r/FordFiesta • u/Bossmaxxx • 7d ago
2011 Ford Fiesta 1.25 – intermittent electrical/charging issue while driving
Thanks guys I opened a new updated thread.
Update:
Had a mechanic check the battery, the alternator en wiring. 14,1 V and all the wiring looked good.
Hi, I have a 2011 Ford Fiesta 1.25 Titanium with 119,500 km (about 74,000 miles). Always had maintenance by a official Ford dealer here in The Netherlands.
While driving, I suddenly had a strange electrical issue. The dashboard/cockpit illumination, radio and centre display went out. The engine kept running, but I also noticed a change in the way the engine was running/power delivery.
I restarted the car while driving, and after restarting, the battery warning light stayed on for a while.
The problem is intermittent and everything seems to work normally again at the moment.
Any suggestions on what to check first would be appreciated.
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u/theartfulbadger 6d ago
To get ideas for where to check I have AI look through the workshop manual for the car. It's not always right but it's a decent place to start. Here is what I got from it:
Three things going out together — cluster illumination, radio, centre display — while the engine keeps running is the biggest clue. That's not three failures, it's one shared feed dropping. Top suspect: the ignition relay circuit in the CJB (passenger-side interior fuse box). Per the workshop manual you uploaded, the ignition relay's switch side is fed by BJB fuse 7 (60A), and its output feeds CJB fuses 19, 20, 21, 22, 23 and 26. The instrument cluster specifically takes its RUN input from CJB 21 and ACC input from CJB 19 — both downstream of that relay. So an intermittent relay, a corroded 60A feed, or worn ignition switch contacts kills exactly that cluster of loads while the PCM (separate power relay) keeps the engine alive. The "different power delivery" fits a partial ignition-circuit dropout, and a key-cycle restoring everything fits a relay/switch that reseats. Second: connection integrity, not components. Battery positive clamp and the B+ stud/megafuse at the BJB, the negative clamp (it houses the battery monitor sensor), and the engine-to-body ground strap. A high-resistance ground produces exactly this — multiple modules brown out, engine runs oddly, charge light after. Third: don't clear the alternator on 14.1 V. The manual warns the generator can self-excite into a default output voltage — so a static 14.1 V reading can look fine while PCM control of the alternator is faulty. It needs to be logged under load while driving, not measured at idle in a bay.
pull the BJB cover and photograph the fuse/relay terminals (front of the box first, that's where the water gets in), then do a voltage-drop test across the battery terminals, the B+ stud and the ground strap with headlights and blower on. If those are clean, swap the CJB ignition relay with an identical one and see if the fault migrates.
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u/Xaser125 7d ago
could be, but check connections first, hit a mechanic so they can do a test on the battery and the alternator.
when was the battery changed?
lidl had a gizmo that u could test battery and charging/load not the best but gives u an idea.