Relays on the Model 87 Porsche 928 Cars Porsche 928S Model 87 Relay Chart Relay Number Function I - II Rear Window Heater III Not Used IV X - Relay V Turn Signal Flasher VI Window Lift VII Wiper Interval VIII Defrost IX Auxilairy Cleaning Pump X Fresh Air Blower XI Supperessor XII Horns XIII Fog Lamps XIV Starter XV Kickdown XVI EZF XVII ABS XVIII Engine Coolant Air Flap XIX Headlamp Cleaning System XX Fuel Pump XXI Interior Lamp XXII Backup Lamp XXIII - XXIV Light Combination Relay XXV LH-Jetronic XXVI Not used