Due to the versatility of our products that can be used as ECU or TCU, the freewheel diodes cannot be installed like dedicated TCU systems. They are built into the harness. If you take level 1 harness or manufacture your own, then you must install these boards for the inductive loads.
Especially if it is a PWM solenoid or a low resistance inductive load. Spitronics made it easy by supplying a little Diode board which is compact and can be included in the harness. If it is situated outside the car, care must be taken to seal the unit against water and dirt. You can put silicone on the board before shrinking the sleeve. Silicone will be forced between the components sealing them properly.
Click here to download PDF version of DB1 Positive Diode Board Manual