Enabling SS seat heaters - another path perhaps?

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elc32955
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Enabling SS seat heaters - another path perhaps?

Post by elc32955 »

Well, I'm in the process of putting SS seats in my Caprice (just have to source a driver's side seat). My wife would love to have her seat heater working.... but we are PPV. We don't have all the optional wiring, BCM programming, control logic, and timed push-button controls. So.....

Rather then try to dive into the world of over-engineered control processes, I had the thought about getting back to basics. When you could solder wires and not worry about to having to program to get your circuit active. Power + conductor = warm toasty tushies.

In other words, what is to stop us from hijacking the wiring directly to the seat heaters and just applying our own voltage completely independent of the BCM, existing wiring & modules, et al? I'm assuming the seat heaters work from 12V and that all the timer does is reduce voltage to slowly reduce the heat level. If we could find the correct wires under the seat to tap into, we could either run switched 12V power (with an actual on/off toggle switch) or perhaps a current-capable rheostat so we can vary the heat level. Our PPV's have blank spots in the radio panels where the seat heater/cooler switches normally reside. Fine spot for a "design modification". Drill the blank spot, put a knob or switch in for each side, hook the heater to 12VDC, ground the seat end, and feel the heat. Does this sound like a logical approach? Yep, you can add in quick disconnects so you can get the radio panel off or break the connection at the seat if you want.

The negative I can see to this idea is that I don't know what the active duration on the seat heater is supposed to be and if there is a burnout hazard for the heating elements if left on too long. I equate this to being the pilot of a 727 in lieu of the 787 Dreamliner. The computers on the 727 were primitive at best, so the pilot had more responsibility to control systems (I.E. flip the switch when needed). The 787 does everything for you and asks you if you want coffee with your timed control functions. Hook to key-switch power to keep you from draining your car battery if you forget to turn the heater off when you're done with the car.

So, does this idea sound viable or have I been in the Florida sun too long this week? I know if you're a purist you have to have everything 100% factory. But, I'm not. I want it to work & be functional and look aesthetically pleasing. I'll settle for working heaters and an unobtrusive knob or toggle switch.

Thoughts? Steve, can you tell us from a schematic read if this is possible and what is the best place to intercept the SS heater wiring? Also is it polarity sensitive?

Thanks
Eric
System Manager and your tour guide for the day. 2015 Caprice w/LFX, former NC DPS staff car. Partial hybrid G8/SS/Camaro SS interior mods, SS MyLink radio upgrade, 2016 Camaro V6 rims, GMPP Malibu chrome exhaust tips, otherwise bone stock for now.
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Mooseman
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Re: Enabling SS seat heaters - another path perhaps?

Post by Mooseman »

I don't think there is a timer except, of course, when the car is shut off, they shut down. In all my vehicles that had heaters, they stayed on as long as the car was running.

One way you could wire them up for low and high heat is be able to switch them from being connected in parallel (high) to series (low). Easy enough to do with relays. Vans like the Montana and Ventures controlled the radiator fans this way with 3 relays. Of course power to the whole works would be controlled by ignition.
2011 Caprice PPV, former RCMP test vehicle, never put into service
Build Thread: http://www.newcaprice.com/forum/viewtopic.php?t=2419
fuzzkill
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Re: Enabling SS seat heaters - another path perhaps?

Post by fuzzkill »

I did this many many many years ago in a car where there was no option to use the factory modules/wiring.

Worked fine with the heater wired to a rocker, and the fans wired to another. However, the seat heaters usually work on PWM, so they will get hot enough to burn your ass and possibly catch fire if left on this way. I am pretty sure there is a thermostat or max duty cycle when using the factory setup that you would be bypassing.
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Re: Enabling SS seat heaters - another path perhaps?

Post by s/c'd cav »

there have been cases of the burning yup and taking out the seat covers
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elc32955
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Re: Enabling SS seat heaters - another path perhaps?

Post by elc32955 »

Yeah, in my older E320CDI the seat heaters get hot enough to cook toast in the high heat mode (3 selections available, system increments the heat down in about 10-15 min intervals via timer logic after you push the button). There's alternatives, one of them would be to always attenuate the voltage to the heaters so that they don't ever get hot enough to burn either you or the seat covers. I need to look at what normal operating voltage for full blast is to the elements along with the GM timing sequence & voltage tree (I.E. low heat is X volts, high heat is Y volts). Another trick I learned years ago is to look at older like carlines (GM family) to see if maybe there's an option there that can be scooped & applied (probably from a salvage yard). They may have a timer in a box that could be hidden & remotely activated, who knows.

We need someone with FSM/TIS access with answers to the above otherwise we're just whistling in the wind on this one I think...

Thanks
Eric
System Manager and your tour guide for the day. 2015 Caprice w/LFX, former NC DPS staff car. Partial hybrid G8/SS/Camaro SS interior mods, SS MyLink radio upgrade, 2016 Camaro V6 rims, GMPP Malibu chrome exhaust tips, otherwise bone stock for now.
mnp
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Re: Enabling SS seat heaters - another path perhaps?

Post by mnp »

So, the SS heat/cool buttons connect on the side of the radio touch screen. The plugs are there on the Caprice touchscreen, however, they are covered up with tape. Maybe, if you get all the modules;
Buttons, heat/cool modules for driver and passenger. It may be possible to add them with all the right hardware. However, I don't know if the harnesses exist on the Caprice for it, my guess is probably not.
Here are several diagrams to maybe help.
heat-cool diagram1.gif
heat-cool diagram1.gif (44.96 KiB) Viewed 1723 times
heat-cool diagram2.gif
heat-cool diagram2.gif (57.69 KiB) Viewed 1723 times
heat-cool diagram3.gif
heat-cool diagram3.gif (63.72 KiB) Viewed 1723 times
heat-cool diagram4.gif
heat-cool diagram4.gif (60.45 KiB) Viewed 1723 times
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