RC3020 Troubleshooting : No FWD/REV - Crown

22 Jul.,2024

 

RC Troubleshooting : No FWD/REV - Crown

Having trouble with my residential workshop RC. 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? Thanks! /jm

Link to Felici

Hi

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

thanks for the reply

  • Posted 24 Jul 00:59
  • Reply by LP35
  • Quebec, Canada
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Hi Adam the tech , I own a Crown RC -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 12:57
  • Reply by rwksurplus
  • Michigan, United States
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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 02:31
  • Reply by fixitfast
  • Illinois, United States
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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.

  • Posted 11 Sep 21:27
  • Reply by edward_t
  • South Carolina, United States

"it's not rocket surgery"

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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 06:37
  • Reply by fixitfast
  • Illinois, United States
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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 11:55
  • Reply by fixitfast
  • Illinois, United States
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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.

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  • Posted 8 Sep 07:33
  • Modified 8 Sep 07:49 by poster
  • Reply by oldmanforklift
  • Arizona, United States
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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 09:15
  • Reply by fixitfast
  • Illinois, United States
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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 RC.

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 04:10
  • Modified 6 Sep 04:11 by poster
  • Reply by AdamTheTech
  • North Carolina, United States
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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 03:32
  • Reply by fixitfast
  • Illinois, United States
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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 01:16
  • Reply by kevin_t
  • Pennsylvania, United States
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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 00:38
  • Reply by fixitfast
  • Illinois, United States
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@fixitfast

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 11:14
  • Modified 5 Sep 11:14 by poster
  • Reply by AdamTheTech
  • North Carolina, United States
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This seems like a problem I just started having with our RC. 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 00:44
  • Reply by fixitfast
  • Illinois, United States
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Try desconecting a wire from a fw or rw contactor. If the truco work, you have a detective card.

  • Posted 25 Feb 11:16
  • Reply by raul_s
  • San Luis Potosi, Mexico
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Man Lift Rental

I used to work for a major aerial lift manufacturer. Most of the accidents referenced above have to do with either driving while elevated and going off a curb (hard to judge the ground elevation changes from way up in the air), or having the heavy self-driving machines (not the lighter towable ones being discussed here) driving over an underground void (stormwater tank, septic tank, or other hidden void space underground) and dropping a tire in, which will definitely cause a fishing-pole-type whipping of the extended boom which of course can lead to a serious injury accident.

The self-driving boom lifts are extremely heavy due to the counterweight on the machine - my plant made 20' to 34' lifts, and we had counterweights in the 8K to 16K pound weight range - that was just the counterweight, not the total machine weight which was much higher. You can have a very high point load of 5-6K pounds of weight on less than a square foot of tire contact area under one corner of the machine, so this is what can cause failure of hidden underground structures that were not designed for that kind of point load (like a plastic drainage culvert buried a foot deep).

If you use common sense, 99.7% of lift accidents can easily be prevented. The trailered boom lifts have outriggers and self-leveling systems. Depending upon your soil conditions, you may want to install wooden blocks/pads underneath the outrigger feet to distribute the force over a wider area. Use your own judgement and common sense here - if you deploy the outriggers and a pad pushes into the soil a few inches or more, well durr, better widen the pad's footprint!

I would not hesitate to use such a machine at all myself; I did extensive field testing of our products as do all lift manufacturers. Based upon your described situation I believe that you have correctly chosen the right tool for the job. Trim up any trees on your property and clean out your gutters while you have the machine as well!

 

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