robbz23

Sometime over the summer my seat warmer gave up and quit working. Well with the temps around 0 F here in Sweden now I decided to take the seat out and look at it. Yes my car is a normal NA 04. My problem was on the drivers side, but it might also apply and help for the passenger side too.

I would first suggest looking at your switches. If you aren't seeing the light come on when the switch is on, then you aren't getting power to the switch. From what I can tell full power runs from the Seat Heater relay and fuse in the engine bay to the switch and then to the seat heaters.

I have attached some pics from the service manual for the overall system and the switches.

robbz23

Ok so if that isn't the problem then you will need to take the seat out of the car. Once the seat is out flip it up so you can look at the bottom. In the picture you can see I have detailed the connectors for the seat warmer.

Undo the Main Connector and check for continuity. If it is room temp or below the thermostat will be closed and you should find continuity between the two contacts. You can see an illustration of this in the pic thermostat test.

If the Main connector has a short then undo the upper section connector and check that one to determine whether the problem is in the bottom or upper section. In my case the main was shorted but the upper section was fine which means the problem was in the lower section.

NOTE -- If both connectors are disconnected there will be no continuity through the two contacts on Main. See my wonderful diagram of the circuit.

robbz23

So now I know the problem was in the bottom section I needed to remove the seat cushion. I recommend wearing gloves so you don't cut yourself on the seat pan which has some sharp edges. I didn't take my own advice and now have a large cut on my hand.

Undo the two pieces on for the sides and the one for the back, and then pull the front edge out of the groove. Make sure you notice how the front edge is stuck in there as it is a bit confusing when putting it back.

robbz23

With the cushion removed I removed the rings from the seam that runs across the back of the cushion. I could immediately tell what the problem was because one of the two wires was cut and the other one was nicked. I think this was because they were being pinched between the plastic in the cover and the metal bar in the cushion. I added a short section of new wire in because it didn't look like I could stretch it and fix it, and I covered that with some heat shrink tubing and liberal wrap of electrical tape.

robbz23

Now this was the solution to my problem however you might find that it could be something else. Like the thermostat or a break in the warmer wires. This guy has written a good article covering some of these issues for his Passat.

http://passatb5.wikidot.com/heated-seat-repair

The little lump there is a thermostat to keep the warmer from getting too hot. Once the temp goes over 99F it will break the connection. You should also visually inspect the lines in the warmer to see if it is broken somewhere. Just like the rear defroster there can't be a break anywhere in the wire or the whole circuit won't work. Hope this helps you guys.

merkidemis

I am working on fixing mine at this very moment!

Pro tip: When removing the seat, leave the power connected so you can slide the seat back and forth for easier access to the bolts attaching it to the car.

Then, once it's free, disconnect the negative battery connection, and let sit for at least a minute, then disconnect the wires. As per the maintenance guide, this allows the airbag's backup power to drain. No exploding airbags in the apartment, thank you!

Also, after hauling that sucker up 3 flights of stairs, I am considering some lightweight Recaros.

Mazurfer

This is the best advice in the whole thread...........don't ask me how I know. If you don't....there will most likely be massive blood letting!

mscamp02

iTrader: (3)

I absolutely love you for this diy thread...great write up, now the weather just needs to get better so I can try this.

merkidemis

On the pad, the thick wires coming from the connector are soldered to tiny, thin wires on the pad. On mine, that connection broke. Soldered on an extension, very carefully, added some hot glue and gaffers tape to hold it in place. Reassembling to test!

Also, as a complaint, these pads are really, really tiny. I may put in an aftermarket pad this spring. For now, I just want this one working.

merkidemis

Victory! I have heat! And, as a bonus, the previous owner had left 5 pesos stuck in the seat.

As before, the connection of the thick power wire to the thin pad wire itself was broken. If yours breaks, there is another inch or so of the thin pad wire you can work with, but you have to free it first.

To get at it, you need to use a knive, like an Exato or utility razor, to gently cut/scrape away the patch covering the wire. The wire runs across the seat side to side (not front to back). Start from where the thick power wire entered the pad, and gently cut until you find the thin pad wire. It will be bare, so look for metal. Also, be careful you are only removing the patch part of the pad fabric: don't cut all the way through. There is a fair amount of fabric and glue here, but go slow and carefully.

Once you've found the start of the wire, you can continue exposing it until you have enough to work with. I then soldered on a peice of wire that was thicker then the pad's, but thinner then the power lead. This gave me a little more wiggle room and will put less stress on the pad wire.

Once attached, cover and secure with hot glue, then cover with some electrical, duct, or gaffers tape. Gaffers tape would be best, as its more like a fabric version of duct tape.

Also, another tip, the wire rings that hold the leather to the seat cusion can be cut, replaced with heavy duty zip ties to secure the upholstery. Rotate the latch part down so you don't poke your ***. They should last a good long while.

robbz23

Great tip about the airbag. I was worried about it so I didn't want to test continuity on any line that I didn't know where it went because I wasn't sure which one went to the airbag. I also had about 0F outside taking my seat out and had to carry it up 3 flights. Lets just say I was happy to be back in the apt.

Yeah I got mine pushing the cushion back onto the seat pan. I was trying to get it to squeeze through the backside where the top meets and caught my thumb on a hole in the seat pan. It took a while for the blood to stop.

Mazurfer

I was actually installing lights and wiring for the back seat foot area. I was running the wires across the bottom of the seat pan and feeding them in and out of those circular holes with my finger and......well.....you can guess the rest. My god that's sharp!

robbz23

@merkidemis - Glad to hear you got yours working. Sounds like you had more trouble then I did. Thats a great tip about the rings being substituted for zip ties. I struggled with those things for a while.

2kwik4u

Awesome write up! Our "new to us" '05 has a drivers seat that doesn't warm. I'll be digging into it one night this week. I'll be sure to let everyone know how it goes.

greenarixate77

Hello all - I would like to ask for some advice on this issue. I have the same problem but it is a bit different.

I pulled out the seat then disconnected the main connector for continuity check from the two pins - no connection

I plugged back the main connector then unplugged the upper connector to check - no connection either

I unplugged both connectors and ran the following for continuity:

Main connector's power to upper connectors power - 1.2 short

Main connector's ground to upper connector's ground - 0.2 good connnection


Does this mean that the heater itself is non-operable? What should be my next step? Thanks in advance.

greenarixate77

BTW, I removed the seat cushion and the wires do not seem to be broken and I cannot find any bare metal from the wires

elysium19

iTrader: (1)

1) Great write-up...so if more than one person had the wires severed at that same spot, thats very helpful. Means we have a place to start looking...I have the same issue.

2) A related tip if you are "checking connectivity" and the seat motor stops working. I had this problem and resolution:
https://www.rx8club.com/series-i-trouble-shooting-95/help-electric-seat-frozen-forward-188388/

tibyABv6

i guess i am not the only one .... my driver seat lower sections does not work also ...
I am hoping that it is just ripped wire ... easy fix. Will look in to it when car comes out from storage in April.

dodgingwrenches

Hi there. Would the lower and upper heaters work separately? I have power to the switch (light goes on) but the entire seat won't heat - neither backrest or seat bottom.

Mazurfer

Your answer is in the second post, but start with the first one and read thru it, then the 2nd one.

dodgingwrenches

I did read the entire thread, thanks. The OP had a different problem since one of his worked and the other didn't. Both of mine don't work so instead of assuming they are both somehow toast, can something else be keeping them from working?

TheWulf

iTrader: (4)

Electrical problems suck... gotta start at one end with a multi-meter and work your way to the other*. Post 2 does pretty much show where to check though.

If you're desperate/brave you can ponder showing up at M&M tonight and I'll bring the multimeter

dodgingwrenches

Multimeter? Stop speaking Chinese with me, Marc. I don't understand it! hehe

Yeah, saw this too late, sorry. But let me know if I can harass you another time with your multimeter or other *insert electrical term I don't know* to *insert electrical related verb I don't know*. Can you tell I'm clueless with anything electrical? Somebody spell it out in plain English please

robbz23

to answer you question. No one part would not work with out the other. It is one big loop through the bottom pad and then the top pad. However with a multimeter you can check to see where the break is and diagnose from there...

dodgingwrenches

Okay, thanks robbz! I was hoping they'd work independently, meaning my failure was due to something as simple as the switch