MV seat heater...

[DenverB]

So I'm driving right now and realize my butt is still cold. I haven't messed with these at all, is there a common failure point in them? Possibly just a fuse?
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'77 Transporter/camper (Bussy - Reef Blue/Pastel White)
'67 bug (Santos - VW Blue)
'84 Vanagon Westfalia (Pink Flamingo - Pastel White/Pink)
'88 Vanagon GL Westfalia (Frankie Says - Wolfram Gray)
'02 Eurovan Weekender (Green Apple)
'95-'03 Eurovan full campers and weekenders (rental fleet)
'84 -'91 Vanagon full campers and weekenders (rental fleet)
'72 Porsche 914 (Greta - RIP)

www.RockyMountainCampervans.com

[Abscate]

Start by looking at 12 VDC at the connector of course.

SB 11 Fuse 11 is the source on my MY2002

I can send the full troubleshooting flowchart - PM me.
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.ssS!

[jjvincent]

Don't be surprised if these seat heaters start to stop working (the drivers butt goes first). Over all of my years working with heated seats most of the time a few wires break on the pad and the whole thing goes out. It usually starts after 10-15 years of use. If your back is warm, then you have 12V then.

I don't know if VW sells a pad for these but I know Audi did years ago but even in the 90's, they were $300/pad and many just decided to forgo it.

[Zeitgeist 13]

My seat heaters appear to heat too well. Even at the #1 setting, the driver seat initially gets uncomfortably hot and then settles down. The passenger seat does the same thing, but the seatback matrix seems to have a short and has burned a scorched spot into the fabric
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[markcm2]

[DenverB]

Well… It seems that it is a short in the actual heater itself. I just turned on the passenger seat and drove about a mile before starting to smell the burning of plastic. Looked over and there's a scorch mark on the back rest of my passenger seat. I think disabling them altogether is probably my wisest move at this point
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'77 Transporter/camper (Bussy - Reef Blue/Pastel White)
'67 bug (Santos - VW Blue)
'84 Vanagon Westfalia (Pink Flamingo - Pastel White/Pink)
'88 Vanagon GL Westfalia (Frankie Says - Wolfram Gray)
'02 Eurovan Weekender (Green Apple)
'95-'03 Eurovan full campers and weekenders (rental fleet)
'84 -'91 Vanagon full campers and weekenders (rental fleet)
'72 Porsche 914 (Greta - RIP)

www.RockyMountainCampervans.com

[markcm2]

[Zeitgeist 13]

Thanks for the insights. I've been meaning to post up some questions about the heaters for a while now.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Xtremjeepn]

These failures are exactly why I sought out aftermarket seat heating kits for the vans I build. I've even replaced good seat heaters to avoid having a failure shortly after reupholstering a seat.

Unfortunately the factory heaters aren't available any more. Which also means having to swap out the switches.

I've found ones with factory looking switches but they don't fit the holes perfectly and require a tiny amount of fab work to get a factory look.

These are aftermarket switches to go with the aftermarket seat heaters. They light up and work just like the factory ones.

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http://www.cavevan.com

[Zeitgeist 13]

Has anyone ever measured the resistance values of the stock functioning heater matrix? I'm trying to figure out why folks have been going to the trouble of wiring up aftermarket switches, vs just using the factory setup with the new matrix. I have an inexpensive seat heater kit coming in a couple days, but both my seats have shorts in the matrices, so measurements aren't an option.

I'll bypass the factory setup if I have to, but it seems kinda redundant to run a new harness.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Abscate]

That middle button will tell you there is a 30% chance it is already raining.
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.ssS!

[Zeitgeist 13]

Press any button and the ghost of Carnac the Magnificent will appear
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Zeitgeist 13]

My kit arrived today, so I tore into the passenger seat, and...holey moley! I'm surprised I didn't burn the van to the ground. The matrix completely pulled away from the fabric and collapsed onto itself. This explains why it burned a hole in the seatback, and my son's jacket.

The base wasn't much better

If your seat bases have pokey bits busting through the fabric, this is probably the culprit.

This is the new matrix, which appears to be decent quality, as is the rest of the kit

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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[markcm2]

Casey,

Please fill us in on how this ends up. Details would be awesome, like if you have to replace the switches/controls and any tips tricks for removing and installing the seat covers.

Thanks

[Zeitgeist 13]

Hi there, I have a couple pics in my "Darkside" thread https://www.thesamba.com/vw/forum/viewtopic.php?p=9280440#9280440.

Here are my stream of consciousness thoughts:
Essentially, be prepared to remove both pedestals and find a way to pry up the carpet (it's kinda glued down). I'm sure there's a way to use the factory wiring harness, but I was time limited, and the kit seems to be really high quality, so I went with what they sent. The heating pads are made to be trimmed, so you can use scissors to shorten the lower seat cushion sections. Be careful to be sure the heater wires emerge from the seat bottom in a place you can access for installation and removal...and that they don't run afoul of anything when being slid fore/aft. The seat cover retaining rods are maddeningly fiddly and confusing to remove/install, so definitely only disassemble one seat at a time so you can use the other as a reference.

I'm very pleased with the performance of these heaters, and for the price the results are amazing.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[VanGeek]

Refreshing this thread... I've purchased the aftermarket kit that Casey and others have used. Still debating if I will adapt the OEM wiring or use the controller that comes with the kit: https://www.ebay.com/itm/263949756610

I temporarily wired the aftermarket controller into two of the seat heaters and placed them on the outside back and bottom of the seats. They warmed-up, but on level-5 didn't seem to get especially hot. Seemed less warm than the maximum setting on my other vehicles with OEM seat heaters.

I may try wiring the carbon element pads into the original wiring. That requires cutting-out the thermistor from the original VW OEM seat-bottom warmer and adding it to the new carbon heater pads and re-wiring the connectors so they are in parallel. This is because (a) the OEM controller requires the thermistor connection and (b) the OEM harness has the bottom and back pads wired in series. Each is 5 ohms for a total of 10 ohms. But the new pads each have 10 ohm resistance.

For those of you with aftermarket seat heaters, please reply with your feedback on if you used the aftermarket or OEM harness, and if the ebay/amazon carbon heaters felt warm enough to you or not.

[VanGeek]

(5/7/24 -- updated with add'l harness deconstruction pics)

OK -- didn't get any feedback here so I proceeded with my own evaluation.

As mentioned previously, I temporarily wired the aftermarket controller and tested the warmers. Subjective feel was definitely warm but not as hot as my very-hot Ford OEM warmers (although the Ford warmers are the hottest I've ever had on any vehicle I've owned).

I started to plan the wiring and routing for the aftermarket controller. Was reluctant to use the OEM wiring since it required modifying the harness and making assumptions about resistance, power, and thermistor functionality. OTOH the OEM warmers aren't available, so the OEM harness has no future value. I modified the harness to put the bottom and back warmers in parallel and to incorporate the OEM thermistor. Connected everything up and the warmers seemed to work just fine with the OEM switches, fuses, relays and a modified harness. Subjective feel of heaters suggested heat output was the same as with the aftermarket controller.

Based on this, it's WAY easier to modify the harness vs install the aftermarket controller, switches, wiring, etc. And you get to keep the original seat warmer controls in the dash. Incorporating the OEM seat bottom thermistor is necessary and seems "wonky" -- but it's only there to keep the OEM control logic happy. In addition, the aftermarket warmers are designed with their own thermistors that restrict power locally -- they don't provide feedback to the aftermarket controller and there is only +12v and ground connected to each warmer. So I don't see any risk or danger of malfunction here.

Here are some WIP photos.

Seat heater had stopped working. Here's why... One of the wires broke in the heater. The bottom and back heaters are wired-in series so one break kills everything

Back of the bottom seat heater. You need this harness and the thermistor to make this work with the OEM wiring and switches:

The harness removed from the lower seat heater. Conduit/sleeving removed to access wires for modification. Thermistor left intact. Heater wires cut-out from fabirc/glue and exposed and thermistor/wiring/glue left intact.

Pic of the modified harness. Black/yellow wire is +V and Brown wire is ground. Original serial harness ran +12V into the back, with output of the back into +V of the bottom, and output of the bottom to ground. Harness is modified to run separate +V and ground to each heater. The thermistor visible in upper-right.

Here is the harness with both heaters connected

Here is the harness all wrapped-up and ready to install. Thermistor was carefully protected with an extra layer of tesa tape and gently wrapped around the harness and then wrapped with tape. You can't see it well any longer in this pic. I'll update the thread after my cushions and covers are clean and dry and ready for reinstallation

[VanGeek]

The seat covers had a gummy, sticky finish on the inside portions facing the seat heaters. I wanted to clean them before reassembling with the new heaters. A samba member recommended using citrasolv for removing the sticky parts.

I wondered why the seat heater areas were sticky. I initially thought that VW may have used an adhesive between the heaters and covers but that really doesn't make sense.

I acquired a product that is different, although similar to citrasolv. It has plant-based cleaners and mild solvents and is safe to use on most surfaces. I initially tried spraying the cleaner and wiping the seats, but this made a mess as the gummy areas fell off around my sink and onto other areas of the seat fabric. So I sprayed the inside areas, let it soak for a few mins and then saturated with warm water in the bathtub. This removed the gummy finish, and A LOT of additional decomposed foam by-products.

It seems VW used a very thin foam sandwiched between the outer and inner fabric layers of the seats. This foam seems to have properties similar to the foam VW used in the blender box and around some of the wiring harnesses. That's right, it has a unique ability to decompose into a sticky gummy mess after ~20 years of use. The areas touching the seat heaters are especially decomposed -- hence the build-up of sticky gummy crud that likely traveled from inbetween the fabric layers into the inside layer touching the heaters. At least that's my theory....

WHY WHY WHY could VW not select a durable foam on these vehicles??? I've worked on older US, Japanese, and European vehicles where the foam was dry but had not become a gummy mess....

Anyhow, I saturated the seats with the cleaner, massaged it into each seat cover, and then rinsed with warm water in the tub. Performed the cleaning + rinse three times. Performed two more rinses to ensure all the cleaner was extracted from the fabric. A LOT of broken-down foam liberated from these covers. Glad they're clean and the foam bits are gone. However, the foam added ~1/32" of thickness to the fabric although it was mostly crushed or broken down so I'll learn more if this affects the fit of the covers after I attempt to reinstall them.

Here is the inside of the passenger bottom cushion cover. The dark area in the middle is the sticky, gummy part.

Here is the inside of the passenger back cushion cover after removing the gummy part, cleaning it, and flushing out the tiny bits of foam. You can still barely see the stain left behind from the wires in the heater that were behind it but it's otherwise clean and stain free:

Here is a view of the decomposed foam poking out between fabric layers in a seam. This is prior to cleaning:

Here is the bottom seat cushion during the second rinse. The water is dark gray and filled with very tiny pieces of foam that were flushed out (and perhaps a little dirt?). On the third clean and rinse, there was very little foam in the water. Almost none. Can't wash and flush it forever and called it a day:

[VanGeek]

You see a random late-model Eurovan seat cushion. But I see that a factory seat cover with decrepit foam removed and fabric cleaned fits nearly perfectly on the aftermarket ebay seat heater and OMAC seat bottom cushion. Very pleased with the fit of everything. In the second photo, you can barely see the bump from the aftermarket seat heater. Quite frankly, the new setup has less bumps and irregularities than the old heater and cushion so I'm satisfied.

[VanGeek]

This project is now finished. Like most things, it's a lot easier when you know how. The second seat was disassembled, cleaned, reassembled with new heaters and seat cushion with modified harness in less than a few hours. The second cushion from OMAC also fit perfectly, although was slightly different in finish and had a hole for the seat heater (the first one didn't). Me thinks OMAC has multiple suppliers and this may explain why some forum members received under-sized cushions while others (like me) found them to fit perfectly.

If your seat heaters are shot, this is a good way to replace them with a solution that still uses the original wiring, fuses, and switches.