5 minute read|4th Feb 2026
When it comes to car maintenance, having an alternator in full working condition is vitally important.
A key part of your vehicle's electrical system, the alternator converts mechanical energy into electricity to power your vehicle's accessories and systems. Wear and tear, faults, damage and exposure to the elements can all result in alternator problems or failure.
Here, we outline common alternator problems, if it can be repaired and the cost to replace one if it fails.
Get your car serviced or repaired at home
Skip the garage hassle – we come to you for:
£25 off any car service^^
Get a quote
^^T&Cs apply. Offer ends 11/05/26, 9am.
^^T&Cs apply. Offer ends 11/05/26, 9am.
RAC Mobile Mechanics come to you
RAC Mobile Mechanics are rated EXCELLENT and 5 stars on Trustpilot.
Book now
A weak alternator often shows up as dim lights, a battery warning or electrical glitches. These signs shouldn’t be ignored — once the alternator fails completely, the car will soon shut down altogether. Replacing it early avoids a potential breakdown.
Nick Mullender
Lead RAC Mobile Mechanic
Book a diagnostic test with us today
RAC Mobile Mechanics are rated EXCELLENT and 5 stars on Trustpilot.
Book now
The most obvious indicator of an alternator issue is a dashboard warning light. This is often a yellow light, shaped like a battery.
However, there are several other likely signs, including headlights or interior lights appearing dimmer than before or flickering on and off.
Further electrical issues include windows, air conditioning or the entertainment system not working correctly.
Frequent dead batteries or difficulty starting the engine can also indicate alternator problems – as well as more serious problems within the engine itself.
When a driver is traveling at speed, they may also notice a loud grinding noise coming from the engine.
This can then be followed by a smell of burning rubber and the engine stalling unexpectedly.
If you notice any of these signs, it’s advisable to have the alternator checked.
Yes, an alternator can often be repaired, depending on the type and extent of the damage.
If the bearings are worn or noisy, they can be replaced.
Similarly, damaged or frayed wiring can sometimes be repaired without replacing the entire alternator.
And in some cases, just cleaning dirt and debris can help improve the functionality of the alternator and the linked components.
If these don’t fix the problem, then you’ll either need to get it replaced or some alternators can be rebuilt by replacing internal components.
In most cases, it may be more cost-effective to replace the alternator.
When it comes to paying for a replacement alternator, drivers in the UK can expect to pay anywhere from £250 to £800.
However, this can be significantly higher depending on the level of damage to the surrounding area – as well as the make, model, age, and condition of the vehicle.
Looking at the latest RAC Mobile Mechanics data, the average cost to replace an alternator in the UK is £513*.
The average price for parts and labour is around £535.05 according to whocanfixmycar**.
It is worth noting that alternators can be one of the more expensive parts of vehicle to fix or replace.
Source: *Average price quoted for RAC Mobile Mechanics from 01/10/25 to 31/12/25. **WhoCanFixMyCar, November 2025.
The table below represents the average cost to replace a faulty alternator by manufacturer:
Manufacturer
Avg. replacement cost
Audi
£628.59
BMW
£603.37
Citroen
£629.99
Ford
£494.90
Mercedes
£614.57
MINI
£549.36
Nissan
£482.06
Peugeot
£663.06
Renault
£587.78
Toyota
£477.93
Vauxhall
£477.93
Volkswagen
£507.07
Volvo
£539.62
Source: WhoCanFixMyCar, November 2025
High-quality batteries fitted at your home
Skip the garage hassle – RAC Mobile Mechanics come to you!
RAC Mobile Mechanics are rated EXCELLENT and 5 stars on Trustpilot.
Get a quote
