Genuine Volvo S40 Fuse Box

Volvo S40 Fuse Box Parts and Q&A

• Relay Box
  30870947
  Q: Where can you find Fuse Box and Relay Boxes, and how should they be handled when blown or faulty on Volvo S40?

  A:

  Fuses can be found in the central fusebox (on the left side of the engine compartment) and in the Central Electrical Module (CEM) (underneath the glovebox). If a fuse blows, the electrical circuits protected by that fuse will not be able to function, with particular fuse locations and protected circuits depending on the vehicle specification, model year and country. To remove a fuse, turn off the ignition, remove the fusebox cover or lower the CEM and use the provided plastic removal tool to pull out the fuse in question - an indication of a blown fuse is a broken or melted wire inside. Always replace a blown fuse with one of the same rating to prevent fire hazards and avoid replacing a fuse several times without having to identify the underlying problem. Persistent fuse blowing indicates a fault in the protected circuit and troubleshooting can be done by switching on things one at a time to isolate the problem. A blown fuse could also occur due to a short circuit in the wiring, so look for trapped or frayed wires and damaged connectors. Only blade-type fuses should be replaced by DIY mechanics, and blown large fusible links are a good indication of serious electrical faults that require professional diagnosis. Relays are electrically-operated switches that provide the ability to switch heavy currents remotely, to have multiple control inputs, and to provide timer functions. If there is a fault in a relay circuit, then the relay itself is possibly at fault; a simple check to do this is to listen for a click when the item is switched on. Most relays have four or five terminals that supply current and output, and testing should be done so that all connections will produce the expected voltage. Substitution with a known good relay is the ultimate test, however, caution is required because it is possible that similar looking relays are not identical. Relays are found in the fusebox on the passenger side on the engine compartment and in the CEM and to remove a relay, be sure the ignition is off before removing the relay from its socket and firmly pushing in the new relay to re-fit.