Heated Seats Mystery

I have heated seats in my 1996 2.5 20v 850 CD Estate - front and back but none of them work. I checked out the wiring under the front seats and found that they had been disconnected from the thermostat. I pulled out the thermostats and one connector terminal was broken off each of them, so I soldered them back on and replaced the wires. Still no heat.... I've checked the themostats for continuity - fine and I've tried bypassing the thermostats - briefly by shorting them out (by connecting the 2 wires together). Still no heat... According to Volvo my car has had the heated seat modification, so why no heat? Fuses are ok, switches light up. Oddly, the rear seats don't heat up either. Should I go back to the dealer for a diagnosis - I'm sure it can't be pad failure on all 4 seats - or could it? Jeremy

Check for continuity across the heater pads. They go open circuit at stress points.

i would replace one of the thermostat pads and check this individually on all of the seats, it may be possable that when you repaired each spade you damaged the pad with the heat of your iron... at least this way you can be sure..... cheers jod

Have you got a + feed at the stats?

I would check all the seats for about 200 - 400 ohms at the heating elements and check for 12VDC at each seat as well PS, heated seats in the rear, never seen that before.

Heated seats feed 

rear seats 

There are only 2 wires on the stat, one will have the feed the other goes to the element, try both to earth, obviously have the switch on the console switched on! Another point has occured to me, you say the car has had the recall on seat heaters? if so the mod involves tidying up the wires underneath so they arn't easily disturbed or kicked off by size 12s in the back, just a thought

If you car has had the recall then the stat in the base foam should have been removed/by-pased and a control box fitted under the front edge of the seats to control the seat temps. If the thermostat in the base foam is still there and connected then your car has not had the recall carried out!

Thanks to everyone for their help I'll check out the wiring again at the weekend, I'll also call Volvo and find out what was done on the recall. I'll post let you know what I find out! Jeremy