blower motors stays on

[pullinpower350]

I have a 1995 explorer eddie bauer edition. one day i came down the road near my house when the blower motor came on by itself. it has climate control in this explorer. i called for and they said it was a special resister that went bad. so i bought a new one and it didnt help. so i looked throught all the wire looms for a short, none. i know the resister works off a ground and this resister has the blower motor relay build it. does anyone know what to do or has it ever happened to anyone else. also if you shut the key off the motor still runs. so i've been pullin the fuse out.

[shorod]

Does the blower seem to be blowing on high speed the whole time? If so, it sounds like maybe the blower motor relay is stuck, or the coil is being energized all the time.

If the high speed relay is part of the resistor as you mention, and you replaced the resistor/relay, then you'll need to check the relay coil drive circuit to determine if the relay coil is receiving ground all the time. If so, you'll need to trace the signal back to the blower motor speed select switch. You'll probably want a wiring diagram for this.

Since you have an Eddie Bauer, do you have the electronic automatic temperature control? If so, you're right, the blower motor controller does have the high speed relay built in. If there isn't a wiring fault, you'll almost need an oscilloscope to determine if the signal from the control head is the problem. Or, you can shot gun out the control head with a used one of of eBay.

-Rod

[pullinpower350]

The only thing is i cut all the wire to the resister other than the ground and power. There is no relays between either the ground or power. the ground goes right to the frame and the power comes for the power distrubtion box no relays or anything in between.Does one of the three wire either ground it out when the control panel is off or does it send low voltage to the resister to turn it on or off.

[shorod]

I don't have the wiring diagram for the 1995 Explorer, but I would expect that battery voltage is applied to the positive lead of the blower motor with the key on and the air selector set to anything but off (panel, mix, floor, A/C, or defrost).

The ground is actually what's switched for the blower motor. With the blower switch set to "High" the motor has a direct path to ground. With the fan speed switch set to one of the lower speeds, the current through the blower motor is limited by the resistor that is switched in.

-Rod