Hello,
I bought an Expert on board glw driver unit and it does not seem to send enough current to the glow plug to become red. I have removed the plug from the motor and held it very tight against the motor and viewed the element. I connected it as per instructions and I use a 4.8 V 600 mah battery. What may be the problem ? This is the second unit I am trying. The first one did not light the glow.

Thanks