Ford Fiesta Alternator: Specs, Fitment & Common Faults
A genuine fitment trap between engine variants, plus the simple multimeter test that confirms whether it's really the alternator before you replace it.
Illustration for editorial purposes
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OEM Part Number: H1BT-10300-GB (as quoted in catalogue listings — confirm via VIN) — aftermarket alternators Bosch 0 986 082 220 / Denso DAN1119
| Alternators (aftermarket) | Bosch 0 986 082 220 (120 A, rigid multi-rib pulley, 6 ribs, 49 mm, reman exchange, PL174 plug with B+ M8 and LIN, direct mounting, 176 mm long, excludes vacuum pump, core charge GBP 23.51); Bosch 0 986 084 230 (150 A, freewheel clutch pulley, 6 ribs, 54 mm, reman exchange, PL174 plug with B+ M8 and LIN, double pivot mounting, 192 mm long, excludes vacuum pump, core charge GBP 47.03); Denso DAN1119 (120 A, freewheel clutch pulley, 6 ribs, 54 mm, new, OE quality); Denso DAN930 (150 A, freewheel clutch pulley, 6 ribs, 54 mm, new, OE quality); Hella 8EL 015 630-121 (120 A, freewheel clutch pulley, 6 ribs, 54 mm, new, core charge GBP 6.91); Lucas LRA03470 (150 A, freewheel clutch pulley, 6 ribs, 54 mm, reman, plug 0213 with M8 B+ and COM/LIN2, core charge GBP 25.12); AS-PL A6010 (120 A, freewheel clutch pulley, 6 ribs, 54 mm, new, PL_3402 plug); Ridex 4G0866 (120 A, freewheel clutch pulley, 6 ribs, 54 mm, new, B+ M8 with COM/LIN2, excludes vacuum pump) / AS-PL A6882S (120 A, freewheel clutch pulley, 6 ribs, 49 mm, new, PL_2305 plug); AS-PL A6938S (120 A, freewheel clutch pulley, 6 ribs, 49 mm, new, PL_2305 plug); AS-PL A6789S (150 A, freewheel clutch pulley, 6 ribs, 52 mm, new, PL_2305 plug); AS-PL A6792S (150 A, freewheel clutch pulley, 6 ribs, 49 mm, new, PL_2310 plug); AS-PL A3893S (120 A, freewheel clutch pulley, 6 ribs, 53 mm, new, PL_2305 plug); Rotovis 9091393 (120 A, freewheel clutch pulley, 6 ribs, 49 mm, reman, COM plug); Rotovis 9091381 (150 A, freewheel clutch pulley, 6 ribs, 49 mm, reman, COM plug); HC-Cargo F 032 116 818 (150 A, 6 ribs, 52 mm, new, PL174 plug, core charge GBP 7.31) |
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| Outputs & variants | On the 2008-2017 car the split is 80 A (rigid pulley, 49-54 mm, older 1.25 and 1.4 petrols), 120 A (rigid 49 mm pulley on the Bosch-pattern units, or freewheel 54 mm on the Denso-pattern units) and 150 A (freewheel 54 mm, the higher-demand petrol and TDCi diesel installations). On the 2017-on car almost everything is a freewheel clutch pulley at 120 A or 150 A on a 49 to 53 mm pulley, plus a separate 48 V 210 A unit for the 1.0 EcoBoost mHEV. |
| Genuine (OE) numbers quoted | AS-PL A9023 quotes 2S6T10300FA; AS-PL A6010 quotes 104210-3513; AS-PL A3259 quotes TG12C145; AS-PL A3267S quotes TG15C186; Rotovis 9091397 quotes H1BT-10300-GB; Rotovis 9091393 quotes H1BT-10300-EC; Rotovis 9091381 quotes H1BT-10300-FC; AS-PL A6938S quotes 104211-4091; AS-PL A6882S quotes 104211-3812; AS-PL A6792S quotes 104211-9012; AS-PL A6789S quotes 104211-9540; AS-PL A6778S quotes 104211-9361; AS-PL A3893S quotes TG12C249; AS-PL A01202(SEG) quotes 0127813050. |
| Fitment notes | Match the pulley type and diameter to the old unit because 49 mm rigid and 54 mm freewheel versions exist at the same amperage; several Ridex units are marked as not suitable for engines where the alternator drives a vacuum pump; Bosch and Lucas exchange units carry a refundable core charge and Bosch recommends fitting a new belt at the same time; the 48 V unit fits only the mild-hybrid 2020-on EcoBoost and is not interchangeable with 12 V parts. |
A Genuine Fitment Trap: Engine Variant Matters More Than You'd Expect — Ford Fiesta Alternator
Worth knowing before ordering: the alternator fitted to the Fiesta's 1.6-litre non-turbo engine is a different part entirely to the one used on the 1.0 EcoBoost or the 1.6 Turbo fitted to the ST — they are not interchangeable despite superficial similarity, and the alternator's physical location and mounting differs enough between these engines that fitting the wrong one simply won't work. Always confirm your exact engine code before ordering rather than assuming by Fiesta generation alone.
A Simple Test to Confirm the Alternator Before Replacing It
Before paying for a replacement, it's worth confirming the alternator is genuinely the problem: with the engine running, a multimeter across the battery terminals should read roughly 13.8-14.5V — readings notably below this suggest the alternator isn't charging properly, while readings significantly above 14.5V suggest a failing voltage regulator, a different (though related) fault. A whining noise that gets noticeably louder when you switch on heavy electrical loads (headlights, heated rear window, air conditioning on full) is also a strong practical indicator worth trying before assuming the worst.
Ford Fiesta Alternator: Often Blamed on the Battery Instead
On the Ford Fiesta, a weak battery and a failing alternator produce almost identical symptoms at first — dim lights, slow starts, a car that won't hold charge — which is exactly why so many people replace the battery, only to be back at the garage a few weeks later with the real culprit untouched.
Ford Fiesta Alternator: Watch: Replacing It
Mk7 1.6 petrol
Ford Fiesta Alternator: What It Does
The Ford Fiesta's alternator generates electricity while the engine runs, charging the battery and powering the car's electrical systems directly. A healthy alternator means the battery is mostly there for starting the engine and covering brief demand spikes — not for actually running the car's electronics on its own.
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Ford Fiesta Alternator: Warning Signs, DIY Difficulty & Aftermarket Advice
These are the same regardless of make or model — see our full Alternator Guide for symptoms to watch for (plus a genuinely useful two-minute test to confirm it's not the battery instead), confirming the right amperage and fitment against your VIN, and which brands are worth trusting.
More Ford Alternator
The same part, covered across other Ford models.