Sumner Auto Electrics LTD

Auto Electrician

Unit 1a Guest Rd, Cardiff, CF24 5JS Directions

   Closed today Open Monday 09:00 - 17:00

Why Choose Us?

Family Run Business
Extensive Knowledge
Reliable Service

Business overview

Sumner Auto Electrics are Cardiff's leading auto electrical and hybrid vehicle repair centre. We specialise is all manor of electrical and diagnostic repairs.


Are your car’s electrical systems not working? Visit Sumner Auto Electrics! We have many years of experience and have in-depth knowledge of all makes and models of cars.

How much does it cost?

As you can appreciate, modern vehicles are extremely complex and technical. Without looking at your vehicle it is impossible to tell what is wrong with your car or how much it will cost you to fix. We therefore created our "initial inspection service". We require the car for a full morning or afternoon where we will carry out selective tests to try and form a conclusion or direction for further testing. We charge £90 plus vat (£108.00) for this service and will not carry out any additional work or testing until we have authority from the customer. (Minor fixes included in the charge)

If you have a complex fault then we may conclude from the initial inspection that we need more labour time to find the fault

If you want your car to be diagnosed and rectified correctly give us a call today!

Please note we are extremely busy at present are are usual booked up to one month in advance.


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Initial inspection

Products & Services


Brake and clutches

Cameras and sensors

Car Diagnostics

Car Engine Tuning and Conversion

Car wiring

Catalytic Converters

DPF Cleaning

Electrical faults

Emergency lighting and indicators

Engine carbon cleaning

Engine Diagnostics

Exhaust systems

Fuel economy

Fuel Injection

Heating and air conditioning

Horns, LEDs and dashboard lighting


Starter motors and alternators



  • IMI Accreditation


  • Light Vehicle Maintenance and Repairs Principles, NVQ Level 3 (Institute of Motor Industry)
  • Hybrid Electric Vehicle Repair and Replacement, Level 3 Award (IMI Awards Ltd)
  • Automotive Air Conditioning Servicing and Maintenance (EC842-2006), Level 3 Award (IMI Awards Ltd)


Top guys and great service

Had my Golf booked in just before Christmas. There was a bit of a wait getting the booking as they are busy outfit, but I took this as a good sign. Wasn’t disappointed, Elijah and Mike are great guys who ensure you as the customer are kept in the loop. I had an idea of the issue with the car prior, Elijah confirmed this quickly and Mike ordered a new part for the next day where it was promptly fitted and coded. This is a great local business and I wouldn’t hesitate to use them again if needed.
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Great experience

Amazing from the start. Mike was informative and friendly. My car was sorted the same day. Was worried it would be a huge cost but it wasn’t which made my day. Trustworthy, professional and friendly. Would definitely recommend.
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Fixed my car within an hour, great service

After Green Flag took three months to deliver my car to them after it had had broken down in France, Sumner Auto Electrics managed to fix it within an hour. I was expecting big problems, but they sorted it quickly and efficiently.
I asked them around two months ago if they would be willing to have a look whenever it came, and they were all too happy to wait.
Brilliant communication, great attitude and a very reasonable price.
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Great all round experience. Couldn’t recommend enough!

Local garage recommended taking my A4 to Sumner Auto Electrics for diagnostics due to a misfire that couldn’t be pinned down despite having multiple people do work/take a look. Right from the outset, Eli and Mike were great. After running diagnostics, a plan of action was set, communication was superb (both via text and call). Always kept in the loop and no hidden surprises down the line. For the work done and the price, couldn’t be happier. Have my keys back and the car feels/runs like new.

Can’t recommend and thank these guys enough! Shame there’s only 5 stars. Top, top blokes. Would 100% recommend and return if/when needed👍
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Took my T5 to Elijah with a few issues a couple of garages couldn't diagnose. Elijah diagnosed the issues straight away and got the work done very quickly, within under two days. Very happy and impressed with the excellent service. I will definitely be going back!
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