"Short the input " means connecting that input wire to the ground, you can either find out the ground wire from the connector and connect that input wire to it, or simply connect the input wire to any bare metal nearest to ECU.

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99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.