DO NOT DISCONNECT THE BATTERY WHILE THE ENGINE IS RUNNING!
That is a sure-fire way to destroy all of the computers on the car, especially if you raise engine speed at the same time. I used to do that every year to show my students the damage that can be done.
If you want to test the system, use an inexpensive digital voltmeter to measure battery voltage while the engine is running. It must be between 13.75 and 14.75 volts.
Test the battery too by measuring the voltage with the engine off. Holler back with those readings.
Monday, February 27th, 2012 AT 11:09 PM