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RC3020 Troubleshooting : No FWD/REV
Having trouble with my residential workshop RC3020. I have spent 12 hours toning out wiring throughout the lift with every access panel and plate removed.

My FWD/REV performance has gone from intermittent to absent. Batteries at 38.6V; Amperage good; fluids good -- before your ask ;-) I was able to get "some" movement if I unplugged the batteries and inserted. Sometimes it operates, sometimes a single side of the FWD/REV solenoid clicks. If this happens then I need to unplug/plug to get flow.

At this point, I have performed the following diagnostic steps:
verified main power solenoid function
verified that all connection solenoids operate correctly with 24V
chased all signal wires/leads from solenoid to ECU
ohm'd the micro switches on the control stick

The lift and tilt are still working fine. The steering drive is operational.

What am I missing? At current, the only solenoids operating are the main power solenoid and the hydrolic pump solenoid. I'm not hearing or seeing the other solenoid/switches operating. I "think" I'm only getting 18V to these solenoid/switches.

Other tips from people far smarter than I?


  • Posted 4 Jan 2012 08:43 AM
Total replies: 18. Showing items 1 - 18 of 18 results.
check pot and forward reverse switches does this unit have a lx card can you get your hands on hand set

happy forker
  • Posted 8 Feb 2012 01:16 PM
Truck has a set of contactors for each drive motor. For them both to be powered, the steered tire must be within 30 degrees of straight. I would check or replace the floorplate or deadman switch first. I have seen some resistance in this switch allow the power steering to come on, but not the travel. The next switch to check is the one under the brake pedal. The third and fourth switches would be the forward and reverse switches. These operate off a cam when you move the control handle. I would also check the two 140 amp fuses on the contactor panel. One is for the left drive motor, and one is for the right. If you have the steered wheel turned to the left of right, and one drive fuse is open, you might not get the contactors to pull in. The motor controller will sense an open circuit and not allow travel. I would also check to see if you have any contactors welded or stuck. The 1A, or high speed contactor being welded will prevent travel. Pull all the plugs from the EV100 control card and make sure all the female pins are fully inserted. They must be in order to contact the male pins in the control card and allow travel. There are two switches on the steer wheel assembly that open as you turn left or right that you can check. The last resort is to call a lift truck repair company. Most will have a handset you can plug into this to do some diagnostics. If they send someone out, make sure to tell them they need to bring a EV100 LX hand set. Many brands of lift trucks used this GE motor contoller such as Clark, Mitsubishi, Komatsu, Hyster, Yale, Caterpillar.
  • Posted 9 Feb 2012 02:17 PM
check the connections at the z connector at the logics. also check the inputs the the terminal board on the card. You need a good pot sweep and the other inputs need to be satified as well. don't forget about those stupid steering switches everyone gets burnt by those.
  • Posted 15 Feb 2012 04:36 AM
  • raul_s
  • San Luis Potosi, Mexico
Try desconecting a wire from a fw or rw contactor. If the truco work, you have a detective card.
  • Posted 25 Feb 2012 11:16 AM
This seems like a problem I just started having with our RC3020. Drive motors will run intermittently. Took all panels off to expose components everything seem intact. Contactors pull in sometimes it will go sometime not. Does the foot petal control anything as far as current getting to the motors after the contactors pull in? How do you know when to replace the brushes in the motors. Any more suggestions on this one? Thanks
  • Posted 5 Sep 2014 12:44 AM

Sounds like directional switches or the traction pot all located by the handle. Check those out. How does it do with plugging? usually failing to plug is a symptom of bad switches/pot.

Motor brushes need to be replaced when the top of the brush is even or just below the brush holder. If you replace them make sure to blow the motor out with compressed air. That should be done pretty regularly.
  • Posted 5 Sep 2014 11:14 AM
  • • Modified 5 Sep 2014 11:14 AM by poster
Adam The Tech-Thanks for the reply. Brushes look ok - blew a lot of dust out, charged the battery with equalizer feature, checked switches/pot. Still having the problem. If the contacts pull in could it be the directional/pot switches? What do you mean by plugging? Also noticed when having the problem it will move again after turning the steer wheel and/or turning it off then back on. Any ideas? I'm not the smartest guy when it comes to testing electrical components. Thanks for any help.
  • Posted 6 Sep 2014 12:38 AM
  • kevin_t
  • Pennsylvania, United States
Check your brake and floorboard switches,sounds like one is out of adjustment,will be under the floor plate you stand on...
  • Posted 6 Sep 2014 01:16 AM
That was also another thing I had done. The switch under the brake pedal was loose and I thought that for sure was the problem but that didn't solve it. What's the best way to make sure the switches are good? Thanks kevin t
  • Posted 6 Sep 2014 03:32 AM
A Bad pot or directional switches will still activate the contact unless the switch is completely gone and doesn't make a connection when the switch is closed. Basically, a bad switch will either be making a poor connection when the switch is pressed forward / backward OR some sort of bad connection when its not being pressed. This is sending bad voltage reading to the controller and either codes out and does not move or reacts erratically. Example: Driver pushes handle to go forward but the bad forward switch has high resistance not allowing the exact voltage to reach the controller and... confuses it coding out and not allowing you to drive. Or, driver pushes handle forward but the revers switch is bad also making a connecting, again, confusing the truck. If the pot is bad or the pot and switches are out of adjustment, the switches could click before the correct voltage is being sent by the pot. I'm sure there is a better, more scientific way to explain all that! Hope it makes some sense...

Plugging is when you make the truck go in the opposite direction to slow down the truck. Your driving forward the you throw it in reverse to slow the truck down and go in the opposite direction. If you are driving forward then plug in reverse to slow down but the truck just continues to "coast" forward this is a switch/pot issue. Usually the plugging and issues you described above are related.

Bad brake switch could be the problem as well. The truck wont move because the switch is telling the truck there is no drive yet, don't move. The brakes probably aren't the issues. If the brakes were not releasing the truck would just struggle to move because the brakes were still on. Your truck just isn't moving at all. Check the brake switch and make sure when you step on the pedal you can hear the switch click. you can adjust it if its not.

So, when one of these things fail the truck codes out, even though there isn't a wrench light on the dash for you to see and restarting the truck clears it to try again. I really really think its those directional switches or pot. I've seen it too many times on the RC3000.

Testing the switches: Remove one of the wires from the switch. Put your voltmeter on ohms. connect your leads to the terminal you just removed a wire from and the one still with a wire. When the switch is open(not pushed in) you should get OL or a really really high number depending on your meter. If switch is open and is reading a low resistance the switch is bad because it is allowing a connection when it should be open with no connections. Next, push in the switch with your leads in the same place. When the switch closes you should be getting a low resistance. like.2 ish ohms. try wiggling the handle with it close to simulate the truck bouncing on the floor and open and close it fast several times to make sure it goes from a solid open OL to closed with a low resistance. Do this on both switches. Again.... Im sure there is a better more scientific way to explain all that but hopefully it will get you some where!!!

The POT. put your meter on DCV and place the leads on the center pin of the pot and either of the other two pins. With the truck on BUT YOUR FOOT OFF THE PEDAL so you don't go driving off unexpectedly... at rest the handle should be, I think at around 5V. going in either direction it should count down to around 0 volts. make sure your getting about those reading. Moving it slowly you want to make sure the voltage changes smoothly and doesn't jump around. You can check it with ohms too but I dont remember all those details right now.

Be safe when working on this stuff. You should probably jack the truck up and block the drive tires off the floor. Also when checking the switches be careful to avoid laying your screwdriver over the capacitor to your right. You don't want to let the insides of that thing out!

Good Luck! Let me know what you find!
  • Posted 6 Sep 2014 04:10 AM
  • • Modified 6 Sep 2014 04:11 AM by poster
I will be checking these out next week. It seems to plug alright, I usually try to use the brake when changing direction. Right now the forklift is parked in a straight isle and checking it out going in a straight line only it works fine both forward and reverse. It cuts out when turning slowly. Thanks for your input AdamTheTech.
  • Posted 6 Sep 2014 09:15 AM
The easiest way to check a switch is to put digital VOM leads across the switch terminals. switch. Operate switch if any voltage observed, switch is bad. Do not use ohm meter to check switch. Check term 1 at card, upper left screw term. Pos. lead. Neg. lead at batt. neg. Key on. you should have 5 volt with smoothly decreasing voltage as you move control handle F/R. Terminal 5 or 6 should have voltage with F/R activated. Term 3-4 should be batt voltage. T2 SCR panel should have 1/2 batt. volt.
Steer switches under truck by steer wheel need to function properly. Not just click. they must work electrically. Wiring runs up under entry switch bracket and up to TB 2 at top of contactor panel.
fixitfast- if you turn steering and motor contactor pulls in and turn the other way you only have one motor running. Steer switch not working properly. Maybe damaged.
Check plugs at bottom of panel. Clean all connections with DeOxit contact cleaner. Remove Power fuses to check properly.
Don't forget PS steer switch is in the drive circuit. Brake sw. and power steering sw. are both needed to closed to travel.
  • Posted 8 Sep 2014 07:33 AM
  • • Modified 8 Sep 2014 07:49 AM by poster
Thanks for all the input from those who know more than me about electric forklifts. All this has been helpful information. Thanks again to all who took their time and responded.
  • Posted 8 Sep 2014 11:55 AM
I think I fixed my problem. After checking all the switches and jacking drive and steer wheels off the floor I found out that only one drive wheel was driving and when I turned the good wheel would cut out. I took the main drive contactor out and cleaned it up (it had a bit of pitting and carbon build up on the contacts) put it back in and everything seems to work. I be taking out the other contactor next and doing the same. Happy forking!
  • Posted 11 Sep 2014 06:37 AM
  • edward_t
  • South Carolina, United States
I would suggest that you just go ahead and replace [as a complete unit] the directional contactor assembly. once you start trying to "clean them up" you will be at it forever. and the assembly usually costs about the same as your labour to go go back the 2nd time.

"it's not rocket surgery"
  • Posted 11 Sep 2014 09:27 PM
Thanks for the advice Edward. I was planning on replacing the directional/pot switches and was wondering where is the best place to buy parts at a reasonable price.
  • Posted 12 Sep 2014 02:31 AM
Hi Adam the tech , I own a Crown RC3020 -35 and have started to get a weird problem the machine when in forward starts clicking in and out and at points stops working , this just started , have not used it much this winter and when I started using this truck its acting up. when in forward you can hear the forward relay clicking in then it bounces in and out / Open then closed but then works ok again then in and out then sometimes stops moving in forward , let know what you think might be the problem , I was thinking it might be the potentiometer under the joy stick but not sure ,
  • Posted 17 May 2018 12:57 PM
  • LP35
  • Quebec, Canada

i have the same issue. how did you manage to fix your problem?

thanks for the reply
  • Posted 24 Jul 2019 12:59 AM
Total replies: 18. Showing items 1 - 18 of 18 results.

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