Are 1970's Gm Power Window Switches Polarity Reversing Switches？

Yes, power window switches in vehicles from the 1970s, including those made by General Motors (GM), are typically polarity-reversing switches. This design is fundamental to how power windows operate, and it was already in use by that time.

Understanding Polarity Reversing Switches

1. Basic Principle: These switches work by reversing the polarity of the voltage sent to the power window motor. The direction of the motor's rotation—and consequently, whether the window moves up or down—depends on this polarity.

2. How They Work:

   • When you press the switch one way (say, to roll the window up), the switch connects the motor in one polarity configuration, causing the motor to rotate in a direction that raises the window.
   • When you press the switch the other way (to roll the window down), the polarity is reversed, and the motor spins in the opposite direction, lowering the window.

3. Design in the 1970s:

   • Vehicles from the 1970s, including GM models, used this type of system for their power windows. The technology was relatively straightforward and robust, making it a popular choice for power window controls.

4. Relays and Wiring:

   • In some designs, especially in older models like those from the 1970s, the reversing function might be achieved through a combination of the switch and relays. The wiring and relay arrangement would handle the actual polarity reversal.

Considerations for Classic Cars

• Replacement Parts: If you are restoring a vehicle from the 1970s and need to replace power window switches or components, it's crucial to get parts that match the original specifications. Aftermarket parts may have different configurations.
• Wiring and Connections: Due to the age of these vehicles, wiring and connections may have deteriorated. It's essential to inspect and, if necessary, restore these components to ensure safe and proper function.

In conclusion, power window switches in 1970s GM vehicles are indeed polarity-reversing switches. This is a standard design for power window systems, allowing the windows to be raised or lowered by changing the direction of the motor's rotation.