Join Date: Aug 2009
Location: Gaithersburg, MD
According to the wiring diagram I have, the power is always supplied, provided the relay 30 is energised. The ground is controlled via the switch on the HVAC control box (center dial) and the blower resistor. So first question is how you are measuring ground? Because if the dial is on (but not high/full speed) there will be resistance to ground via the blower resistor. If on high, that takes a different path through the high speed fan relay.
If we assume for a moment that you ARE measuring correctly, the one point of failure - other than what you've replaced - is the fan speed switch, or the connector to it, behind the HVAC controller box.
Owner of "Campbelle", a Brazen 2008 GXP ... with mods piling up...