Alternator regulator replacement

The consumer’s issue:

“I bought a luxury saloon in June 2003, and in July 2021, repairs to the brake pipes and the steering knuckle on the front axle were completed by a franchise dealership due to my car failing its MOT at another garage.

Upon collection of my vehicle and during my drive home, a red warning light illuminated on the dashboard, indicating an electrical fault. The dealer therefore suggested that I take my vehicle for its MOT as it may have been a battery fault. I therefore took my car to a garage, but the MOT had to be abandoned, as the engine could not be started.

The fault was eventually found to be the alternator regulator, which was replaced by the dealership at a cost of £830. However, since there were no indications that the regulator was failing prior to visiting the business, I am looking for the dealership the full cost of repairs.”

The accredited business’ response:

  • We carried out brake pipe repairs to the customer’s vehicle, as it failed an MOT at another garage.
  • The work was performed as agreed and authorised by the customer, who then took the car for a MOT re-test at the same garage.
  • During the MOT re-test, the car’s engine cut out and would not start. We therefore had the vehicle recovered back to our workshop on the customer’s behalf, and identified a fault with the alternator regulator, which was unrelated to the previous repair.
  • The replacement was authorised by the customer, and after these repairs were complete, we carried out the MOT for the customer so they would not have to return to the other garage for a re-test. We have provided documentation of the work carried out and the paperwork showing the MOT fails at the other garage.
  • We would also like to point out that the customer’s vehicle was first registered 18 years ago, and it is therefore not unusual for cars of this age to require additional work.

The adjudication outcome:

  • The Motor Ombudsman adjudicator reviewed the evidence provided by both sides, and documentation, such as job card, diagnostic invoices, and MOT certificates.
  • The adjudicator explained that, while it had been established there had been a fault with the alternator, the burden of proof was on the consumer to demonstrate that this was directly related to the workmanship of the business.
  • On this point, it was noted that there was a lack of independent, documented technical evidence to support the conclusion that either the diagnostic work or previous repair work by the business had been carried out with a lack of reasonable skill and care, which then resulted in the problem with the alternator.
  • The adjudicator also determined that, considering the age of the vehicle, and mileage covered at the time of the MOT failures, it was just as much likely the alternator fault was a consequential fault of the previous heavy brake pipe corrosion which required repair.
  • The adjudicator highlighted that the appearance of a fault following the repair of another issue, does not automatically mean the business failed to carry out the previous repair with the reasonable skill and care required.
  • Furthermore, there had been no third-party diagnosis or evaluation determining that the repairs by the business had been insufficient or caused the alternator fault that was discovered.
  • As a result, the adjudicator did not find a breach by the business of The Motor Ombudsman’s Service and Repair Code, and made the decision to not uphold the case in the consumer’s favour.


  • Both the business and the consumer accepted the adjudication outcome, and the case was then closed.