That's what Default means........

If these do not find the problem, the next place to look is the wiring at the Resistor behind the drivers headlamp..the wires burn off there after age...it is possible to still have low fan and no high fan if the wire from the relay is burnt at this resistor...but check the other suggestions first...

A rule of thumb on these aux fan circuits is the problem is on the sensor circuit if the relay does not click when the connector is pulled ..but if one hears the relay clicking , but no fan..then the problem is on the Load circuit [ meaning fuse/relay/wiring, or fan motor.]
You know fan motor is fine b.c you have low fan..

__________________
A Dalton