So I picked up this little truck, and the blower motor does not work correctly. There are 4 settings, Low, Med-Low,Med-High, and Max. The issue is Low, Med-Low, and Med-High ALL act like Low. Max works like Max.
So research tells me it is the resistor block for the blower motor. So I change that. Still works the exact same. More research tells me the plug going into the Resistor block often gets corroded and faulty, so I change that. Still works the exact same. More research says sometime the switch in the cab goes faulty. I replace that. STILL WORKS THE SAME.
From what I understand from the schematic, on Low, the switch just goes to ground, and the current goes through all 3 resistors on the resistor block, providing max resistance and lowest fan speed. When you select Medium Low, the current goes to the Med Low wire going into the resistor block, and then through 2 of the resistors, and the fan goes faster. Med Hi send the current to the Med Hi terminal on the resistor blow, which only ha 1 resistor in front of it, and you get even faster fan. Max bypasses the resistor altogether and you just get max power to the fan.
But for some completely unknown reason, Low, Med Lo, and Med Hi ALL act like low. Max works like Max, since that bypasses the resistor block.
Here is the schematic
https://file.io/YCa0gpeJGjP7
Someone in a Ranger forum said this:
But I have no idea what to do with that. Even with everything replaced, Lo, Med Lo, and Med Hi are ALL grounding to G105.
Any ideas what I should test next? From the wires I can see, I don't see anything cut, spliced, or tampered with to cause a short to the G105 ground. And I have replaced the resistor, plug, and switch.
So research tells me it is the resistor block for the blower motor. So I change that. Still works the exact same. More research tells me the plug going into the Resistor block often gets corroded and faulty, so I change that. Still works the exact same. More research says sometime the switch in the cab goes faulty. I replace that. STILL WORKS THE SAME.
From what I understand from the schematic, on Low, the switch just goes to ground, and the current goes through all 3 resistors on the resistor block, providing max resistance and lowest fan speed. When you select Medium Low, the current goes to the Med Low wire going into the resistor block, and then through 2 of the resistors, and the fan goes faster. Med Hi send the current to the Med Hi terminal on the resistor blow, which only ha 1 resistor in front of it, and you get even faster fan. Max bypasses the resistor altogether and you just get max power to the fan.
But for some completely unknown reason, Low, Med Lo, and Med Hi ALL act like low. Max works like Max, since that bypasses the resistor block.
Here is the schematic
https://file.io/YCa0gpeJGjP7
Someone in a Ranger forum said this:
When key is on and Mode/Vent switch is in any position except OFF, the blower motor gets 12volts
The resistor block is always Grounded by its black wire(G105), but thru 3 resistors, which would be Low speed
If the speed knob in the dash was set to med. low then resistor block has a NEW ground path and only thru 2 resistors, so higher fan speed than Low, NEW ground path uses G201 in the cab
Med. high changes to NEW ground path thru 1 resistor, so even higher speed, also use G201
High speed by-passes the resistor block entirely, no resistors, it's a direct ground for blower motor, via G201
So if low, med. low, and med. high all seem to be the same speed, then med. low and med. high wires, or switch contacts, are not giving a NEW ground path in resistor block
The resistor block is always Grounded by its black wire(G105), but thru 3 resistors, which would be Low speed
If the speed knob in the dash was set to med. low then resistor block has a NEW ground path and only thru 2 resistors, so higher fan speed than Low, NEW ground path uses G201 in the cab
Med. high changes to NEW ground path thru 1 resistor, so even higher speed, also use G201
High speed by-passes the resistor block entirely, no resistors, it's a direct ground for blower motor, via G201
So if low, med. low, and med. high all seem to be the same speed, then med. low and med. high wires, or switch contacts, are not giving a NEW ground path in resistor block
Any ideas what I should test next? From the wires I can see, I don't see anything cut, spliced, or tampered with to cause a short to the G105 ground. And I have replaced the resistor, plug, and switch.
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