i have a 07 gt mustang n i put a resister plug in it and it work on all 4 speeds n then it stop working on all but high now i really don t know what to do
i really thank yall for ur help

 

no need for a 2nd post on this but anyways the resistor probally popped again, if the blower motor is drawing to much it will pop it. If you have an amperage gauge, test the blower amperage draw while it is mounted in the blower case. Turn on surge amperage could go up to about 28 amps. Amperage draw at high blower should be in the 18 to 24 amp range. The lower the better. Restricted cabin air filter and dirty evaporator core will cause a blower motor to draw more current while reducing air flow volume. These two conditions combined will significantly reduce the life of any blower resistor.

The next thing also would be to get a wiring diagram to test the plug. you would test it with the key on, resistor unplugged. move the switch to low there should be battery power, then move the fan switch to next setting and check the next wire for battery power and so on.If the signal is sent and the relay and remaining wiring is working correctly, the blower motor will work. Assuming of course that the motor itself is good and the is a proper ground at the black wire, terminal "A" of the blower motor connector.