blower fan and relay testing
Find the metal high speed blower relay mounted near the blower motor.
It should have an orange, red, dark blue, purple and black wired plug to it.
Make sure the orange wire is at +12 when fan is on high, Key on test obviously. You may be able to hear the relay click on and off when you switch from medium to high blower speeds if you have two people do the test.
Now follow the fat red wire in the harness out to near the antenna area near the inner fenderwell area.
Should be a connector there with the fat red wire passing through it.
Usually it's corroded or melted there and can be bypassed by joining the two fat red wires together if need be.
Wiggle it and see if the blower works on high.
That is the high power +12 feed from a fusible link directly so it should be HOT at all times (+12) so don't short it to metal, if it isn't live there the fusible link could be bad down at the starter.
orange wire to the relay which switches the relay so that voltage now comes from the fusible link to the relay and on to the blower motor. Check the relay to see if there is battery voltage at the relay on the orange wire when the switch is on High. If there is not, follow the orange wire back toward the inner fender and find the connector. 99.9% of the time, this connector is smoked and is no longer making a good connection. Fix it if this is the case and you should have High speed. If you had power at the relay, then check the red wire at the relay which comes from the fusible link to see if it has power. If it does not, replace the fusible link. If it does, change the relay.
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