Is it cold enough there to need them? Maybe there is a factory setting that does not allow them to turn on unless it is a certain temperature outside? The Users Guide does give this warning, which is because their have been lawsuits filed due to paraplegics getting burned by seats that got too hot:
• Persons who are unable to feel pain to the skin because of advanced age, chronic
illness, diabetes, spinal cord injury, medication, alcohol use, exhaustion or other
physical conditions must exercise care when using the seat heater. It may cause
burns even at low temperatures, especially if used for long periods of time.
• Do not place anything on the seat that insulates against heat, such as a blanket or
cushion. This may cause the seat heater to overheat. Sitting in a seat that has been
overheated could cause serious burns due to the increased surface temperature of
the seat.
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I'll try mine in a few minutes when I leave for work. It's 70 here, and I'll see if they turn on.
They should work no matter what. If its not a fuse then it could be a whole block out. Like a specific distribution block. You would have other problems if that were the case though.
They work at all temps, I've turned then on for the passenger when it was in the 90s. Haha
But my passenger sat and didn't buckle up for a while. The passenger one would keep turning off after a few seconds, so maybe that has something to do with it?