1 Check the terms and conditions
Check the terms of your warranty carefully so you know exactly who is providing the cover. You also need to be aware of any exclusions in the warranty.
2 Contact the warranty provider
Contact the warranty provider and quote the section of the policy document that makes it clear that the remedial work you need doing is covered.
If the warranty provider refuses to arrange, or pay for the repairs, ask it to set out in writing exactly why it considers that it is not responsible.
3 Don't be fobbed off
If the warranty provider doesn’t give a good reason for refusing the claim or doesn’t respond to you at all, get quotes for carrying out the work.
Send these to the warranty provider explaining that if it continues to refuse to carry out the work, you'll claim the cost back from them of having the work carried out.
4 Taking your complaint further
If the warranty provider is the dealer that sold you the car, you may need to take it to court. Check first though whether the dealer is a member of any trade association.
If so also check whether that association offers any sort of alternative dispute resolution process. If it doesn’t then you could consider taking court action.
Court action should always be a last resort and you should make sure that you have taken all steps to resolve the dispute.
In England and Wales there's a Practice Direction on Pre Action Conduct which helps you with this process by setting out the steps you should take.
If the warranty is underwritten by an insurance company, you could refer the dispute to the Financial Ombudsman Service.
You'll need to have exhausted the warranty provider’s internal complaints procedure first, or be able to show that more than eight weeks have passed since you referred your complaint to the insurance company and that the matter remains unresolved.