will I get better mileage? (high speed fan)

[DAWSON-MD]

Don't worry, you didn't mess up anything. The multi-function switch doesn't
have anything to do with the fans. The fan switch is on the radiator just
below the lower rad. hose, down where it is difficult to see and even harder
to access. It has a 3 wire connector and it controls the second and third
fan speeds. If you can pull the connector off you will find that one wire
has 12 volts when the ign is on. When the water temp goes up contacts in the
switch close and allow the 12v to go to the 2nd speed fan relay and when
hotter a second set of contacts close to send 12v to the 3rd speed relay.
This 12v signal doesn't actually power the fan, it just energizes the relay.
With the ign on, find the slot in the connector with 12v, use a piece of
small wire to jumper to each of the other slots in turn and you should get
the fan to run at the two different speeds. I end up replacing the
sensor(switch) at all too regular intervals on my 5Ktq. The best way is to
first remove the rad hose completely to access the sensor and use a deep
socket to get it out. After you replaced a few it goes pretty quick. The
last time that I replaced it I took the switch apart to see how it works. A
wax plug pushes on two small rocker arms with contacts on their other ends.
Different length lever arms and return springs provide the two different
temperature settings. The switch can be found at any imported parts store
for about $15. Of course there is the remote possibility that the contacts
in the 3rd stage fan relay have welded themselves together and won't
disconnect regardless of the signal from the switch. If that were the case
the fan would run even if the switch was completely disconnected. I hope
this helps.
Mike
'83 UrQ
'84 4Kq
'87 5Ktq
'77 Ferrari 308 GT4