The service vehicle soon light indicates more then likely an electrical issue when it relates to a lighting issue.
This indicator means a number of different things so we should start with checking the codes and finding out of there are any B codes that will point point us in the right direction.
https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
Then we need to check power coming from the relay and find out if it is steady consistent voltage.
https://www.2carpros.com/articles/how-to-check-wiring
Lastly we need to check the grounds and make sure they are clean and tight.
If we run through all this, I am sure we will turn something up that will either fix the issue or point us in the right direction.
Below is the wiring diagram that will help with this. Thanks
Images (Click to enlarge)
Jun 23, 2021 at 1:17 PM