Starting circuit wiring - Need your thoughts

[dcyrilc]

Been having some issues with the starting circuit on my John Deere 2240 tractor.

Here's a little background: Bought it used about 1-1/2 years ago and it had issues when I bought it. I've found a lot of corrosion in all the wiring connections and the harness wiring is old and brittle. I've ordered new harnesses and will replace them in about a week. The terminations on the starter relay were absolutely nasty.

Deere still sells the origional relay, but recommends and upgrade to an old Ford style starter relay. I bought the new relay today since the dealer had it in stock and wired it into the tractor. No change in performance. Voltage to the relay drops to 8-9 volts when the key is turned to start. At 9 volts the tractor starts and at 8 volts it doesn't. The instructions Deere gives for the upgrade say to wire from the starter battery terminal directly to the input to the starter relay. The factory wiring goes through the neutral start safety switch first so that there is no power to the relay unless the tractor is in neutral. Doing this the tractor starts every time, but it bypasses the neutral start safety switch.:confused2:

I'm curious of everyones thoughts on following the upgrade instructions vs rewiring it per the manual to the new relay when I receive the new harnesses.

The factory wiring does have two features attached to the neutral start safety switch.
A) An alarm sounds if the handbrake is set while the tractor is in gear.
B) No power reaches the starter relay unless the tractor is in neutral.

TIA for your thoughts.

 

[David-Davies]

Hello dcyrilc. Just a thought. If you ran a thick wire, from the starter relay to your clutch safty swith, then to your head lights, and an alarm, that will draw a lot of power, if the clutch wasn't disengaged. With the drop in voltage your tractor wouldn't start, as the voltage would be less than 8 volts. Or you coul;d run the wire through the safty swith, than to a heating element, to drop the voltage. I my self wouldn't worry about it as you still have the nutral safty switch.

David-Davies

 

[SSdoxie]

how many volts at the Battery side of the relay? If you don't have 12+ volts there you are going to have a major voltage drop when start is engaged. If you have cleaned all post connections and/or replaced battery cables and do not have over 12 volts at the battery side of the relay, have your battery load tested. You need to have at least 12.4 volts at the battery with everything turned off.

As for the safety switches, leave them in circuit. As long as the relay is closing, applying voltage to the output side of the relay the rest of you circuit is ok. The neutral switches are on low amerage circuit and have litte to no affect on your voltage drop.

 

[dcyrilc]

Perhaps a better description of the starting circuit will help.

Battery to starter battery post. From there to citcuit breaker, then to key switch. From key switch ignition terminal to neutral start safety switch and then to the battery side of the starter relay. Output of starter relay is direct to start terminal of starter.

Key on and everything else off, 12 volts on battery side of starter relay. (Same if everything is on.) Turn key to start, 8-9 volts on battery side of starter relay. Strong engagement of new relay. Batteries are new as are all battery cables. 12 volts across battery terminals when trying to start and starter not engaging. If jumped directly at the starter, it fires strongly and immeadiately. The starter was rebuilt and reinstalled yesterday. (It smoked after getting filled with hydro fluid - don't ask.:confused2

Relay control circuit: From key switch start terminal to relay+ then from Relay- to ground. Pretty straight forward.

 

[dcyrilc]

Here's a copy of the wiring schematic.

 

[BobRip]

I have seen this in cars. All of the extra wiring and switches cause extra voltage. You can up the wiring size or add an extra relay to drive the starter relay. I had to do this once.

 

[dcyrilc]

I have seen this in cars. All of the extra wiring and switches cause extra voltage. You can up the wiring size or add an extra relay to drive the starter relay. I had to do this once.

I was considering that, but I think I found an easier solution. I'm going to look at moving the neutral start safety switch to the relay control circuit. This will allow me to continue to have the neutral start, but still bring direct power to the relay.

The nice part about having new wiring harnesses coming is that I can butcher the existing one to try different things without having a permanently butchered harness.:laughing: The only issue I see right now is actually finding the wire which supplies the power down to the neutral start safety switch. Never found it today. Currently it's getting its power from either the IGN or ACC terminal reguardless what the schematic shows and all of the current wires in the harnesses are painted green. IMO someone in the history of this tractor was an idiot with a can of paint because everything's green.:confused2:

 

[Hooked_on_HP]

When you put the ford style solenoid in, what activates it. If you run a wire from the battery to the + side of the ford solenoid. Then a wire from the starter side of the ford solenoid to the start side of the solenoid on the starter. Now hook the wire that originally went to the starter solenoid and hook it to the start side (small post) of the ford solenoid. This way the neutral will still work and the start circuit will only have the draw required to activate the ford solenoid.
Bill

 

[dcyrilc]

When you put the ford style solenoid in, what activates it. If you run a wire from the battery to the + side of the ford solenoid. Then a wire from the starter side of the ford solenoid to the start side of the solenoid on the starter. Now hook the wire that originally went to the starter solenoid and hook it to the start side (small post) of the ford solenoid. This way the neutral will still work and the start circuit will only have the draw required to activate the ford solenoid.
Bill

Thanks for your input Bill. That's what the instructions say to do. The issue is that the control for the relay comes straight from the key switch and doesn't include the start safety switch. The start safety switch is in the circuit from the battery to the starter 'S' post (per the schematic and real world). That's the change I'm going to look at doing today is to move the start safety switch to the control circuit. I think this was simply a poor design by Deere since most tractors today have it in the control circuit.

The biggest challenge is going to be to maintain the alarm circuit. The way it's factory wired, the alarm sounds if the barking brake is on when the tractor is put into gear or it will also sound if the tractor is attempted to be started while in gear reguardless of the setting on the parking brake. It also, of course, will not physically start in gear.

 

[SSdoxie]

Add the extra realy as described. Leave all current wires to battery + side of starter(#30 psot) but add another cable from there to the new relay. Disconnect #2 wire from the starter post (#50 on schematic), use this as the activation for new relay and run another cable from relay to stater #50 post. This should leave all switches and warning alarms working as original.