WTB: switches and relays to control seat heaters.(I posted in parts section already) - I recently bought a pair of front seats from a 98 BMW 750iL, full power and heat. I do not have the switches and stuff to control the heat. I want to buy some switches/relays etc to make the heat work. I have an 82 300SD, so something that looks like those switches would be a plus. Also, the BMW seats have a temp sensor inside that measures temp and controls heat along with a potentiometer that the seat occupant can adjust. Anything that works like that would be a plus too. What I really need is ideas here, even crazy ones. So please, fire away! thanks!

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Set the seats on fire. Caveat - good for one use only.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

L.L.Bean or Cabela's carry socks which are heated by 9 volt batteries....
Check to see if they have boxer shorts with the heating elements in them.

for instance:
http://www.preparedness.com/allweatclot.html

http://www.nextag.com/serv/main/buyer/OutPDir.jsp?search=heated+mattress+pad

It sounds like if you want the whole potentiometer setup and all for controlled temp (which you very well may end up needing regardless to get things working) I would recommend using the switches/setup from the BMW and putting it somewhwere in your automobile.
BMW isn't that far from Benz...atleast the parts sometimes fit in the same spots

http://www.heaterseats.com/

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Eat lots of beans!

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

Way to pull the battery down....I can see that alternator going up in smoke now...Do these seats bolt in or is this going to be a bailing wire/duct tape affair.....

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

But that will make the paint peel off.................

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Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Just remember not to get your posterior burnt on this one. As you truly may have to sit on the blisters. But on the otherhand the aftermath could make a very interesting thread.

These seats WILL bolt in with whatever heavy duty adapter blocks I need to construct. The duct tape is on the original seats I have now. I'd like to be driving this car for the next 10 years, the last 9 have been really good but the seats and my back ain't what they used to be. Other guys have really nice seats in their cars, why not me? Besides, this has to be a lot less work than building a house or rebuilding an engine.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

I guess as long as they aren't made of wood and held in with lag bolts...I wonder, hypothetically of course, if a homemade seat mount failed during an unfortunate incident if there could be legal ramifications?? Might want to keep some waivers in the glovebox....

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

You mention the seats have a sensor/thermistor. This may be in a control circuit on the bmw that fundementally just opens and closes a relay. Same on all cars with heated seats today I would expect. The pots just change the pad load on the thermistor for varience of the shut on/off point temperature or perhaps the bias on a transistor in the main controller.(more likely) This thermistor or sensor is going to be a different value from one car brand to another as there would be little standardization of this part I would expect. Conversly any other control brand from any maker should be ok as long as you incorporate their sensor in your new seat. I guess I would just get some other brand control boxes and the seat sensors out of the same car as the easiest overall solution. The same as you are trying to do. Believe the majority of vw have heated seats in last few years and perhaps a good donar source. Their finger controls are reasonably small and neat. Since you are looking for suggestions.Why not just use the controls already installed on bmw seats. Beats trying to find a new place and they are already there. At worst probably only have to get replacement pots from an electronics store to match electrical resistance value of donar part. If you are lucky the bmw pots may be close enough when checked with ohmeter. Only should be 1/2-1 watt potentiometers so not expensive in fact may be able to pull pots from donar controls if required, even cheaper. Think the seat heat switching units were down around fusepanel on vw. Suspect also the actual resistance of the seat heating elements from brand to brand will not have a compatability problem at all. Just some more thoughts. But remember it's your butt that burns.

Thanks for the ideas guys. I would have loved to get the OEM switches for the memory and heat with the seats, but that was not to be. I bought them from a nice guy on E-bay who had removed them from his own car so he could put in sport seats. Buying the controls from BMW would probably cost me more than the seats but maybe I should start checking the junkyards. Still trying to understand the wiring. Fortunately, all the position switches are on the seats themselves. Barry, good thought on VW as a possible source. Also, I remember that the seats in the 75-78 Saabs I used to have had no operator switches at all. They had a contactor that made when you sat in the seat and broke when it got warm. Maybe Saab continued this with leather seats, I don't know.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

bump - still looking for ideas. Barry, I've found a few VW and Audi switches on ebay which have a wheel. I wonder if this works like the ones do on the 750iL. There, the current goes to the seat until the thermistor/temp sensor changes resistance, and then feeds back to the seat switch. I found some wiring info on a BMW site, does anyone here know a similar site for VW where I could find schematic info on the seat heating?

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

The following threads may help you find a heated seat solution:

Thread number:
77352 (this one from Jeff, BoostnBenz)
78496 (seat rebuild including heated seats, Eric Starr, Peyton300TD)

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)