JCB 214 (3CX) No Forward/Reverse/Start

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br2an
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Joined: Sat May 23, 2015 2:52 pm
Real name: Brian Alexander
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Re: JCB 214 (3CX) No Forward/Reverse/Start

Post #11 by br2an » Sat May 19, 2018 5:45 pm

Just back from more testing and a bit more info.

My understanding of relays and how JCB implements them was wrong. Apparently JCB fuse protect their switch wires and load wires off the same fuse. I thought the fuse feeding the switch wire was simply toggling the relay off/on as this is all I have ever come across working in automotive. If CAT or John Deere wire same as JCB somebody please advise as it must be a heavy equipment thing. This 10A fuse actually supplies power to the first and second relays (mentioned above) and ultimately the reverse Hi/Low solenoids (for reverse gear).

Once I got it in my head to look beyond the relays, the solenoids became obvious. I also thought to try different gears in reverse which led me to discover reverse 2nd and 4th work but reverse 1st and 3rd blow fuse.

Next step: determine which of the two reverse solenoids are used to shift 1st and 3rd gears and then troubleshoot that solenoid. My guess now is that the solenoid has failed with an internal short but I still need to disconnect the solenoid and test for a wire short between relay and solenoid.

I took a picture from under the machine of the solenoids. Looks like three pairs, can anyone point out in the picture which pair is Hi/Low Reverse? Also any tips on how to remove? Looking into my manual now but any tips would be appreciated.

Thanks,

Brian


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Topic author
br2an
Posts: 9
Joined: Sat May 23, 2015 2:52 pm
Real name: Brian Alexander
Has thanked: 1 time
Flag: Canada

Re: JCB 214 (3CX) No Forward/Reverse/Start

Post #12 by br2an » Tue May 22, 2018 1:35 am

Well, success at last. Aside from a week of tracing wires and head scratching it turned out to be a simple chafed wire. Very cheap fix:)

The loom containing the wire going to the Rev/Lo solenoid was resting on top of the transmission cross member and chafed the insulation off one wire. It did not come from factory like that so I assume somebody working on the machine previously didn't take the time to put things right. I attached a plastic connector just before the chafed spot to the cross member using a zip tie so it will not cause any more grief in that spot again.

I also took some time tidying up some of the harness under the console and had a look around underneath for any potential problem areas. Hopefully I didn't miss anything but only time will tell.

I'm not sure how professionals do this but I spent at least twice as much time studying schematics and getting my head around how the system works versus actual working/testing on the machine. As mentioned earlier, once I realized the relay's main power and switch trigger are fed from the same fuse the solenoid and harness became the obvious place to look.

I ran it today for about 4 hours after reassembling everything and all is good.

Thanks to all who helped, hopefully this can help somebody else down the road.

Brian


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