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M.L. Toys
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Gruber
KidsWheels
Need new batteries? Going from 12V to 18V or 6V to 12V? Wiring Questions?
#128788
I'm not one to break rules and double-post. However, I am doing this re-post at the recommendation of a forum member, Gruber-Power (viewtopic.php?f=3&t=17475):

About a year ago, my son bought his daughter a Kid Trax Cooper S 12V. She loves it. Unfortunately, it now blows the 30-amp fuse every time you press the power pedal. He was going to throw it out, but I'd like to try and fix it. I wish it were a Power Wheels brand. I am not impressed with the Kid Trax quality. It seems very rickety and non-upgradeable. Very few spare parts available, too.

I'm pretty good with mechanical repairs, but not as good with electrical. I could use some insight and assistance. I will tell you what I've done so far and maybe you can give me a next step or two...

I wanted to see all of the wiring and circuits, so I removed the seats and dash and all the wire channel covers. I pulled out the pedal and the shifter. I verified that there are no broken or damaged wires. There are no signs of burning or corrosion. I pulled, cleaned and reconnected each wire connection. No luck.

My first thought was to check the motors to make sure they still work. I disconnected the battery. Then I created a temporary, non-fused 12v +/- jumper cable with 12ga wire and alligator clips. I ran that from the stock 12v SLA battery to one of the motors. It ran fine. It also made the other motor run. I guess that's obvious since they are connected through the car's wire harness. However, I noticed that my jumper wire got REALLY hot. I only ran it like that for about 20-seconds and the jumper wire was too hot to hold by the alligator clips.

I'm guessing that means there is too much resistance somewhere. Is it possible for these 12v motors to run, but still be "bad"? Can they draw so much current as to instantly blow a fuse?

The only other test I ran was to put a 40-amp fuse in place of the 30-amp fuse just as a temporary test. It blew out immediately, too.

Is there anyone on this board with suggestions on how to proceed? I do know that I'll tell my son to buy Power Wheels from now on!

Thanks!
Last edited by MailManX on Wed Dec 10, 2014 10:36 pm, edited 1 time in total.


User avatar
By 12vwiz
#128789
MailManX wrote:My first thought was to check the motors to make sure they still work. I disconnected the battery. Then I created a temporary, non-fused 12v +/- jumper cable with 12ga wire and alligator clips. I ran that from the stock 12v SLA battery to one of the motors. It ran fine. It also made the other motor run. I guess that's obvious since they are connected through the car's wire harness. However, I noticed that my jumper wire got REALLY hot. I only ran it like that for about 20-seconds and the jumper wire was too hot to hold by the alligator clips.
Having the wire harness still connect when testing the motors the way you did still left the foot pedal and shifter switches in the circuit. That means you cant say the motors themselves are what caused the wiring to get hot. You need to test motors only. A internally shorted switch or bad gearbox could cause same issue. So removing the motors from gearbox is recommended.

To avoid cutting the wires going to motors to test them only, unplugging the shifter harness will take switches out of loop.

MailManX wrote:I'm guessing that means there is too much resistance somewhere. Is it possible for these 12v motors to run, but still be "bad"? Can they draw so much current as to instantly blow a fuse?
Yes to both. If the motors alone still recreate issue - replace.

I'm not 100% sure of the wiring in your toy. If you still have problems try posting pictures of wiring layout.
Now is a good time to inspect and service your gearboxes, regardless if they appear fine.
By MailManX
#128838
12vwiz: The motor test is complete. It was successful in removing both motors from suspicion. They ran individually and together with no problem at all. They both had plenty of speed and torque. There was no heat generated in the wiring and none to speak of from either motor.

I guess my next step is to identify whether it's the pedal, shifter or central circuit which is bad. I can't find a circuit diagram for the Kid Trax Cooper S 12v (no surprise there), so I don't know what any of the resistance values should be. 12vwiz, from what I've read on this forum, this type of info is right in your wheelhouse. Can you tell me what the resistance values should be at the various connections? Or, do you already have it written up on a link that I may have overlooked?

Just FYI: I have no intention of modding this car. I just want to get it working again. Since I cannot find replacement parts for it, I will probably have to do some bypass wiring. I want to keep the reverse, but don't care if it loses low-speed in the process.

Here are two exterior pictures of the uncooperative varmint:

Image

Image


This is an overview of the wiring:

Image


The "central circuit", as I have chosen to call it, is between the pedal and the shifter. It has a plug that leads to a dash switch for ON / OFF.

Image


Here is where the wiring leads from the central circuit:

Image


This is wiring from the shifter:

Image


This is wiring from the pedal:

Image


This shows that I cut the wires from the motors to ensure that they were off the circuit for testing. I am an avid 1/10 and 1/8 electric RC enthusiast and do not mind soldering.

Image

Thanks for reading this and for any assistance you can provide. Does the "Bypass Diagram" (minus the accessory circuit) that you posted here apply to my vehicle?
http://www.modifiedpowerwheels.com/foru ... 178#134843
User avatar
By 12vwiz
#128868
No the wiring for the fire truck is totally different.

You're confident that motors are not an issue, Okay good. I was wanting you to unplug the shifter because it gave you direct access to motor wires without cutting them. Not only that, the shifter needs to be unplugged for what's next. I'm simply helping you go through a process of elimination using live testing. Because I do not know what kind of test equipment you have, plus you said your electrical skills are limited....I think it's the easiest for you. If done right you should only blow one more fuse before issue is resolved.

Now, what you're calling "Central circuit" is just a relay (A electrical on/off switch) that is controlled both by the toys key switch (providing a negative) and foot pedal switch (providing the positive). Let's start with making sure it's working then make our way to the other components.

1. Remove both the shifter and foot pedal switches from the wiring harness and connect the key switch harness back up.
2. On the foot pedal plug, connect the red and yellow wires together using a temporary jumper wire.
3. Reinstall the battery to it's original location – fused.

4 through 7....only proceed to the next if all appears well and no fuse blows.

4. Turn key on and off several times while listing for a corresponding click noise coming from the relay.
5. Remove temporary jumper off foot pedal harness and install the actual switch. With the key in the on position push it down several times.
6. Reinstall shifter then activate foot pedal switch several times.
7. Connect the motor wires you cut back together then activate foot pedal switch several times.
By MailManX
#128889
Thanks! That makes perfect sense. I did not get to it today due to numerous honey-do's, but I hope to try it out after work tomorrow. It shouldn't take all that long. I'll let you know how that goes.
By MailManX
#129006
Took me long enough to get to something so quick to do! Sorry about that. You've been very helpful and patient.

Everything was fine till step 5. The foot pedal is the offending switch. It was OK if plugged in put not pushed. But as soon as the pedal is pushed, the fuse pops. Something I found interesting is that it did not matter whether the dash switch was on, off, or even plugged in. I went through a small packet of fuses to test that theory. Even with that switch circuit "open", the fuse would pop the very instant I pushed on the foot pedal.

I was going to take the pedal switch apart, but it appears to be a sealed unit. I posted a photo below. Using the PN from that photo, it seems to be the same switch used on many PowerWheels cars, so I could probably just buy a new switch. However, you may know a better option. I'll await your reply.

Image
Last edited by MailManX on Fri Dec 05, 2014 1:00 pm, edited 2 times in total.
User avatar
By 12vwiz
#129030
MailManX wrote:Took me long enough to get to something so quick to do! Sorry about that. You've been very helpful and patient.
In my neck of woods we call that, life. No worries.
MailManX wrote:Everything was fine till step 5. The foot pedal is the offending switch. It was OK if plugged in put not pushed. But as soon as the pedal is pushed, the fuse pops.

You heard or felt the relay clicking in step 4, good. The jumper I had you put in place of foot pedal switch actually simulated a good switch in the down position. So yeah foot pedal has a problem.
MailManX wrote:Something I found interesting is that it did not matter whether the dash switch was on, off, or even plugged in. I went through a small packet of fuses to test that theory. Even with that switch circuit "open", the fuse would pop the very instant I pushed on the foot pedal.

That's expected. The foot pedal has power on it at all times and is unaffected by key location. When the toy is working the relay only works when it sees both the key in the on position and foot pedal in down position. That feature keeps the relay from killing the battery should the child leave the key in on position.
MailManX wrote:I was going to take the pedal switch apart, but it appears to be a sealed unit. I posted a photo below. Using the PN from that photo, it seems to be the same switch used on many Power Wheels cars, so I could probably just buy a new switch. However, you may know a better option. I'll await your reply.
Yes the power wheels switch has the same function. Before buying lets make sure the foot pedal is the only problem by making the toy function without it. Using the jumper wire will let you do that.
With foot pedal removed and jumper put back in install shifter and run through all its positions. If all is ok remove jumper and connect motors then reinsert jumper with rear wheels of the ground. If toy works the foot pedal is the only issue.
By MailManX
#129055
12vwiz wrote:Before buying, let's make sure the foot pedal is the only problem by making the toy function without it. Using the jumper wire will let you do that.
With foot pedal removed and jumper put back in, install shifter and run through all its positions. If all is ok, remove jumper and connect motors then reinsert jumper with rear wheels of the ground. If toy works the foot pedal is the only issue.
Everything else checked out OK, so I ordered the switch from a reputable Ebay vendor. I cleaned and re-lubed the two gear boxes. I think I'm going to find a way to support them better in the chassis while waiting for the switch to arrive. They just slide into place between a couple of plastic rails and have all kids of slop. It probably doesn't affect anything, but it bugs me.

My granddaughter is excited to know she will get her car back. Thanks so much for all your help. I thank you, my granddaughter thanks you.
User avatar
By 12vwiz
#129056
You're welcome, glad I could help.

Just a tidbit more info: What you're calling "slop" in the gearbox mounting is actually an intended part of the design. By allowing them to move a little actually relieves some stress off the internal gears on start up. Preventing the movement will redirect that harsh energy back to them.
By MailManX
#129057
12vwiz wrote:What you're calling "slop" in the gearbox mounting is actually an intended part of the design. By allowing them to move a little actually relieves some stress off the internal gears on start up. Preventing the movement will redirect that harsh energy back to them.
Thanks for that! I will leave them as is. I am grateful for your knowledge and willingness to share it.
#142352
12vwiz wrote: 1. Remove both the shifter and foot pedal switches from the wiring harness and connect the key switch harness back up.
2. On the foot pedal plug, connect the red and yellow wires together using a temporary jumper wire.
3. Reinstall the battery to it's original location – fused.

4 through 7....only proceed to the next if all appears well and no fuse blows.

4. Turn key on and off several times while listing for a corresponding click noise coming from the relay.
5. Remove temporary jumper off foot pedal harness and install the actual switch. With the key in the on position push it down several times.
6. Reinstall shifter then activate foot pedal switch several times.
7. Connect the motor wires you cut back together then activate foot pedal switch several times.
Hi I'm having this same problem and I followed your steps exactly.thank you for that by the way but the relay never clicked. What can I replace it with? Thank you
#147581
AIRMANSPARKY wrote:
12vwiz wrote: 1. Remove both the shifter and foot pedal switches from the wiring harness and connect the key switch harness back up.
2. On the foot pedal plug, connect the red and yellow wires together using a temporary jumper wire.
3. Reinstall the battery to it's original location – fused.

4 through 7....only proceed to the next if all appears well and no fuse blows.

4. Turn key on and off several times while listing for a corresponding click noise coming from the relay.
5. Remove temporary jumper off foot pedal harness and install the actual switch. With the key in the on position push it down several times.
6. Reinstall shifter then activate foot pedal switch several times.
7. Connect the motor wires you cut back together then activate foot pedal switch several times.
Hi I'm having this same problem and I followed your steps exactly.thank you for that by the way but the relay never clicked. What can I replace it with? Thank you
Hi All, if anyone is still active in this forum I have been searching all over the web for some guidance. I found this thread and thought it might help me. I have a 12v mini cooper that we bought second hand. The battery on the first was a couple years old and I had it replaced. The car was running fine for several months. All of a sudden it is no longer receptive to pushing the pedal. I had the battery tested by the shop and its 100% okay. Ive tested the motors directly with jumpers and they are fine. When the car is disassembled down to the wiring and battery with only the back wheels up on blocks I can get the motors to go by pressing the pedal but eventually they will stop and the relay? starts to buzz/beep at me. I tried bypassing the pedal as the above had suggested and it beeps/buzzes. Is this a sign of a bad relay? Any help would be 100 apprecaited!!

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