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      11-10-2021, 02:07 PM   #444
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Drives: E90 320d LCI
Join Date: Oct 2012
Location: Brasov, RO

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Originally Posted by Red Racer View Post
Retrofitting E90 Seats into a Hot Rod or other car without a computer (KCAN).

Just wanted to add to this great discussion. I have been reading this for over a year while I build a 1968 Mustang Fastback. I have a set of 2008 M3 seats in dark red that matches the cars Shelby strips.

Obviously, the car does not have a KCAN signal or feed to keep the Driver's seat activated. I have been searching for a solution for quite a while and I think I found one...

I started with a 5v source @ 1-2 amps to trigger the KCAN feeds into the seat.

1st test included simply touching the wire to the feeds in the seat...result: seat worked for about 30secs to 1 min. By disconnecting and reconnecting, I was able to get another 30secs to 1 min.

2nd test, I found a common LED power source for retrofit automotive tail lights. It dropped the 12v feed to 5v - LEDs dont need full power. So by using an early mustang retrofit module where the LEDs sequenced to turn on each individual light bulb as the turn signal is activated, (the new mustangs, this feature is built in) I created a pulsing 5v signal. Low and behold, I found / created a signal that the seat saw as a KCAN Signal.

Result... the seat worked continuously while the ignition was active. All the other functions work when wired as others here have described.

For the Heated Seat function, I found a 10min timed relay. When a 12v signal was applied (via momentary switch), it would trigger the relay sending power to the heating element for 10mins then disconnect. If you wanted more time, hit the momentary trigger switch and the cycle started again. FYI... these relays come in many different times, 1 min, 2mins, 5mins... etc.

Just wanted to share my 2 solutions...
Just to add: I discovered by myself another solution:
By grounding he CAN signal every 10 seconds, the powered seats keep working
I will do a simple arduino program (similar to blink a led) that will turn a PIN low every 5 seconds.
I measured and there is hardly any power draw (less than 1mA), so no relay should be required
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