2000 deville rear heated seats.. Need wiring help with custom project :)

[madmikeee]

OK So my 2000 Caddy Deville is going to be headed to that great Cadillac road in the sky soon. I decided to rip the back seat out and turn it into a man couch for my basement. I might as well keep at least a little of it for posterity right?

I fully intend on trying to get the heated seat elements to work . My need is this. Has anyone done this themselves? If so could you offer a tutorial on how you got the heating elements to function? If not, can someone offer some advice on how to do so? The wiring looks simple enough so I would basically need just a good wiring diagram, what I would need for voltage and amperage. What would be the best way to convert 120VAC to 12VDC and what amperage should I keep it at so as not to let the magic smoke out of the heating elements?

Any and all advise welcome!! I am sure I can do it but I want it to be safe and proper so I would appreciate any help or advise!

 

[madmikeee]

I was thinking I could use an old PC power supply and use the 12v rail. My concern is the amperage draw..It shows a 10a fuse but that only tells me after 10a it would blow..

 

[mike93lx]

are they still in the car and working? Turn them on and throw a clamp meter on the line.

10A at 12v would be very easy for a PC power supply to handle. hook it up with an in-line fuse and you should be good to go. Use a relay and a switch to turn them on and off instead of running full current directly through the switch.

 

[justsam]

Sounds like you ae on the right track with a PC supply. Driving down the road I would expect the voltage to be more like 13.5 VDC so you will be plenty safe with a 12VDC supply.

Is there only one heat range on these seats? If more than one I expect they may series or parallel some of the heating elements, or this could be done with some form of solid state controller. Is there some control module, perhaps with a large heatsink associated with the seat?

If there is no controller, and these are just a heating element, than you really do not need a DC supply. Resistive heating elements really don't care, however it may be cheaper to get an old PC supply as to find a 120VAC to 12VAC transformer @ 10Amps.

 

[madmikeee]

are they still in the car and working? Turn them on and throw a clamp meter on the line.

10A at 12v would be very easy for a PC power supply to handle. hook it up with an in-line fuse and you should be good to go. Use a relay and a switch to turn them on and off instead of running full current directly through the switch.

I am a computer geek by trade so I know many fun things to do with PSU's and that's why I was considering using one as I knew it could do it and secondly I have about 4 of them lying around collecting dust

I was thinking of using the existing buttons on the doors and just mounting them to the drop down center console. I have been told that the relays are necessary. Unfortunately I do not have a clamp meter so determining the amperage would be. This would be a first for me. I am handy at wiring but not super knowledgeable so that is why I am looking for as much info and advise as I can before moving forward.

Thanks!!

 

[madmikeee]

Sounds like you ae on the right track with a PC supply. Driving down the road I would expect the voltage to be more like 13.5 VDC so you will be plenty safe with a 12VDC supply.

Is there only one heat range on these seats? If more than one I expect they may series or parallel some of the heating elements, or this could be done with some form of solid state controller. Is there some control module, perhaps with a large heatsink associated with the seat?

If there is no controller, and these are just a heating element, than you really do not need a DC supply. Resistive heating elements really don't care, however it may be cheaper to get an old PC supply as to find a 120VAC to 12VAC transformer @ 10Amps.

I pulled the bottom and I do not see anything other than the harness. I will be pulling the back out in a day or two so I will check there as well.

I will post the autozone schematics I found for the rear heated seats. I used to be able to read these VERY well but since it has been at least 20 years I am a little out of practice.

 

[madmikeee]

There are other schematics but this one looks to be complete:

 

[BLUE72CAMARO]

So it looks like there is a module that controls these temperature wise using the thermistor to regulate seat temp. I dont see any way of doing this with out having the module out of the car and then the module is going to need to see power on several inputs before it will turn on the seats.

 

[madmikeee]

So it looks like there is a module that controls these temperature wise using the thermistor to regulate seat temp. I dont see any way of doing this with out having the module out of the car and then the module is going to need to see power on several inputs before it will turn on the seats.

OK. Then until I get back into the car and poke around to see what modules are there this is on hold. From what I THINK I see there I could power the modules and the modules would then feed the seats..Therefore all I would have to do is power the modules using the computer PSU and then wire from the module to the seats. Am I reading that correctly?

I knew this wasn't a "simple" project but if it becomes overly complicated I will just leave the heated aspect out of it and still have a cool couch for the basement.

OK found the pic of what the control module should look like. I will poke around and see what I can find.

Thanks guys! I really appreciate the guidance!

 

[MikeF2316]

How cold is it where you're going to put this couch so that you want to do this?

I have some experience with heated seats, but my experience is with Volvo. In 1990 they came out with these high power elements for the front seats. They were about 120 watts per seat. They only had an on-off switch for the driver's control, but they also had a temperature controlled relay. If the seats were left on, the temperature relay would sent full power for a period of time, depending on temperature. Then for 3 times as long as that time it would send a pulsing power, on for about 5 seconds, off for about 20. So that would be the equivalent of about 25 watts. I liked the way they worked so much, I adapted them to my 240.

Earlier ones had lower power elements and a bimetallic type switch built into the seat. On these the seat had to fall below a certain temperature before the heat would switch on.

I have no idea about the power output of your Cadillac heaters, but I'd bet it's fairly high. I would bet that if you hooked both elements in one seating position in series with the 5 volt output on your computer power supply you'd get more heat than you want. I'd suggest you do this as a test and go from there.

 

[wssix99]

This is probably not easy - but it's not rocket science. Just batteries 'n bulbs stuff... with a little more power.

Your seat has two 10 Amp circuits. One for each side. It also has four control modules, one for each side of the seat and one for each seat temperature controller.

A computer power supply won't cut it - but there are LED power supplies on the market that should. You can get a 12V, 20A LED power supply and then run two lines off it to your two control modules, putting a 10A in-line fuse on each line.

Your controllers and seat will have multiple connectors on them and the wire colors will all match the colors on your schematic. The connectors may also have the letters, listed on the schematics, molded on to the plug.

The wires on the schematic that are 0.8 are 0.8mm2 wire, which is equivalent to 18 gauge. The 0.35mm2 wires on the schematic are equivalent to 28 gauge - but, of course, you can use larger.

When you turn the seats on, you'll need to apply 12V to the ignition wire on the seat controllers in order to activate them. (So - you'll need to figure out how you want to do that switch or if you want to just give that wire 12V any time you turn on the power supply.)

You will also need to dig up the schematics for the "Rear Integration Modules," which appear to either contain the heated seat control switches or interface with them. (It looks like the seats aren't just a simple on-off kind of thing.)

 

[madmikeee]

OK I pulled the rear seat last Friday the modules are mounted to the rear seats so it looks like all I have to do is determine the wiring and power supply to use then likely throw in a terminal block for wire organization where I will have to cut, wire a couple of inline 10a fuses and test. I will post a few pics and ask for some help.

 

[toddacimer]

I look forward to seeing photos of this. Cool project

 

[madmikeee]

How cold is it where you're going to put this couch so that you want to do this?
.

You act like it matters



I am man. If I want warm ***** I shall have warm *****.

 

[MikeF2316]

You act like it matters



I am man. If I want warm ***** I shall have warm *****.

You misunderstand. The reason for my question was not overdoing it. A seat heater designed to bring the temperature up quickly when it's subzero might be a little too "good" for an inside, room temperature location. You may not have a warm *****, you may get a grilled *****! And if you use the car's controls, the heaters may not come on at all, as they "think" it's warm enough.