Need help with wiring seat heating for 997 seats into a 993
10-07-2012, 02:37 PM
#1
Need help with wiring seat heating for 997 seats into a 993
I am installing a set of seats out of a 2006 Cayman into my car. From my research, these are the same seats that were used in 997s. I have the physical installation taken care of and wiring for the 12-way power is just about complete. These were memory seats, so I had a few extra hoops to jump through with wiring adjustments for the driver's side. The last part that I need to complete is to make the connections for the seat heating. I connected 12v to the heaters and they heated up and seemed to stop heating when I got out of the seats ( measured seat temps with IR thermometer). Seats were not installed when I did this, they were sitting on the garage floor with an external 12v source. I have done a fairly extensive search of RL and Planet9 archives to try and figure out connection of the seat heaters, but have not found the specifics I need to make these connections. The questions I am looking to answer are:
What equipment exists in the seats (if any) to regulate temperature? I looked at the PET diagrams and didn't really note anything except for the heater elements themselves in the seat, but this doesn't help to explain the seats not heating when I got out of them. Maybe I was just seeing a faster conductance of heat when my weight was pressing down vs. a relative "insulating property" of foam that's not compressed?
I will be connecting to a switched power source. Any experience out there with which source to tap into?
How do I wire in the switches? Do I need to get a relay between the switch and the heater (any wiring diagrams available?). I have a couple of generic 3-position seat heater switches (middle off, rock either way for hi or lo, 3 connections on back plus a wire for power to the LED indicator) so I would prefer to use these, assuming they will work with this application. If I can't use these switches, what switches do I need and where can I get them?
Is there anything else that I have missed? Any help from those who have done this is greatly appreciated (nile13 has already provided some great info. Thanks Mike!)
What equipment exists in the seats (if any) to regulate temperature? I looked at the PET diagrams and didn't really note anything except for the heater elements themselves in the seat, but this doesn't help to explain the seats not heating when I got out of them. Maybe I was just seeing a faster conductance of heat when my weight was pressing down vs. a relative "insulating property" of foam that's not compressed?
I will be connecting to a switched power source. Any experience out there with which source to tap into?
How do I wire in the switches? Do I need to get a relay between the switch and the heater (any wiring diagrams available?). I have a couple of generic 3-position seat heater switches (middle off, rock either way for hi or lo, 3 connections on back plus a wire for power to the LED indicator) so I would prefer to use these, assuming they will work with this application. If I can't use these switches, what switches do I need and where can I get them?
Is there anything else that I have missed? Any help from those who have done this is greatly appreciated (nile13 has already provided some great info. Thanks Mike!)
10-07-2012, 08:10 PM
#2
Nordschleife Master
I think I can help you out with this. IIRC, there is a red wire with purple stripe coming out of the harness from the seat. This is the power to the heating element. Unlike the seats in a 986/996 (and likely 993), there is no relay in the actual seat itself to control hi/low temp.
In the 987/997, the heat is regulated by a switch on the center console which holds a constant current in the 'hi' temp, and will pulse on/off every 5 seconds in the 'low' temp position. Temp is not controlled by a relay which swaps between serial/parallel config like in other cars. I would use your own switches to power the seat heaters, but you might be stuck in the 'hi' temp position unless you find a way to pulse the current on/off.
I've found that if you just hook up the battery to the seat heater, you can barely tell it's working. However, once the engine is running it heats up fast and well.
I hope I'm making sense. I'm no electrician, but I did some custom wiring to match my old 987 sport seats into my neighbors 986. Then I did my own wiring for my replacement carbon bucket seats, which has heated seat inserts.
In the 987/997, the heat is regulated by a switch on the center console which holds a constant current in the 'hi' temp, and will pulse on/off every 5 seconds in the 'low' temp position. Temp is not controlled by a relay which swaps between serial/parallel config like in other cars. I would use your own switches to power the seat heaters, but you might be stuck in the 'hi' temp position unless you find a way to pulse the current on/off.
I've found that if you just hook up the battery to the seat heater, you can barely tell it's working. However, once the engine is running it heats up fast and well.
I hope I'm making sense. I'm no electrician, but I did some custom wiring to match my old 987 sport seats into my neighbors 986. Then I did my own wiring for my replacement carbon bucket seats, which has heated seat inserts.
Last edited by orthojoe; 10-07-2012 at 09:03 PM.
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