Quick answer

Verified

Applies toFocus - B4 (C307 post-MCA) · Built from 29 April 2010Focus (2010) · Built 6 December 2010 to 7 March 2011

Fuse
20
Amperage
15A
Fuse box
Engine compartment
Location
In the engine compartment

Where is the fuse box?

Engine compartment fuse box

In the engine compartment

Our source doesn’t describe how to open this fuse box. Check your owner’s handbook.

We haven’t drawn a schematic of the engine compartment fuse box for this version yet. Use the fuse and relay numbers on this page and the legend on the fuse box to find the right position.

Where to look

  • 20

    In the engine compartment

    Fuse ·15A · Horn

    Position not shown on the schematic. Find fuse 20 on the fuse box legend.

Always confirm the number against the legend on the fuse box cover before pulling anything.

How to replace the fuse safely

  1. Switch off the ignition and all electrical equipment. Take the key out, or move a keyless fob away from the car.
  2. Open the fuse box and find the fuse using the number on the cover legend or the chart on this page.
  3. Pull the fuse straight out with the plastic fuse puller (usually clipped inside the fuse box) or fine-nose pliers.
  4. Look at the metal strip inside the fuse. A broken or burnt strip means it has blown.
  5. Fit a new fuse with exactly the same amperage rating. The number on top and the colour should match.
  6. Refit the cover, switch on and test the component.
  • Never fit a fuse with a higher amperage rating than specified. It can let wiring overheat.
  • Never bridge a fuse with wire, foil or anything else.

Fuse keeps blowing?

A fuse that blows again straight away is doing its job. Something on that circuit is drawing too much current. Common causes are damaged wiring shorting to the bodywork, a failing motor or socket, water getting in, or a faulty accessory. Fitting fuse after fuse, or a bigger fuse, won’t fix the fault and can overheat the wiring. Have the circuit tested by an auto electrician.

Not the fuse? Check these next.

  • Horn unit itself

    Horns sit at the front of the car, exposed to water and road salt. A corroded horn or connector is a common cause.

  • Steering wheel contact

    The horn pad connects through a contact inside the steering wheel. If the horn works only at some wheel positions, that contact may be worn.

  • Shared fuse

    If other items on the same fuse have also stopped, suspect the fuse or its supply rather than the horn.

Sources & verification

Applies toFocus - B4 (C307 post-MCA) · Built from 29 April 2010

Status
Verified
Specification
UK market
Last checked
14 October 2026

Applies toFocus (2010) · Built 6 December 2010 to 7 March 2011

Status
Verified
Specification
UK market
Last checked
14 October 2026
  • Manufacturer manual listingFord UK — 2010 Focus (2010) owner manuals · Ford Motor Company · Owner’s Manual (Vehicles Built From: 06/12/2010 Vehicles Built Up To: 07/03/2011) · Accessed 14 October 2026
  • Manufacturer manual listingFord UK — 2011 Focus (2010) owner manuals · Ford Motor Company · Owner’s Manual (Vehicles Built From: 06/12/2010 Vehicles Built Up To: 07/03/2011) · Accessed 14 October 2026
  • Owner’s manualFord Focus (2010) Owner’s Manual — CG3568en, edition 09/2010 · Ford Motor Company · Fuse specification chart — Engine compartment fuse box (pp. 175–177); Fuse specification chart — Passenger compartment fuse box (pp. 179–180); Fuse specification chart — Load compartment fuse box (pp. 180–182) · Accessed 14 October 2026

Fuse layouts can differ between trim levels and optional equipment. Always confirm against the legend on your fuse box.