850 heated seat not working

[Ozark Lee]

If memory serves, the notice indicated that the thermo could fail and cause the heating element to burn out and in some severe cases, cause the foam to catch on fire.

I never saw the recall but I can see that it might be a true story.

DSC01979.JPG (213.61 KiB) Viewed 11241 times

That was what one of my burned out elements looked like. Sadly the used replacement I bought only lasted about one "season" before it burned out again. Replacement pads only cost around $50.00 USD. Changing them is tedious but not difficult.

...Lee

[wildlifeguy]

The seat heated for only a couple of days after I found the broken wire.
I'll have to venture into removing the seat cover to get to the heat element. I found a heat pad at an automotive electronics store for $15.00 new. might give it a try.
I just HAVE TO FIX it!:)

[bobbych]

has anyone changed the lower heater pad on these yet? is it hard, is there a guide?

[wildlifeguy]

it is as described in previous posts. the hog rings are the biggest issue, but once you get past that stage of the game, you should be good. the heat pad is surprisingly easy to remove as mine was simply placed between foam and leather.

m

[dwd]

Neither of my front seat heaters are working - though they both worked just fine last winter. The heater switch lights come on but the seats don't warm up.

I followed Ozark Lee's very helpful diagnostic steps above. First step: there is power getting to the seat when the switch is turned on. So far so good. Then I got to this point...

Backprobe the red wire on the black connector and check it for battery voltage as well, the black wires on the power connector are a good ground point for the meter.

If you have good voltage there it means that the thermostat and its circuit are good. If you don't have voltage there it means that the thermostat is bad (not likely) or the wiring to the thermostat has come unplugged (more likely).

When I got to this step, I did see battery voltage on the red wire - but only for about the first 20-30 seconds after switching on the heater switch. Then it would drop to zero. If I then switch off the seat-heat switch and wait a while, then turn it back on, the same thing happens - voltage at that red wire jumps to ~12v and stays there for 20-30 seconds, then drops to zero.

This to me implies that all the connections are good but that the thermostat is tripping off very quickly - perhaps at too low of a temperature or something? Does anybody have any other ideas or any suggestions on what else I could check?

The odd thing (to me) is that this happened on both seats at the same time...

Thanks,
- David

[turbozutek]

If there's a short circuit in the heating pad, the thermostat itself heats up very quickly and trips out. I'd measure the resistance of the heating elements and check if they are shorted.

Chris...

[rspi]

Assuming that the voltage is good on the red wire next move to the yellow wire. On a normally working system you should read voltage there but it will be less than full battery voltage. If you read full battery voltage on the Yellow wire then the seatback heater element has burned out...Lee

Which yellow wire are you talking about? The one at the black connector or grey connector?

Also, when removing the seats to the 850, does one have to disconnect the battery to avoid the SRS light if the seat has the side air bags?

[rspi]

Yea, I did it.

The yellow on the black and grey gave the same results so that didn't matter.

I got the passenger side working. I was able to get the thermostat out of the seat without removing the seat. It wasn't plugged all the way in. The drivers side has no power to the yellow so I guess the lower pad it bad. I'll take it apart and see what's up.

[petax]

850 T5R - my drivers seat suddenly got hot and remained heated, and it was not even switched on!!
It is mid summer and I got out of the car sweating like the proverbial pig. Is this a known issue?
I would start a new thread, but it seems to make more sense to tag on to this one as it has all the diagnostic information already.
Thanks in advance.