Unicarriers (& Nissan) CUMO1L15S:
no negative on fwd/rev contactors

Major problems, have no fwd / rev ground on contactor coil. seat sw, brake sw, fwd/rev selector/ accel sw and transistor board good. also both diodes good. capacitor good, all fuses good. Please; any ideas of where to look next?
  • Posted 28 Mar 2011 00:13
  • Discussion started by Jamie
  • Florida, United States
Jamie
Showing items 1 - 6 of 6 results.
Hi, did you got the service manual? If you so, is it possible to have it?

Let me know,

Thanks
  • Posted 9 Mar 2022 12:11
  • Reply by luis_v
  • Mexico
lvelasco@insercomm.com
I would also like to source a service manual for this model (CUM01L15S)
  • Posted 8 Feb 2017 04:46
  • Reply by Rturner
  • kingston, Jamaica
i have the same model fork as Jamie with the same problem except that the fwd/Rev contact comes in only some times. some times it is out for long periods at a time. need help to solve the problem
  • Posted 8 Feb 2017 04:37
  • Reply by Rturner
  • kingston, Jamaica
Jamie;
Check both negative fusible link in the control panel area that are connected from BV- post. Also check supplimental charging resistor for the + 5V relative to BV- post at the CR board which is mounted under the power cable terminals of the control panel. This has 5 bus terminal all lined up in a row and feed current to the power relays below. Good luck with this 48V cushion tire, 1 ton, standard safety model 1995 blt. truck. Let us know what you find.
  • Posted 28 Mar 2011 23:15
  • Reply by MEngr
  • Missouri, United States
Sorry about that... Model: cum01l15s Serial: 003654
When I engage the key switch, the "green" operator panel is lit. (this bulb was blown), the hand brake is dis-engaged, the direction control is in neutral, the power steering works (easily turns left & right) the accelorator is not engaged and when I place it in fwd or rev nothing happens, no contactor engages. (with the exception of the power steering contactor, with the seat switch activation)
  • Posted 28 Mar 2011 09:13
  • Reply by Jamie
  • Florida, United States
Jamie
you will have to give us more information, like what serial number and control panel is installed.
Usually the negative side of the contactor circuit is "made" with a solid state "driver" module or signal from the logics card, after the card sees all the correct signals in the correct order (seat-switch and ign.switch must close before accel switch etc...)
Please don't consider the negative side of a circuit on an electric forklift to be a "ground" circuit.
first things to check is that all the rest of the "static return to off" (SRO) circuits are in the correct positions and sending the correct signals to the logics circuits
  • Posted 28 Mar 2011 02:38
  • Modified 28 Mar 2011 02:38 by poster
  • Reply by edward_t
  • South Carolina, United States
"it's not rocket surgery"

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