Blower motor stays on...

[1996BLKBauer]

Hey guys, been a while since i've posted. I haven't really been driving my explorer too much because I really need to replace all the ball joints on it, So it has been sitting. I usually try and drive it 2-3 days a week, to keep gas going through it, and to keep the battery charged. Speaking of the battery, it has been going dead, once the truck sits for anywhere from 2-4 days it is literally stone dead, nothing at all. I have a few after market things on the truck, so I pulled some fuses, and unplugged some wires while it sat, but still it dies. On Sunday I go and start the truck up, it started because I charged it all day on Saturday while I cleaned it inside and out. I move it out the driveway park it in the street, play musical cars, hop back in to meet up with some friends, and the blower motor was running on high, so I go and turn it down, turns out that the hvac unit isn't even on? WTF? I turn it on, and I can adjust the speed. turn it back off, and it still keeps going, what is even more weird is that I can turn off the truck, and pull the key out, and it still runs. Now I find it hard to believe that I haven't been able to notice the blower motor staying on this whole time, so I'm going with that it happens randomly though the days that it sits. So for now it sits again, with the blower motor unplugged... just another thing to the never ending list. so does anybody have any idea what could be happening here? I have a few ideas, either the power wire is shorted to battery voltage somehow the whole time, or the the hvac unit is turning it on somehow without being on?

The truck in Question is a:
1996 Explorer Eddie Bauer
5.0L
AWD
Auto HVAC, with Rear controls

***Also I have already replaced the original blower motor about 3 years ago with a good quality one from advanced auto.


Thanks for any input guys, I did a quick search, and didn't find much of anything, just want to pick some brains before I go at it later this week.

 

[Rhett]

Possibly a resistor on the blower motor circuit that's gone out?

 

[1996BLKBauer]

Possibly a resistor on the blower motor circuit that's gone out?

From working on the truck in the past, I am fairly certain that the Auto HVAC does not use a blower motor resistor, I *believe that it is all controlled in the LCD display unit...

 

[bobflood]

Instead of a blower motor resistor, there is a solid state blower motor controller in the same place as the resistor pack. This is what controls the speed.

 

[1996BLKBauer]

Instead of a blower motor resistor, there is a solid state blower motor controller in the same place as the resistor pack. This is what controls the speed.

OK, that makes sense. I'll grab some schematics tomorrow while i'm at work, and start a diagnosis strategy. I really need to get the ball rolling on repairs, that way I can have a reliable truck again, sort of makes me mad it just sitting there , because of stupid little things, and me not having any time to look at it anymore.

 

[bobflood]

Blower motor circuit drives off a fuse that is hot all the time. Runs thru a blower motor relay in a small relay box under the air cleaner box, then thru the blower motor to the blower motor controller, which provides ground to complete the circuit. Quick first test - when the truck is off and the blower still running, reach down and unplug the blower motor controller (below and to the right of the blower motor, passenger side of the engine compartment on the firewall). If the motor then stops, the blower motor controller is bad. Good luck.

 

[1996BLKBauer]

Blower motor circuit drives off a fuse that is hot all the time. Runs thru a blower motor relay in a small relay box under the air cleaner box, then thru the blower motor to the blower motor controller, which provides ground to complete the circuit. Quick first test - when the truck is off and the blower still running, reach down and unplug the blower motor controller (below and to the right of the blower motor, passenger side of the engine compartment on the firewall). If the motor then stops, the blower motor controller is bad. Good luck.

Thanks for the info, if the blower motor controller is bad, that's just a simple replacement, nothing special right?

 

[koda2000]

Correct. Very straight forward repair for the resistor/module and blower motor.

 

[1996BLKBauer]

Very cool, I'm so used to the Newer GM vehicles, where even if you replace a window switch, you need to program it... So it may be a stupid question, but my mind set is on newer vehicles.