Volvo electrical issues

Hii I have volvo 2007 I'm change speed sensor up the gear but speed metar not working please help

 

Hi
I have volvo 2014 D13
The problem I have, when I turn off the truck, in 3 or 5 min the lights from cab and Sleeper turn off like the battery are volts low, but they are not.
What I need to check??

 

not.
It only happens when I turn off the truck.
the current is cut inside as if the batteries were low voltage

 

OK guys...

We bought a batch of 2021 VNRs secondhand last year. The #1 fuse for the trailer marker lights keeps melting down at complete random; different trucks, different trailers. Anyone have an insight as to what may be wrong? Our shop can't get it figured out.

 

Specifically, no. Generally: See post #7. Replace the light cord. Check the plug connections on the tractor (where the cord plugs into, the screws that attach the wires to the back of the plug) Same for the trailer. Use silicone dielectric grease on the connections. How many in a batch? 3, 25....

 

14. Four are being used in my department and the rest are being beaten to death in construction areas.