Ozzy99

Fiesta 2013 F3(reverse fuse) blowing.

Recommended Posts

Hi All,

I have 2013 facelift Fiesta that is blowing the reverse circuit fuse F3(7.5Amp). The fuse blows immediately some times, but other times the reverse lights and all 4 rear parking sensors work perfectly ok for a few minutes before the fuse blows again.

I would consider myself and competent electrical person, but this one has me stumped, and the Haynes manual seems to be lacking some important wiring info!

So far I have done the following, but without luck...

  • Disconnected both rear lights, mainly so I can measure from fuse to earth without having the bulbs appear as shorts when using ohmmeter.
  • I’ve tested switch in gearbox, and it works fine with no short to earth
  • I’ve measured circuit to ground and get less than 1 Ohm (bulbs removed), and wiggled all the various looms, and so I’m as confident as I can be there is no accidental wiring loom short.
  • Car has reversing sensors, so I disconnected the loom under the rear bumper to isolate all 4 sensors
  • I even traced the blue wire for the reversing circuit into the BCM (Body Control Module), behind glovebox, and pulled the wire out of the connector, (grey connector with white pull lever) so there was no way the short could be coming from there.

However fuse still blows, and more interestingly, the rear lights and parking pilot system seemed to work ok, for a few minutes before fuse blew again.(even with the blue wire to BCM disconnected) 

So my conclusion is that there must be more than 1 circuit being used around the BCM. I did look for a standalone rear parking sensor module, but another post seemed to suggest the rear parking sensors are possibly controller directly from the BCM.

Everything is pointing towards the BCM still, but I guess this will be expensive just to fix rear parking lights/sensors.

Does anyone have any other ideas, or an understanding of where this blue wire may go? Are there 2 separate reverse circuits that use the blue wire?

If it is the BCM any ideas on likely costs?

Any help much appreciated

Share this post


Link to post
Share on other sites
 

I think my 1st message probably rambled on for too long! So hopefully a very simple question for anyone who has access to wiring info for 2013 fiesta face lift edition...

Where does the blue wire from the output of the gearbox reverse switch go?

I know it goes to rear reverse lights, and I have found 1 wire going into BCM, but I’m missing another connection somewhere (most likely related to the rear parking sensor option).

I’m considering just pulling (disconnecting) the wires that enable the rear parking sensors so I get just get rear lights working again.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now