Adding a steering servo

Question

I got a Sparkfun Redbot Kit a while back. I ended up building it vanilla and it was a good introduction to the board (the board is basically Uno and a motor shield in one) and the toys that came with it. I figured if could scavenge an RC car, I'd get a more robust redbot. I found an old RC Rock Crawler, it has a basic suspension, two motors, and a steering servo.
Unfortunately, I encountered a problem. The steering servo only has two wires. I loaded the Servo -> Sweep example that is default in the Arduino IDE to see if I could make it work regardless. I tried all the different all the different wire/header combinations on the servo headers:

1. When I attach the wires to gnd and # I get a buzzing noise.
2. When I attach the wires to gnd and pow the servo turns left or, if I swap the wires, it turns right.
3. When I attach the wires to pow and # nothing happens.

I currently can't take advantage of the servo headers on the board (or at least I don't know how to). I was hoping that I could that there might be a work around, I just don't know what it is.
The obvious answer is that I could run both motors off of only one of the headers and use the other to control the steering (thats how the original board from the car was wired), but I can get a faster car if each motor has its own header, and I'm all about the vroom vroom...

I'm running the whole thing off the default 6v (4 AA) battery pack. I might be able to wire in the extra 2 AA's for the extra 3v but I don't want mess with the wiring on the pack unless I know it's going to work.

I have an accelerometer connected to the A4 A5 header block and the motors connected too (I checked w/o them connected but there was no difference).

Image courtesy of https://learn.sparkfun.com/tutorials/getting-started-with-the-redbot
More info on the redbot board https://www.sparkfun.com/products/12097

Answer 1

If the motor you are using has only two wires, and as you described it's response to the direct connection to the power, it can't be a servo. The motor is a normal dc motor. If you want to control the amount of the turns on your rc car you should try to play with the pwm signal, I don't know if it will work or not but at least you will have tried. And remember not to connect the motor directly on the micro's pin if there no motor pins on your red board.