Peugeot Expert Alternator Failure

Sounds familiar. I had similar symptoms on my Expert. It really sounds like your alternator is on its way out. Have you checked the battery voltage when the engine is running? Should be around 14V. A significant voltage drop could mean a bad generator.

Thanks. I'll test the voltage. If it's low, is alternator replacement the most likely fix, or could it be something else like the serpentine belt or starter motor?

A faulty serpentine belt could cause issues, but your symptoms really point to a bad alternator. Check that voltage first, but honestly, prepare for an alternator replacement. Get it checked by a professional workshop to be completely sure. I bet they will find the same thing.

I had a technician check it. They confirmed a defective generator and it needed replacement. Total cost was 960€. Thanks for the help figuring it out.