Originally Posted by Zulfiqar

swapping in a HS relay wont help if the wiring is burnt on the resistor.

Arthur's post above has one very important piece - remove the blue coolant sensor connector to cause the HVAC module to kick start the fans to full speed immediately when the key is switched on. That test basically gives you the quickest way to confirmation of the wiring. e.g. if fans dont start, use a test lamp to see where the power is missing.

e.g. resistor leg, relay fuse, etc.