Check the alternator voltage. Access SYSTEM MEASUREMENTS mode by pressing and holding ENTER, 0, and 2 keys. Continue holding ENTER and 0 keys while releasing the 2. The unit will beep once and SERVICE SETTINGS will appear on the display. Release the ENTER and 0 keys. Press the 8 key. The message MEASUREMENTS will display. Use the SCROLL key to select ALTERNATOR VOLTAGE. Begin pedaling and verify the voltage is between 10.5 and 13.5 VDC. If voltage is not correct, gain access to the lower control board and place the red lead of your voltmeter on test point TP8 (FIELDDRV) of the lower control board and the black lead of your voltmeter on the test point TP11 (AGND). Then access the MANUAL MODE (from SYSTEM MEASUREMENTS, press ENTER key to return to SERVICE SETTINGS. From the SERVICE SETTINGS press ENTER key to return to MANUAL mode.) In MANUAL mode, press the SCROLL key until the speed is displayed. Pedal the unit at 1.5mph. Verify on your voltmeter voltage is 5.5 – 6.5 volts. If voltage is not correct, replace the lower control board.
Check the voltage at the alternator by placing the red lead of your voltmeter on the alternator yellow wire/nut and the black lead on the alternator black wire/nut labeled "E". Verify voltage is 9 – 10 VDC. If the voltage is correct, replace the alternator.
Check the voltage between the alternator and the lower control board. Place the red lead of your voltmeter into the yellow wire at the J4 connector of the lower control board and the black lead of your voltmeter on the alternator black wire/nut labeled "E". Verify voltage of 8 - 9 VDC. If the voltage is not correct, replace the wire harness.