I have a 2006 S40 T5 FWD manual which started developing electrical issues a few weeks ago. It started on the last day of a 3 day road trip with a flashing "info" light followed by the digital readout screen going blank , Along with all the gauges going off. I turned the car off and back on and the issue went away for about a week, and it has since returned multiple times. The gauge cluster will go completely dead. When it does this , things like the turn signals still work, however there is no indication they are working while sitting in the driver's seat. The center console/radio still work during these episodes as well. I'm wondering if it's an electrical ground issue , just wondering what you guys think ! Thanks In advance.

 

Can you wiggle the wiring under the dash to get it to malfunction?

 

I had this exact problem where the dash would completely turn off and come back on while driving like you mentioned. I would also all the warnings flashing, like ABS, SRS, etc. Never lost power, acceleration, or radio. I would always pull over and it would be okay, sometimes for weeks or months at a time with no issues. Eventually it was all fixed through two things

1. Replaced battery had low charge / wasn't keeping consistent charge. This seemed to help, but the issues started once again months later, so not 100% sure this helped.
2. We found the wiring harness from the Dash had a tear in it. Seemed to be shorting out depending on how it was positioned, which made it extremely difficult to replicate at the shop. Once this was replaced I haven't had an issue since, over 2 years now.

Tried looking for the actually wording from Volvo, but can't find it in my files. It might be in my glovebox.