i'm trying to come up with a design to replace an ECU in my car, with a simple relay system for the electric seats.
I have 3 motors, and 6 Switches (Up-Down/Tilt Forward-back/Slide forward/Back).
I guess I can use 2 relays per motor to reverse the polarity of the switches, but that will mean 12 relays under the 2 front seats, and I'm looking for a slightly more compact solution.
Oh and by going for the relay/mosfet route, you can set the relay first then turn on the MOSFET to avoid any arcs etc on the relay contacts hence prolonging the life of the relays.
You can discard the ECU, implement something for the seats; but your car won't run anywhere.
It is highly unlikely the ECU -engine control unit- controls seats. That is usually the job of the BCU -body control unit-
You can implement a microcontroller to respond to the 6 switches and drive a dozen mosfets for the motors, put everything on a printed circuit board and inside an enclosure.
The result will be a personalized BCU with no bulky relays, and can toss the factory BCU.
Or install manually operated seats, with no electrical motors Then you will need no BCU, and no need to make one.
If you have a malfuction, the solution is to troubleshoot and repair, not necessarily to roll your own.
my car has 5 motors in each front seat and 2 in each rear, but its all controlled with high power 3 way switches (centre off, and each side reverses the power to the motor) except the driver seat which has switches and a memory function, which adjusts all 5 motors to any one of 3 presets - and it adjusts the mirrors too
Thanks all - it'a an old (1992) truck, and has no BECM - i'm fitting a set of electric seats, which already have the switched fitted, but I don't have the Controller, hence me 'rolling' my own.
There is a memory function on the Seat controller, but I'm going to bypass that.
I might just replace the existing switches with heavy duty On-Off-On switches. Could be the least problematic in the long run!