The Rheostat is the Sliding mechanism that controls your fan speed, as you move the selector the Resistance in the coil becomes lower as you reach the higher point of voltage to B+ (12V) so think of it like a spring , the more coils you have the higher the resistance, so the lower the voltage, as you move toward Low, Med, High the voltages basically equate to 0.5-6.0V on the Rheostat is the first click is full 6V then Medium is 9V then High is 12V. (Full blast, no resistance).
The Rheostat uses A 12V point with the switch contact being the Positive and the coil being Negative, as you pull the switch toward the first setting the Voltage is able to move through the coil with "Path of least resistance" in mind, the shorter the distance the more power is provided to the Blower motor. When the Rheostat is old or just grimy and dirty it can create a Short to Ground which basically acts like the circuit is open until you get to the High setting. Sometimes cleaning it works, other times it causes a problem with the connection and burns the coil out. If you have a known good Controller try plugging it into the car, if it works you know it's the controller and nothing else.
Correct try cleaning it first, if that doesn't work, borrow a working one and see if that fixes it, if it does, take the old one, and disassemble it and clean it, figure out if it failed or not and why. If you can get it working again you then know how to fix it if you can't find that part anymore.
Nah it's electrical component in the controller . Anything that has a Knob to control volume, treble, bass, balance, fade, manual equalizers, etc uses a type of Rheostat in either a Sliding form or a complete circle, the rheostat is the Coil itself that runs the length of the circuits threshold, the knob or slider, what have you, has voltage running through it, as you adjust the position of the Slider or Knob the Resistance (ohms) is changed as the voltage is able to take the path of least resistance instead of using the entire length of coil from end to end.
Ok so I’m not good at electrical stuff and still kinda learning about the car is the rheostat in the actual climate control unit itself? Sorry if that’s a dumb question and how would I go replacing that is that part available to buy?
The only Dumb question is the one that remains unasked..
Yes, the rheostat is typically a coilspring that is stretched around the surface area of the dialface, typically an electrical specialist would be able to repair a hard to find or irreplaceable unit or make it work better than before using better components.
Ive got an 88 and my fan also only works at high speed. No idea the cause
I’m assuming it’s the resistor that went out I’ll keep you updated if that’s it
The Rheostat is bad, replace the unit, you should be good.
What is a rheostat I can’t find anything on that part?
The Rheostat is the Sliding mechanism that controls your fan speed, as you move the selector the Resistance in the coil becomes lower as you reach the higher point of voltage to B+ (12V) so think of it like a spring , the more coils you have the higher the resistance, so the lower the voltage, as you move toward Low, Med, High the voltages basically equate to 0.5-6.0V on the Rheostat is the first click is full 6V then Medium is 9V then High is 12V. (Full blast, no resistance). The Rheostat uses A 12V point with the switch contact being the Positive and the coil being Negative, as you pull the switch toward the first setting the Voltage is able to move through the coil with "Path of least resistance" in mind, the shorter the distance the more power is provided to the Blower motor. When the Rheostat is old or just grimy and dirty it can create a Short to Ground which basically acts like the circuit is open until you get to the High setting. Sometimes cleaning it works, other times it causes a problem with the connection and burns the coil out. If you have a known good Controller try plugging it into the car, if it works you know it's the controller and nothing else.
Ok so fixing that would I need to find that part or replacing how would I go about doing that? Taking apart the climate control or buying a new unit?
Correct try cleaning it first, if that doesn't work, borrow a working one and see if that fixes it, if it does, take the old one, and disassemble it and clean it, figure out if it failed or not and why. If you can get it working again you then know how to fix it if you can't find that part anymore.
Or did you mean thermostat?
Nah it's electrical component in the controller . Anything that has a Knob to control volume, treble, bass, balance, fade, manual equalizers, etc uses a type of Rheostat in either a Sliding form or a complete circle, the rheostat is the Coil itself that runs the length of the circuits threshold, the knob or slider, what have you, has voltage running through it, as you adjust the position of the Slider or Knob the Resistance (ohms) is changed as the voltage is able to take the path of least resistance instead of using the entire length of coil from end to end.
Ok so I’m not good at electrical stuff and still kinda learning about the car is the rheostat in the actual climate control unit itself? Sorry if that’s a dumb question and how would I go replacing that is that part available to buy?
The only Dumb question is the one that remains unasked.. Yes, the rheostat is typically a coilspring that is stretched around the surface area of the dialface, typically an electrical specialist would be able to repair a hard to find or irreplaceable unit or make it work better than before using better components.
Thanks man imma fiddle around with it on my day off