I guess its finally my turn on troubleshooting a Coolster 125cc tao tao. It was running fine until a few days it would not crank at all, like if it was dead, and then attempting again would turn over and start.

The engine does start if attempting to run with directly connecting the battery straight to it.

- The alarm is off
- battery has a fresh charge
- All cables connected, no fried wires or loose cables
- The kids safety plug near the brake light is connected

The problem I am having is the ignition key is in the ON position, Neutral light comes on, but when I press the brake and the starter switch it will not move the starter at all, as if no ignition is ON or had no battery. The strange thing is none of the headlights come on at all. Mine has low beam, which is two lights on each fender, and a high beam, with one main light in the center.

FYI, I will post pictures of the different connectors and troubleshooting so its better to diagnose.

Things I did test and prove to be good
There is continuity when testing with the meter when moving the ignitio switch to the on position. The brake pedal shows continuity when pressing down on it. The kid safety plug also works.

Right now I am checking on youtube on how to get rid off the alarm. Its my atv, I got a title for it, but sometimes less wiring harness and gadgets is better on these chinese atvs. Its minor issue, these atvs are a blast to drive and very reliable. Its been 2 to 3 years and this is the first significant issue, besides the known stock carb, a new one and it runs like a champ.

I am not worried right now about spark because the starter does not even crank. Today is my day off so when I have a chance will take photos of the wiring and upload and see if anyone can shed some light. So far I have not cut any cables or nothing, atv is completely stock.

 

Done, fixed, the black cable on the cdi was slightly not connected on the five plug.

It was barely hanging from the pin. Once that I was there moving cables left and right decided to remove completely the remote box and rear safety strap plug. I am able to turn off the engine from the kill switch only which its fine with me. Cleaned up the ignition housing and re-routed all the cables farther away from the engine.

The atv is finally running again. Might as well buy a spare cdi, ignition key, rectifier, coil etc.

 

whoa! glad you got it going. i 'm just now seeing the post. great job!