you.

Delmer · Jul 16, 2018

No, I don't agree. You can't diagnose an intermittent problem when you want to, you'll have to wait till it happens again. It's not uncommon for electronics to fail when they get hot, then work again when they cool off.

In the mean time, disconnect your ground cable when it's off.

You won't get AC at the B+ terminal, only the W terminal or whatever the tach drive is labeled.

JL Sargent · Jul 16, 2018

That's right on intermittent problems. Air Condition coils are notorious for doing that.

I was at the B+ terminal (which is the rectified output) looking for leaking AC current. Apparently a small amount is expected but I'm nut sure 62mv is ok or not.

Delmer · Jul 16, 2018

That's news to me, where did you read about the AC leaking into the B+ terminal, that would be an interesting test of the diodes.

62mv doesn't worry me at all, fwiw. The W terminal should be 14-28V, can't remember how they work.

JL Sargent · Jul 16, 2018

I helped out at a welding shop when I was a young fella and we would look for AC at the DC lead connections. This would indicate that one of the high amperage diodes had shorted. This video also explains it at the 12 minute mark.

br1474 · Jul 17, 2018

Ok so the 310E will default to 4wd when power is lost to the MFWD coil. This is backwards from a lot of equipment but is the truth. It is also common for the accessory solenoid/relay to go bad in the dash of the Deere backhoes. In the 310E it is on the back of the AR73144. Unless it is melted though you will have to catch the issue in the act as mentioned before.

JL Sargent · Jul 18, 2018

br1474 said:
it is on the back of the AR73144.

Is this the same thing at the starter relay? Round relay under the fuses?

I have been hunting for this problem. We pulled all the fuses out and replaced with no luck and even pulled the wire off the B+ terminal. Took a break from it and just went back. With key in off position, the DC amp clamp slows no current through battery + wire right now. I'm gonna run the tractor for a bit and try again.

JL Sargent · Jul 18, 2018

Update: My problem seems to be 4WD circuit related. Oddly enough when I put the tractor switch to 4wd the parking brake turns off like it should. When I go to 2wd the parking brake stays on. Where to go next on this?

Maybe test the 4wd solenoid and where is it located? I'm guessing it is the lowest one on the side of the trans? How to test this? Thanks!

br1474 · Jul 18, 2018

No the large wire on the switch side of that relay is only energized durning cranking. It is taking the electrical load for the key switch. So looking at the parts diagram that can be found on Deere's website. The bottom solenoid coil is for MFWD. I would unhook it and see if the problem is the same. Using an ohm meter the coil should test about 10-15 ohms. or just switch with one of the other coils they are all the same. Food for thought the coils on the left side of transmission are from the top down, Diff lock, Park Brake, MFWD

JL Sargent · Jul 18, 2018

Thank you for that. I was thinking this might all be just one problem but now tractor will not move in Forward or Reverse for some new reason I guess. Parking brake lights do turn off, but no movement. I elaborated more on the dipstick thread.

br1474 · Jul 18, 2018

not trying to be smarty pants but is the shift lever on the floor in gear?? or is this a power shift model?

JL Sargent · Jul 18, 2018

br1474 said:
not trying to be smarty pants

I deserve it!

My 14 year old son who has been helping me with it apparently took it out of gear. Now on to testing that coil! It will be tomorrow though. I'm gonna make a probe set to get down on those pins. THANK YOU SO MUCH for the help on this. I want to get everything right on it before I spring for tires $$$$

br1474 · Jul 18, 2018

I have had at least one service call back in the day for such an issue as this while working at Deere. Those are technicians fishing stories. LOL

JL Sargent · Jul 18, 2018

Uh huh, and you just caught another one for the memory books.

If I worked for Deere on these machines, I would make me a test lead set with that solenoid connector on the end of the leads. Wouldn't that be sweet to just plug the solenoids in to your Fluke multimeter for a quick resistance check.

John Deere 310E Backhoe with electrical gremlins?

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