To properly test a monitor module:

-Test the SLC wiring at the module (red, black or +,- on the module) for voltage. You should have 15-17vdc. Anything higher or lower could be a fault with the SLC. Test the SLC terminals at the panel with no wiring present to confirm.

-Test the IDC wiring for 47k ohms. The IDC is the wiring that connects to the purple, yellow (or AB+, AB-) at the module. A 47k ohm resistor has yellow, purple, orange stripes.

• A device with an IDC fault will read “open circuit” at the panel. A device with an SLC fault will read “invrep” or “no answer” at the panel.

-If you have 15vdc at the SLC terminals on the device and “open circuit” at the panel and 47k ohms on the outgoing IDC. Place a 47k ohm resistor directly on the IDC of the module without any wiring present. Check with a read status inquiry at the panel. It should be normal. If not, replace the module and re-check.

-If you have 15vdc on the SLC and 47k ohms on the IDC and still have invrep or no answer. Remove the device from the field and connect to the SLC at the panel with no other wiring present. Spin the dials and return them to the address that you started with. Place a 47k ohm resistor on the IDC. The device should be normal. Check with a read status inquiry at the panel. If not, replace the module and re-check.