How hot do heated seats get?

sounds like there is 12 volt power to the switch, but power is interrupted to the heater pad-element, or the pad-element is bad or broken. Check to see if there is power after the switch and to the pad, in other words, you need a tester of some kind, a voltmeter, ohmeter, or one of those that light up a bulb to check continuity. A visual check of all the wiring and connections is the first step, if all seems ok, then do a continuity test. If there was a blown fuse between the switch and the power source, the switch light would not come on. If there is a fuse between the heater pad and the switch, I don't know, you need to get model-specific information from the Service Manual or maybe the Owner's Manual where it lists the fuses and the circuits they protect.

I'm also thinking it's way too early for a 1999 to have this problem, particularly one that came out of Clearwater, Florida (not a lot of winter down there), and one with so few miles.

When you turn the heat on, the switch lights up. But is there a fuse somewhere that could be bad, letting the dash switch light up but not letting the seats heat?

Jess

1963 XKE (sold)
1976 XJ12L (dead)
1988 XJS (sold)
1999 XJ8

my car is an '84 XJ-6 with aftermarket seat heaters; they get hot enough with the switch in High to annoy me after 20 minutes, even in 20 degree outside temperature, but after 20 minutes, the heated air is hot enough anyway, so I just turn them off. Just in case I was to become unconscious with the switch on High, there is a thermostatic sensor which will turn the seat heater to off after 35 minutes, by which time I suppose that I would be burning. A new version of my heaters has a vibrating-massaging action as well as two and three heat settings, and a lighted switch. I have no experience with the 'factory' seat heaters, although they most likely came from an aftermarket supplier anyway, European or North American. I think the elements in your heaters are deteriorating from use. Might be time to get new heater kits at around $250.00 per seat kit, but your car being a 1999 model, seems too soon. Mine are over 9 years old and still burning. If you have factory heaters in the rear seat, you could try to move the rear seat elements to the front seats, assuming the Heater Pads are the same size. It will take some exploring by removing the seat covers. You might only need the seat pads, not the Lumbar pads. Here's a picture of the finished job, showing the temperature sensor and wiring under my car seats.

my car is an '84 XJ-6 with aftermarket seat heaters; they get hot enough with the switch in High to annoy me after 20 minutes, even in 20 degree outside temperature, but after 20 minutes, the heated air is hot enough anyway, so I just turn them off. Just in case I was to become unconscious with the switch on High, there is a thermostatic sensor which will turn the seat heater to off after 35 minutes, by which time I suppose that I would be burning. A new version of my heaters has a vibrating-massaging action as well as two and three heat settings, and a lighted switch. I have no experience with the 'factory' seat heaters, although they most likely came from an aftermarket supplier anyway, European or North American. I think the elements in your heaters are deteriorating from use. Might be time to get new heater kits at around $250.00 per seat kit, but your car being a 1999 model, seems too soon. Mine are over 9 years old and still burning. If you have factory heaters in the rear seat, you could try to move the rear seat elements to the front seats, assuming the Heater Pads are the same size. It will take some exploring by removing the seat covers. You might only need the seat pads, not the Lumbar pads. Here's a picture of the finished job, showing the temperature sensor and wiring under my car seats.