relay for heated seats? 2003 h6

[mchance1984]

Ive relaced all my fuses, except for my air bag fuses didnt need them going off by mistake. I replaced the bulbs in both heated seat switches located in the center console as per instructions from a previous thread in this forum using radio shack mini bulbs. Im wondering if their is possibly a relay dedicated to the seats. while replacing the fuses under the steeering colume i notcied some relays tucked off to the right, i was wondering if any of them maybe a seat heater relay. the heated seats where non functioning when i purchased the car and are still not working after my simple atempt at repairing them. before i rip them down and replace the element in the seats id like to confirm if their is or isnt a relay for them. seats cosmetically are in great condition. thanks for any input before hand.

[cardoc]

Fuse 21 in the instrument panel fuse box behind the coin holder.

If its good, pull the seat up from the floor and check for battery and ground at the plugs. If both seats are inoperable, its most likely the fuse or a loose wire on the base of the swiches.

[plain OM]

My schematics for 02 and 03 suggest that fuse #4 is also related, as is SBF-2 in the main fuse box (engine area).

The seat heaters also have a relay which powers the heaters and rear accessory power outlet. Perhaps start by checking if the outlet is working (key at ON) -- this will verify if the fuses and relay are good. If they are, the problem is downstream of the relay, which puts it more likely at the seat heater switches, or the seat heater elements.

If there's no power at the rear outlet, then fuse #4, the 20 Amp fuse or the relay could be bad, although I don't recall either of the latter two ever being a problem.

(Schematic attached)

[RedGeminiPA]

Speaking of heated seats, is it normal for the temperature to fluctuate regardless of which position you have the switch set at? Sometimes they get really warm, and other times I have to check to make sure the switch is on. Any thoughts? Is this normal? I've never had a car with heated seats act like this. Could it be a sign of a failing alternator or battery?

[plain OM]

I doubt a failing battery or alternator would show up in the seat heaters but not display other more apparent electrical system failure symptoms.

Does the heater seem to get hot, cool down, but then warm up again? It does appear that the heaters have thermostats to control the temperature, which could cause that to happen. (See attached, which I believe is from the 2003 FSM but would probably be typical for the 2nd generation.)

[mchance1984]

Im still at work, at midnight i'll be done my 36 hour weekend. Tomorrow im off and will try to make time to test the battery and ground at the plug under the chairs. I own a multi meter but am a little uncertain how to test the battery and ground at the plug. I repaired the switches that control the heated seats, they now illuminate when in the Hi and Low positions. Also replaced all the fuses under the hood and behind the coin holder for good measure. I will report back with my findings on testing the bat and ground once I figure out how to do it. thanks for the recomendations cardoc.

plain oem, u said that their is 1 relay that powers the seat heaters and the rear accessory outlet, I own the sedan h6 which I should have mentioned, I do not believe their is a rear accessory power outlet to test in the sedan. where would the relay for the seat heater be located? im tempted to replace it just to know its new and rule it out completly.

[plain OM]

I repaired the switches that control the heated seats, they now illuminate when in the Hi and Low positions.

In that case, don't worry about the fuses and the relay. Looking at the wiring diagram of the seat heater system that I attached earlier, we see that when either the left or right seat heater switch is turned on, the bulb in the switch is powered from the same connection as the heater. For example, on the left side switch, when in the LO position, the power coming from the relay to terminal 5 of connector R43 goes through the switch to terminal 6 (to the heater) of R43, and also to the top end of the bulb. The bottom of the bulb, at terminal 3, goes to ground. This tells us that if the bulb lights up in the LO position, there is power coming from the relay to the switch. The same analysis applies in the HI position. So the relay etc must be okay.

If this is the case, then if the heaters don't warm up, it's far more likely that either the connector to the heater is loose/off, or the heater is faulty (open-circuit.) This will require measurement at the seat heater connector. As cardoc suggested, check for voltage at the harness connector R44, and for loose connections to the switches. In addition, or perhaps before doing those measurements, check the seat heater itself. The seat heater can be checked for continuity (low resistance) between terminal 4 and terminal 1 of the heater connector (e.g. R44 on the left side seat), and between terminal 3 and terminals 4 and 1.

Keep in mind that even in the HI position, the seat might not be warm enough to check with a hand. However, if you sit on it for a while, it should be noticeable.

[RedGeminiPA]

Originally Posted by plain OM

I doubt a failing battery or alternator would show up in the seat heaters but not display other more apparent electrical system failure symptoms.

Does the heater seem to get hot, cool down, but then warm up again? It does appear that the heaters have thermostats to control the temperature, which could cause that to happen. (See attached, which I believe is from the 2003 FSM but would probably be typical for the 2nd generation.)

Yes. Both seats do it. They get hot, cool down for a bit, then get hot again. It's far from being a steady amount of heat at all times. Is this normal, or could the thermostats be going bad?

[plain OM]

Originally Posted by RedGeminiPA

Yes. Both seats do it. They get hot, cool down for a bit, then get hot again. It's far from being a steady amount of heat at all times. Is this normal, or could the thermostats be going bad?

It sort of sounds as if the thermostats are switching. I have the seat heaters on my 07, but so rarely use them, and when I do, for so short a time, that I can't say I've noticed how constant the heat is.

Perhaps others here with same model year 2001, or Outback generation (2nd), can comment on the way theirs' performs.

[cougar70]

My wife's 07 OBW has the heated seats and the seats will heat up, switch off, cool down a little and switch back on and continue to cycle like that, otherwise if just turned on the elements would end up overheating the seats.