Relay Locations
Relays are electromechanical switches that allow low-current circuits to control high-current devices.
Common Relays
Section titled “Common Relays”| Relay | Location | Function |
|---|---|---|
| DME main relay | E-box | Powers DME and fuel injectors |
| Fuel pump relay | E-box / behind glove box | Powers fuel pump |
| Fan relay | E-box | Controls auxiliary cooling fan |
| AC compressor relay | E-box | Engages AC compressor clutch |
| Secondary air pump relay | E-box | Powers SAP motor |
| Starter relay | E-box | Engages starter motor |
| Horn relay | Behind glove box | Powers horn |
| Window relay | Behind glove box | Powers window motors |
| Wiper relay | Behind glove box | Controls wiper motor |
Testing Relays
Section titled “Testing Relays”- Swap a suspected relay with a known-good relay of the same type
- Most E46 relays are standard micro or mini ISO relays
- Listen for the relay click when activating the associated system
- Measure coil resistance (typically 50-100 ohms)