When I bought my car one year ago my '87 The passenger side heated seats were not working, my driver side was working up untill one month ago. I tested the passenger side and this is what i got.

The lights on the switch both light up
12Volts of current at the connection from switch under the seat
2.4 Ohms of resistance at the connection from seat.
all connections under seats appear to be hooked up

What could be wrong?

Neither the bottom or back heat up on both the driver and passenger.

If I'm not mistaken there is a thermostat in line with the heater grid that turns off the heater grid when the seat reaches a nice temp. It keeps the heater temp at a nice 80-87F. When this thermostat breaks (which it does) you have a non-working seat heater. I'm sure you can find one at the dealer or be lucky and find some at the yards but as for me I just take the thermostat out, place a wire where the thermostat was, and turn off the seat heater when I'm warm enough. Just make sure you don't forget to turn off the switch once it warms up or it will really warm up your bottom. Good Luck!

Sincerely,

Nickvjr
1979 264GL 120,600