All 2692 schematics are available on a single page here.

Automotive, car and motorcycle electronic circuit diagrams / circuit schematics

• 12V battery level indicator for car batteries
  
• Car burglar alarm circuit
  
• Flashing light / emergency beacon for vehicle
  
• Headlight guard
  
• Interior light extender
  
• Seatbelt reminder circuit
  
• Two LED trouble light system
  
• Simple car battery voltage monitor
  
• Car Battery Charger, an SCR Design with a 10 Amp rating
  
• Simple Vehicle Loop Detector (inductive loop for driveway etc)
  
• Car power supply unit for digital projects, small car PCs etc
  
• Large capacitor charge "controllers" (Car Audio)
  
• Opendiag OBD-II Schematics & PCB Layout Opendiag OBD-II Schematics & PCB Layout
  
• Hijack alarm
  
• Car acceleration meter
  
• KITT (from Knight Rider) Car scanner using incandescant lamps
  
• Wiper Speed Control
  
• Authentic Looking Knight Rider Led Project
  
• Custom USB tyre pressure monitoring system
  
• Ultrasonic parking sonar electronic circuit diagram using transistors and 4000 series CMOS
  
• Car backup / reversing alarm
  
• Third brake light pulser circuit
  
• Motorcycle battery charger
  
• Motorcycle low battery voltage warning circuit
  
• Motorcycle brake light flasher
  
• Motorctcle turning signal system
  
• Car Timer with Atmel ATiny45 to automatically turn of accessories to prevent flat battery
  
• Car Nicad charger
  
• 12V to 9V car coverter circuit diagram
  
• 3rd brake light circuit diagram
  
• Headlight reminder
  
• Combination lock for car liftgate
  
• 80188XL Engine Tachometer / Race Computer
  
• FCD (Fuel Cut Defencer)
  
• Engine control unit schematics
  
• Fuel injector pulse width monitor
  
• Adaptive Windscreen Wiper Control
  
• Grand Cherokee Off-Highway Lights
  
• Simple car battery charger
  
• Common Ground for Older VPW OBD Circuit
  
• Flashing / pulsing third brake like for cars
  
• Headlight flasher
  
• Speed alert - wireless portable unit
  
• Parking aid senses distance to rear of vehicle
  
• Automatic headlight brightness switch
  
• Economy radar detector
  
• Car OBDII diagnostic interface cable schematic pinout
  
• Car OBD II J1850 PWM, J1850 VPW, ISO-9141 cables schematic pinout
  
• Car Alarm Arming Horn Beep Canceller
  
• Portable CD Player Adapter For Car
  
• Car Battery Charger
  
• Automatic Headlight Brightness Switch
  
• Wireless Auto Tachometer
  
• Low battery cut-off circuit for a car or truck
  
• 20 Segment Expanded Scale Voltmeter including a PCB design
  
• Car Door Keypad Using LIN network
  
• Pseudo car alarm system
  
• Network car controller provides functions for remote door locks, headlight reminder, and car finder
  
• Vehicle Telemetry Platform based on an Arduino
  
• Volvo 164 electric fan thermostat
  
• Digital speedometer for cars with 7-segment display of speed
  
• 12V 300W 4 channel car amplifier schematic diagram
  
• 15W mono car amplifier using TA7227P
  
• 6W mono car amplifier using BA521 or BA532 amplifier module
  
• Speed limit alert
  
• Park-Aid - Three LEDs signal bumper-barrier distance
  
• Headlight Flasher
  
• Car Voltage Gauge with 7-segment readout
  
• Car Water Temperature Gauge with 7-segment readout
  
• Automotive Speed Indicator
  
• Simple but reliable car battery tester using LM3914
  
• Automotive 12V to +-20V converter (for audio amplifier)
  
• Electronic car ignition
  
• Car battery charger with automatic cutoff
  
• Automatic Headlight Brightness Switch
  
• Dome Lamp Dimmer
  
• Loud 10-W Car Alarm Siren