Looking to install Ecobee thermostat. Only 4 wires coming from unit. Ecoboo has power extender kit but there's no control board on the HVAC unit, so I can't locate a c wire. Any help would be appreciated. Pics of wires aren't great, they're all in the same spot.

One group of wires goes to the fan. Other group goes into smaller main box, took the top off and it's just more relays.

[![enter image description here](https://i.stack.imgur.com/TUdQI.jpg)](https://i.stack.imgur.com/TUdQI.jpg)

Top right wires from thermostat, go down through connector on right. Red turns into blue and goes top left.
[![](https://i.stack.imgur.com/q0zI2.jpg)](https://i.stack.imgur.com/q0zI2.jpg)

Wires to fan.
[![](https://i.stack.imgur.com/Gzu0X.jpg)](https://i.stack.imgur.com/Gzu0X.jpg)

Thx