Is in Volvo s 40 1999 relay for windshield wipers?

Yes, the 1999 Volvo S40 has a relay for the windshield wipers. It's typically located in the fuse box under the dashboard or in the engine compartment, depending on the specific configuration. If the wipers are not functioning properly, checking the relay and associated fuses is a good first step in troubleshooting the issue.