This forum is in read-only mode. Please continue to browse, but replies are disabled for now. Why?

Razor Dune Buggy 36v controller problems

Went to upgrade my sons dune buggy to 36v. 3 12 v batteries wired up. Reads 37.9 v. Purchased the spd-ct660b9, a 36v 500w motor, and the 36 v thumb throttle. Wired it up. The throttle lights up full, but the motor does not run. The motor works when put directly to 36v. Connected the key lock to the on off switch in back and then tried to short the two together. Nothing. What am I.missing here?
This type of problem is usually cause by a problem with the wiring or by a battery pack that drops too much Voltage under load. If you have load tested the batteries and they are ok then it is most likely an issue with the wiring. Sometimes I can solve these kind of problems by simply looking at the wiring. Do you have any way to take a photo of the wiring and attach it to this forum posting so I may take a look at it?


Well, I attached some files.  We'll see if you can see them. So, thank you for the reply.  Let me update you....could not get it to work so I grabbed the 24v thumb controller (original dune buggy), reversed the red and black to match the controller and it worked.  No lights but it ran.  So, I put everything in as I hope you can see and it ran.  Put my son in and 20 sec later...dead.  The batteries and new and fully charged.  I tried to short the key lock but nothing.  

Let's go back a moment to the 36v thumb conttroller..4 wire.  I put red black white on the top row and blue  right below the the white.  Went accd to the wiring listed on your site.


I can see the attached pictures just fine. Thanks for attaching them for me to see. Since the go kart ran for 20 seconds with the original throttle that indicates that everything is wired correctly.

Usually the reason that the go kart would stop running after 20 seconds would be a blown fuse or a loose wire somewhere in the circuit. I would check the fuse for continuity or replace it with a new one, and check the Voltage at the battery pack harness plug to make sure it is outputting 37.9V of power.

The other thing it could be is the brake lever switch if you have it connected. If you do not have the brake lever switch connected to the controller then that could not be causing the problem.

I understand that you shorted the key lock wires together so that eliminates the power switch as being the problem. One of the wires between the key lock connector and the controller has a fuse in it though so I would check that fuse for continuity to make sure that it is not causing the problem.

Regarding the 36 Volt thumb throttle it sounds like you had it wired correctly; red to red, black to black, white to green, and blue to yellow. Since we know that the original 24 Volt throttle is wired correctly right now I would leave it installed until you get it running again, then after it is running switch back to the new 36 Volt thumb throttle and it should work then.

Sometimes fuses look good but they are burned out where you can not see it, so it is always a good idea to test the fuses with a multimeter to make sure they are good. Here is a video I made showing how to test electric scooter and bike (and go kart) fuses.

I hope this helps. If this does not help to solve the problem please let me know.

My apologies...I tested the fuse on the battery which was fine.  It is a 30 amp not know if that was enough of a fuse but the multimeter said it was fine.  I do not have the brake wires hooked in.  The yellow and brown are in those spots from the 24v thumb not know what those wires do.  Tried to take them out and it would not work.  I did not check the key lock fuse...will do was not needed to run the dune buggy from the beginning.  I did test the battery...still 38v.  I had hot glued the battery leads like the original 24v to keep the leads in place.

Finally,  I did recheck the 36v throttle...still no go.  Will update you on the key lock fuse.  I will go back also and recheck all the connects.  Thank you for the input.  

It is possible that the key lock fuse burned out for some reason or became defective after 20 seconds and caused the controller to turn off so I would definitely test that fuse before doing anything else.

OK, let us update....I never had to use the key lock so the fuse status did not matter...I checked it anyway and it was fine.  I noted that when the dune buggy stopped, the power connector stopped sparking when I went to plug it in...and yes, always the last thing I did would be to plug the power in.  No longer sparked.  I was certainly suspicious that the controller fried  or at least was, I ordered another from you guys and lo, it worked!  Including the need to use the key lock.  But, no faster....I read more on the forums and saw that I should use a 24v 500w motor to get to a higher speed.  Just ordered it..  Also, cannot get the 36v thumb throttle to work....should I be using a different throttle?

Great to hear that you got it running. The 500 Watt motor should provide more speed, if it does not then you could change the gear ratio for more speed now that the cart has more power. I am not sure why the new 36V thumb throttle is not working. I can check to see how it should be wired to the controller. Do you know what model the 36V thumb throttle is?

I think the thumb controller was another site... THR-36.  Final updates for you...the bigger 24v 500w motor kick butt!  It then slowed down so I load tested the batteries and one was faulty.  Replaced it and life is good.  Now I will be putting in an order with you guys for #2 sons Dune Buggy for his upgrade....ny particular thumb throttle?  Thanks for the help.  Greatly appreciated

That is great news. It sounds like you have got all of the bugs worked out of the system now.

We have two 36 Volt thumb throttles with battery meters available. One of them (THR-68) only has a battery meter, and the other one (THR-138) has a battery meter and a maintained position on/off switch (switch stays on when pressed once and turns off when pressed again) which could be used for any low power application such as for the key switch connector on the controller so you can turn the Dune Buggy on and off from the handlebars, or for a headlight or something like that.

The THR-138 thumb throttle with meter and switch is better quality than the one without a switch from what I can tell, so you may want to get it instead even if you are not planning on using the switch.

Login or Signup to post a comment