John Deere 6620

[Lleyn9876]

I have a John Deere 6620 not a common rail model. Sometimes the battery light starts flashing with the orange warning light but the battery is charging. Any ideas?

 

[kill]

Try cleaning all the earth leads

 

[Phil P]

The dash looks at charge voltage, if I remember right if it drops below 11.5v you get the warning light. It also compares battery voltage and voltage at the controllers, if they are not within ~ 1v of each other it also puts the light on.
Check the battery terminals/earth connections, also check the contacts on the two big fuses at the front as they can get hot and melt the holders!
That’s as good a place as any to start, after that you’ll need the codes out the dash and a good multimeter to check for resistance and voltage drops.

 

[john432]

The carbon brushes on the alternator worn and too short to allways make contact.

 

[Lleyn9876]

Thanks all, will have a closer look tomorrow and hope for an easy fix!

 

[Combine Rescue]

System is designed to measure difference voltage between battery+ supply and d+ terminal. And the trigger is dependent of engine Rpm.
Dashboard also can cause the problem as bad or corroded joints.

 

[pail of ale]

10 series will put light flashing if overcharging aswell as under

 

[Combine Rescue]

10 series it has a bulb as load between battery+ and alternator d+.
Simple

 

[Lleyn9876]

Thanks all. Found one of the maxi fuses at the front had melted.
New problem now!!! Put a new relay in for the glow plug as this was not working. This may not be linked to it. Now my tractor wont start. Good turning over speed, but doesn't sound like it's trying to start as if the stop solenoid was not working. Not very familiar with this fuel system. Can you guys help out again? Thanks

 

[flyonthewall]

That’s what had happen on our 6420 - melted fuse. Not sure what the fuel system is but we had a problem with the plug to the lift pump on ours, I’d crack off an injector union see if you’re getting fuel up there!

 

[marco]

Dodgy thing to do on a common rail?

 

[pail of ale]

Can you hear the fuel pump buzzing with ignition on ?

 

[Lleyn9876]

Yeah fuel pump is buzzing. Was running fine, and now it just wont start no smoke out of the exhaust. Any fuses in the starting circuit or stopping the injection pump getting power?

 

[Lleyn9876]

No power getting to any of the pins on the big plug going in to the top of the fuel pump with the ignition on.

 

[Phil P]

No power getting to any of the pins on the big plug going in to the top of the fuel pump with the ignition on.

You stated in your op that it’s not a common rail engine so I’m guessing it’s a vp44 pump? It’s been a while but if I remember right there’s a 10A fuse next to the heater relay just below the alternator? If you’ve replaced the relay check you haven’t disturb it and you’ve wired the relay correctly. The wires can also rub on the timing cover in this area and blow the fuses. Check the fuse for the ECU in the fuse box behind the seat also.
If it is a vp44 you should be able to here the solenoid making a buzzing/ticking noise when you put the ignition on.

ps, that can be a pig to bleed up if it’s got air locked!

 

[Lleyn9876]

Yes vp44 pump. Checked all fuses, all good. No power at any of the pins still on top of the injection pump.

 

[Phil P]

Yes vp44 pump. Checked all fuses, all good. No power at any of the pins still on top of the injection pump.

I’ll see if I can find a schematic/wiring diagram so can see where it gets power from. It will probably get later tonight though.

 

[Phil P]

Yes vp44 pump. Checked all fuses, all good. No power at any of the pins still on top of the injection pump.

Ok, so functional schematic for injector pump.

but I’d be double checking the fuse next to the heater relay, make sure you’ve got power there.

also check the pump relay at the front as you may have disturbed it repairing the fuse holder.

 

[Lleyn9876]

Thanks very much for that. I'm a little confused now as I thought the glow plug relay was the one at the front as when I put a relay I had into it, it would heat for 30 seconds and then go out. This is when it wasnt starting.
Put the correct relay in from JD and now the tractor starts but wont heat. Is this correct?

 

[Phil P]

Thanks very much for that. I'm a little confused now as I thought the glow plug relay was the one at the front as when I put a relay I had into it, it would heat for 30 seconds and then go out. This is when it wasnt starting.
Put the correct relay in from JD and now the tractor starts but wont heat. Is this correct?

Heater relay is the one below the alternator, just remember the light on the dash is a ECU light not a heater light.