2003 S40 my passenger side head light won't work. It is not bulb.

 

If there is no power getting to the bulb - Commonly a bad CEM can be the problem. The relays inside fail. xemodex sells CEM's with upgraded relays. Or the control module is not "coded" to your VIN so a used one would be plug and play unlike most other 99+ Volvo CEMs

 

check out car-part.com for yards near you that may have a gen 1 S40/V40 or check out eBay. The CEM is the gray box with 3 large connectors going to it under the passenger side dash right above the hood release. I got a used CEM for $65 to fix my headlights.

 

I had same problem with left side low beam replaced and still no light .
DUH it was the left side low beam fuse under the hood.....check them