Testing the Thermostat Cable

The Thermostat Cable connects the Thermostat to the Control Box.

The HEAT/COOL only application requires only Six Conductors.

The COOL/FURNACE/HEAT STRIP,and the COOL/FURNACE/HEAT PUMP models require Seven Conductors.

It is common for most manufacturers to install an eight-conductor thermostat cable.

The cable is easily checked by an ohmmeter.

Disconnect the thermostat cable from the control box and the thermostat.

**Each wire should have continuity from end to end

No continuity should exist between any of the wires**.

Continuity between wires indicates a problem (e.g., a staple) in the cable.

If you don't have continuity end to end on one or more wires you may try using an unused conductor if available.

In some situations there may be a loose connection at a hidden wire harness.