It'll have about 4 pins it thats it, super simple stuff usually, T1 or T2 short to pin X = will flash a light up on the dash for checking wiring like glowplugs etc.
The cruise versions are great, you can check them via the stalk, press button in & hold down = cruise / a/d light flashes - each stalk option then flashes if its working - or not. The heater controls has something similar too.