Electrical gremlins
A slightly weird problem cropped up last week with my 2011 Ford Mondeo 2.0 petrol: the dashcam blew a fuse and died. Everything seemed to continue working and I drove to work in blissful ignorance of what was to come. The dashcam was plugged into the cigar lighter and the socket was now dead, as was the one mounted in the rear armrest's centre console.
Referring to the Haynes manual, at the top of the page was this disclaimer: “At the time of writing, certain wiring diagram technical information was unavailable. As a result, these diagrams are a representation set covering most major electrical systems typically encountered on this model range.” I contacted Haynes for a revised edition but all they could say was that they would refund my purchase. I found the fuse shown on the diagram, which was fuse 7 supplying both sockets. However, the diagram said fuse 7 was 7.5 amps and was for the steering control unit. The layout didn’t even look anything like my passenger fusebox.
Back to the old-fashioned way of doing things, with my better-half sitting in the driver’s seat holding the multimeter, and with the engine running and me wedged under the dash/glovebox. With a diagram found on the internet, I worked my way along towards fuse 7; fuses 1 to 6 read 13 volts at both ends, but 7 showed voltage only at one end. Taking it out, it was a blown 20-amp fuse. I switched off the engine and, with no 20-amp fuse to hand, soldered four strands of 5-amp fuse wire across it and reinserted it, which restored power at the cigar lighter.
The centre display on the dash now said ‘Press OK to reset trip’. I pressed it and nothing happened. I tried pressing it again and again. Still nothing. In frustration and annoyance, I pressed OK and held it down. The display changed to ‘Hold down OK button’ and the trip miles that I had done that week vanished and were reset. Releasing the OK button, it once more instructed me to press it to reset the trip. I switched it all off and left it, but all the way to work the next day it kept asking me to reset it. I tried this several times by holding the button down, to no avail.
The following week, my better-half once more agreed to help me as I squirmed back under the glovebox. Fuses 1 to 7 all had voltage, while numbers 8, 9, 10, 11 and 12 had no voltage at either end. I looked these up and they were listed as headlamps, windscreen washers and reversing lamps, all of which were working perfectly. Did fuse 10 really control the reset fault or was this a red herring? Were all five fuses for a sunroof or diesel heater and assorted variants that didn’t apply to this basic petrol vehicle? Even if I found out what these fuses were for, would it be anything to do with the weird reset display fault?
Thinking outside the box, I decided to check the engine fusebox, which looked closer to the Haynes diagram. With the engine running, I measured each fuse at both ends. All the old-fashioned fuses measured 13 volts at both ends. The cleartopped ones let me shine a torch through and see that they were intact.
I cut half a post-it note to cover the display and went to work. The top half of the display had already been covered for a couple of years to hide the digital clock display. There are two digital clocks in this car, one for the left and one for the right. Both are covered over and a real clock glued to the dash instead. I resigned myself to losing the MPG function as it could no longer be displayed with the constant ‘Press the reset button’ in the middle of the display. Hugh Rogers
I will first start by thanking you for the exhaustive information supplied. This does make giving a reply much easier. I’ll start by noting that the passenger fusebox can be made slightly more accessible by releasing the fixing and dropping the fusebox down into the passenger well.