childrens remote controlled car

hello everyone! it has been a while since i last posted here,but i am stuck and hopefully you guys can help me out. my son has a 6v motorized toy car(for riding) which can be controlled by a remote control. the problem is that the car has no power for minimum hills climbing(6v) so i went out and bought a 12v battery after i checked that the car's motor will support 12 volt feed. the car can be driven manually or with a parent operated remote control mode as mentioned and it can also drive back and forward(makes sence by now doesnt it:) make a long story short i have 2 wires that connects to the electric motor when they obviously change polarity according to the direction in which the car is going. i cant figure out a way to add aditional relays which will be driven by the 2 6v wires that supposed to be connected to the motor and connect a 12v to the common terminal. the aim is to get the motor to be driven with 12v power and keep all the car's operational methhods active(forward,reverse,manual,remote control operated). hope i explained it properly(sry for the bad english) any ideas? thanks ahead, rami. btw i cant just replace the 6v battery because the remote unit cant be operated with 12v.

any one please??

I will take a guess as to how this could be resolved. There has to be a relay or contactor that powers the motor. Or possibly two relays, one for each power lead from the motor. You need to find the INPUT power (and ground) to these relays. This would be the point to connect your 12 Volt + for the motor. You have to determine where the control circuits, radio receiver, etc get their 6Volt +, and be sure this voltage is isolated from the 12Volt. Begin at the motor, and work backwards to find the relays. If you find the right connection for the input for the motor power,and leave it disconnected for testing, you should be able to work the controls and hear the relays click. I'm guessing that the motor relays leave both sides of the motor at ground (battery negative) at rest, and energize one side at a time to (+) for operation. Find this point in the circuit to connect your 12V to, leave everything else at 6V; I think this is what you're trying to do. Good Luck.