One problem related to dash wiring has been reported for the 2006 Volvo S40. The most recently reported issues are listed below.
1. Severe summer thunderstorms and rain. 2. Drove approximately 1 mile and right blinker stayed solid green after turning. Drove about a mile further onto highway entrance ramp and car indicator lights flashed abs brake failure and air bag failure, then all car instruments (gas gauge, speedometer, tachometer, etc) failed for about five minutes. Instruments came back on but abs brake and air bag failure continued to flash for about 1 more minute. Drove directly to dealership. 3. Service department took the car right in and applied grease to the harness connector which should alleviate problems as they are known to get wet and corrode. Please note this is a 2006 model as I have read on the website that the 2004 model has the exact same problem. Additionally, driver side door locks and power windows intermittently inoperable leading up to this failure. Had a scheduled appointment to remedy this situation but brought the car in early as the car was inoperable without instruments.