Where is the main relay located in an old Audi A4?
2 Answers
In the old Audi A4, the main relay is located on the left side of the drainage trough, next to the engine control unit. Below is a detailed introduction about it: 1. Introduction 1: The starter relay is a specialized component for compressor startup using single-phase asynchronous motors. 2. Introduction 2: The starter relay is a separate component whose function is to connect and disconnect the attraction coil and holding coil circuits. 3. Introduction 3: The purpose of the starter relay is to assist the motor in starting. After the startup is completed, it automatically disconnects the auxiliary winding to prevent burning out the auxiliary winding coil. When the motor's running winding is powered and transitions to normal operation, the starter relay cuts off the power supply to the startup winding.
I've tinkered with my friend's old Audi A4 before, and the main relay is located in the engine bay. Just remove the black cover (fuse box) in front of the driver's side, and you'll find a bunch of small square components inside—those are the relays. Look for the one labeled 'J271' or marked with a relay symbol, usually positioned near the center. For pre-2007 B6/B7 models, it's typically located here. By the way, plastic parts on older cars tend to get brittle, so avoid using excessive force when removing the cover. If the relay pins have green oxidation, lightly sanding them before reinserting might bring it back to life.
