Free Thermostat Troubleshooting Guides

Fix Your Thermostat
Without Calling an HVAC Tech

Expert step-by-step guides for Nest, Honeywell, Ecobee, and more. Diagnose the problem, fix it yourself, and save hundreds on service calls.

Guides by Brand

Find troubleshooting and repair guides specific to your thermostat brand.

Thermostat Wiring Made Simple

Don't let tangled wires intimidate you. Our color-coded wiring guides show you exactly which wire goes where — whether you're installing a new thermostat or troubleshooting a wiring issue.

  • R, W, Y, G, C, O/B wire color codes explained
  • Heating, cooling, and heat pump wiring diagrams
  • What to do when you don't have a C wire
  • Brand-specific wiring differences

Common Wire Color Codes

R (Red)Power — 24V hot wire from transformer
W (White)Heat — controls heating system
Y (Yellow)Cooling — controls AC compressor
G (Green)Fan — controls blower fan
C (Blue)Common — completes 24V circuit
O/B (Orange)Heat pump reversing valve

Why Homeowners Trust ThermostatFixer

Easy-to-Follow Steps

Every guide breaks down complex HVAC problems into simple, numbered steps anyone can follow.

Safety First

Clear safety warnings and "when to call a pro" guidance so you never put yourself at risk.

Brand-Specific Guides

Not generic advice — detailed guides for Nest, Honeywell, Ecobee, White-Rodgers and more.