Discussion:
Fwd/Rev, wiring diagram

Nissan 12v diesel fork intermittently doesn't select reverse. Dash lights flashing. Wiring looks OK but I could really use a wiring schematic diagram to better understand the circuit please? Solenoid tests out with ohms resistance on 2 x pairs of wires.
Any pointers would be appreciated.
Also is there any workshop manual PDF available. Brakes and other stuff need doing shortly. Well used model but is an essential forklift on site.

Thanks
  • Posted 8 May 2023 10:21
  • By PetePan
  • joined 8 May'23 - 6 messages
  • New Zealand
Showing items 1 - 8 of 8 results.
That's a good thought about starting in gear. Also there's the reverse beeper to contend with as well. All should be easy enough, perhaps working off the fwd/rev lever contacts and maybe a relay if need be.
Am heading to the yard tomorrow, hoping to hear all is working normal. Let's see.
Thanks for the help. Much appreciated.
  • Posted 18 May 2023 09:57
  • By PetePan
  • joined 8 May'23 - 6 messages
  • New Zealand
Glad you figured it out! And ya that would likley work, only thing i would think could happen is that itll probably be able to start in gear. Other than that itll probably be fine
  • Posted 18 May 2023 09:12
  • By BLey
  • joined 31 Jul'20 - 55 messages
  • Ontario, Canada
Looks like the issue is solved. Some pins of the 4pin connector were seated slightly too deep. Once I remedied that, the forklift has been working perfect for several days.

A big thanks for the good info. It helps a great deal.

This forklift works so hard, surely it's on borrowed time given the age. I wondered what I'd do if the dash unit quit working. Replacement would be non-existent. My thought was to wire the solenoid direct to the fwd/rev switch. Theory says, each solenoid coil would pull about 2amps at 12v. Any reason why that wouldn't work?

Thanks!
  • Posted 15 May 2023 20:03
  • By PetePan
  • joined 8 May'23 - 6 messages
  • New Zealand
Lol, going by the model code it looks like this was sold everywhere except North America, where I happen to be.

I have found somthing saying the codes F-87 reverse solenoid and F-85 as forward with the same descriptions next to them as I mentioned before.

Single speed coil resistance 6.0ohms so your pretty close there at 5.6.

Do the black and white wires change to a different colour on the main harness side? Possibly 2 blacks with a red tracer, a white and a yellow?

https://drive.google.com/file/d/1CBnXPdmnXI2_yUZyC_jQpMV-d7x9n2WU/view?usp=drivesdk
  • Posted 12 May 2023 11:12
  • By BLey
  • joined 31 Jul'20 - 55 messages
  • Ontario, Canada
BLey

Thanks for the thoughts.

Pics here on my Google Drive:
Solenoid..
https://drive.google.com/file/d/1_MG710IMYtTuoPfrkorCa2iX_DuCHTRV/view?usp=sharing

Tag:
https://drive.google.com/file/d/1ylRXcVWlpRglby5eVYEwQcwndNjWIbFK/view?usp=sharing

Will get pic of dash Monday.

It looks like error codes are slightly different for my early Nissan or at least what I was able to find with a search.
F-87: reverse solenoid
F-85: forward solenoid

Only seen one solenoid, right on top. Note 4 wires, 2 blacks, 2 whites.

Yes agreed, of course, once the ecu errors, it would cut feed to the solenoid. Then obviously it will appear dead to probe. Makes sense.

This YL025U does seem to be a bit of a rarity, not many Google hits. However tag does say "model variation" so maybe the real model is something that once appeared on the side panel?
This forklift has had more hits than the Beatles!!
  • Posted 11 May 2023 22:19
  • By PetePan
  • joined 8 May'23 - 6 messages
  • New Zealand
Im not to fimiliar with the older nissan diesels but im sure its pretty close to the newer unicarriers.

F-85 is a code for the forward 1 solenoid.
Below 250mA for 1800ms or above 3.8A for 200ms. Output from vcm is shut off.

F-87 is a code for the forward 2 solenoid for two speed transmissions.
Below 250mA for 1800ms or above 3.8A for 200ms. Output from vcm is shut off.

Wiring for all 3 solenoids should run to the VCM which is behind the RH steps black cover.

Disconnecting the solenoid connector then trying to check for voltage is not possible. VCM will cut power to the connector when it finds a fault and throws a code. Connections should be back probed while connected to check voltage and amp clamp while plugged in to check amperage. Codes will need to be cleared before this can happen as well.

Does this unit have an analog dash or does it have a digital display
  • Posted 11 May 2023 21:14
  • Modified 11 May 2023 21:17 by poster
  • By BLey
  • joined 31 Jul'20 - 55 messages
  • Ontario, Canada
Puzzling this situation through, I attempted to probe the solenoid feed wires. Despite whichever position the fwd/rev control lever was in, I couldn't get a test light to show anything. It was then I found that while the wiring 4pin plug was disconnected to the solenoid, I would then get an additional error code F-85.
  • Posted 11 May 2023 16:16
  • By PetePan
  • joined 8 May'23 - 6 messages
  • New Zealand
Error code: F-87.

Bench test of solenoid: approx 5.6ohms each winding.
  • Posted 10 May 2023 17:56
  • By PetePan
  • joined 8 May'23 - 6 messages
  • New Zealand

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edition #1236 - 26 June 2025
As June comes to a close, the month when our sector recognises National Forklift Safety Day , the United Kingdom’s Association of Industrial Truck Trainers (AITT) has issued a timely reminder of the need to ensure any staff training is fully accredited... Continue reading