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Re: Yet another heated seat question... Posted by Ari [Email] ![]() ![]() In Reply to: Yet another heated seat question..., Micah in NC, Wed, 28 Nov 2001 17:05:28 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Yes, you do need a seat heater controller to make things work. In your '84, only two wires go to the seat - power that is there when the key is ON, and ground. There is a thermoswitch in the seat itself in series with the power and the heater. When the seat drops below a certain temp, the switch closes and the heater comes on. When the seat get hot enough, the switch opens until it cools down again.
The newer controller really isn't a rheostat - it's a controller. You have three wires now - ground, a temperature sensor, and the other side of the heater coil. The heater coil and sensor go into the controller in the dash - the little gizmo with the wheel to set the temp.
The controller measures the temperature of the seat with the temperature sensor. If the seat is colder than the setting on the dial, a relay inside the controller closes and applies 12 volts to the heater coil. When the seat warms up enough, the controller opens the relay. For hotter seats (higher number), the relay stays closed longer.
If you just hooked up your new seat to your existing wiring, the seat heater would be on HI all the time, and you'd cook your buns.
The good news is that the controller is the same for both 900 and 9000 - all the 9000's have seat controllers, and the 900 after around '88. So find yourself a junkyard and have at it.
Good luck!
posted by 12.79.5...
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