Yet another 4010/4020 12v-24v question

Hi all,

I acquired a solid JD 4010 last August to replace my beloved 4020 that was incinerated in a fire in June. The 4010 has a 12v alternator and 2 12v batteries, but benefits from a 24v starter which spins it
like no one's business. Instant starts. The tractor has a Delco Remy 119845 1500A starter relay, that combines the 2 12v batteries to provide 24v to the starter, but reverts to 12v once running.

When I reassembled the dash after replacing the steering valve my electrics were non-functional. The original wiring was in pitiful shape, so I installed a new harness. All good, except for the one wire
that controls the battery combiner relay. I stupidly failed to trace all the connections prior to disassembly, so am not sure where the signal that controls the combiner relay originated.

According to a diagram supplied by Texas Industrial Electric Co., the starter signal should go to Terminal 7 on the relay from BAT-A on the starter switch. When I do that, however, the relay doesn't
energize and the 12v going through the starter isn't enough to start things. HOWEVER, when I connect to the ST terminal on the starter (key) switch, it spins and starts right up. However, for some
reason the relay doesn't de-energize, so the starter continues to spin after I return the key to the "run" position.

According to the diagram, and helpful Sharpie numbers the P.O. put on the solenoid, everything looks connected appropriately to the terminals indicated in the TX Industrial wiring diagram. When I
connect Terminal 7 to anything other than the ST terminal on the starter switch, I only get 12v to the starter. When I connect it to the ST terminal the starter spins with 24v, but doesn't stop spinning.

In the photos: The yellow wire is the signal wire from the starter switch, going to the "live" side of the relay. The red lead on the smaller terminal waist-high *should* be the trigger circuit to close the
relay, and *should* go to BAT-A according to the Texas Industrial wiring diagram. However, I only get the relay closing (but not opening) when I connect the red lead to ST on the starter switch. All the
leads in the 2nd photo (right side looking at the relay) lead to ground.

Any guidance from the crowd??

Thanks for the Wisdom of the Crowd.

- David in CA.

I'm surprised you haven't got a lot of replies to this, LOL!

I think I know what you've done, but first I need to know for sure where the other end of the red wire goes.

Can you post the diagram from Texas Industrial Electric Co.? That may help us diagnose the problem. Or maybe direct us to a link that will give the diagram.

Hi Ron-

The image should be attached here. Sorry, I couldn't figure out how to include it in my original post. I did talk to Steve at Texas Industrial Electric today- super helpful guy. He confirmed that the relay signal should come from the ST pole on my starter switch to terminal #7 on the relay. When I did that, the relay kicked in as it should to combine my 2 x 12v batteries to spin the 24v starter... but then didn't disconnect so my starter continued to spin after the engine started. I could only disconnect it by disconnecting the batteries.

I need to confirm now whether the ST terminal remains 'live' for some reason... though that may be unrelated to the starer solenoid remaining energized.

Thanks!

I just posted a diagram of the combiner relay in the previous reply.

The red lead goes from Terminal 7 of the combiner relay to the ST terminal on my starter switch. There are other leads from the starter switch to the relay: the yellow lead on terminal 4 of the relay likewise goes to the ST terminal on the switch. The heavier gauge wire on terminal 4 goes to the + terminal on the starter solenoid. The blue lead (labeled "43") goes from BAT-A on the starter switch (I believe) to terminal 2 on the combiner relay. Umm... now I'm stumped where that brown lead that I believe is also on terminal 2 goes... but I thought to BAT-B on the starter switch... which doesn't look right....

ASSUMING this is how the yellow and red wires connect to the dashboard starter button, here's how to repair what you've done/mixed up wires.

Remove small-gauge red wire from (7) and move it to the post with the red battery cable (2).

Remove small YELLOW wire from (4) and move it to the post you removed the small red wire from. (7)

Start the tractor.

Post back, please!

I have the same relay on my Kenworth truck tractor. Those2 little blue wires go to a remote starter switch that I added so I could start the motor while I was under the cab. If you short those two terminals, the truck will start.

I put one of those on 8020 many moons ago, it worked great.

Thanks for the suggestion. That's one configuration I didn't try. However, you're indicating there's a simple momentary starter switch in the dash. I still have the original multi-position JD starter switch AR26557, with these terminals: BAT A,
BAT B, LT B, ST, LT A and GEN.

At the moment, the 'external' red lead (on relay terminal 7 in the photo) isn't connected to anything at the opposite end. The yellow lead from the ST terminal on the starter switch currently goes to terminal 4 on the relay.

If it tells you anything, as it is currently configured (yellow to 4, red to nothing) I seem to get 12v to the starter (the relay is not energizing), and after 2 tries the lead from terminal 5 on the relay to the starter is getting darn hot. In fact, when I
went to remove it from the starter the ring connector on the end fell off and the heavy gauge wire itself was extremely oxidized. I'll replace it with fresh copper tomorrow.

Thanks! I can see where one of the blue wires goes to the same terminal as the thin red wire, but the other blue lead is hidden by the battery cable. Where does it connect?

Here is a better picture. You can see the battery cables with two tapes of red and green hook to one battery and the cables with only one tape of red and green hook to the other battery. Then you can see where the two reds and the one green go to the starter.

Shoot, now I see both the blue wires... and they're as obvious in your original pix. I'll give that configuration a try. Thanks!

Unfortunately your remote starter wiring didn't do the trick. I'm back to scratching my head, but thanks!

- David

Capay, I don't know if you didn't see my post linked below, or if you are ignoring me, or don't want my help.

If the latter is the case, let me know and I won't bother you any further.

Otherwise, let's get this thing started.

My understanding is that it worked before wires were disconnected, etc..

There HAS to be +12 Volts to Terminal #7 on the S.P. switch when the key switch is turned to "START" and Terminal 6 must be connected to chassis ground for this to work.

So, 12 Volts will be present between #6 and #7 during cranking.

If interested in my help, check out the thread linked below.

https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ttalk&th=2164252