If the driver does not light up, first check whether the switch power supply indicator lights up.

• If it does not, troubleshoot as per Switch power supply indicator does not light up.
• If the switch power supply does light up normally, measure the supply voltage to the driver (normally 24V).

1. If the voltage is normal, replace the driver.

2. If the voltage is not, remove all loads on the low-voltage power supply and measure the output voltage of the power supply again.

• If the power supply output voltage is abnormal, replace the switch power supply.
• If the power supply voltage is normal, one or more of the loads are short-circuited. Plug the loads back in one by one to sort out the faulty one(s). Replace any with a new, identical one.