The battery is flat every morning but charges normally during a drive.
A parasitic load keeps drawing current with the ignition off.
Suggested test plan
- Confirm the drain with a clamp meter.
- Isolate circuits with the fuse-pull test.
- Test the suspect relay for stuck contacts.
- Repair and re-measure key-off current.
Safety: 12 V systems are low voltage but can still cause burns and fire. Disconnect the battery before working on wiring and never short a battery terminal.
Parasitic drain diagnosis relies on measuring current, not voltage. A relay with welded contacts is a classic cause.