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Free Car Wiring Diagrams & ECU Pin-Outs – Auto Electrician Hayes

Need help with car electrical faults? We provide free wiring diagrams, ECU pin-outs, and electrical schematics for most UK car makes and models. Whether you're repairing your own vehicle or diagnosing a fault, our diagrams can save you time, money, and guesswork.

Why We Provide Free Car Wiring Diagrams

At Auto Electrician Hayes, helping people understand their vehicle’s electrical system is part of what we do best. We believe everyone should have access to clear, accurate information.

Helping DIY Enthusiasts Save on Repairs

If you like fixing cars yourself, our diagrams help you:

  • Identify wiring colours

  • Track live, earth, signal, and CAN wires

  • Locate ECUs, modules, sensors, and actuators

  • Avoid unnecessary part replacements

  • Repair confidently instead of guessing

Backed by Skilled Local Auto Electricians

With years of experience working on UK vehicles, we’ve built a large database of schematics and pin-outs.
We support residents and garages in:

  • Hayes

  • Hillingdon

  • West Drayton

  • Southall

  • Hounslow

  • Harrow

  • Ealing

  • Uxbridge

  • Slough

What Car Makes & Models Are Covered

We provide wiring diagrams for a large range of vehicles, including:

 

Popular Manufacturers

  • BMW

  • Mercedes-Benz

  • Volkswagen

  • Audi

  • Ford

  • Vauxhall

  • Toyota

  • Honda

  • Nissan

  • Kia & Hyundai

 

For Peugeot, Citroën, and Renault, diagrams often require access to manufacturer systems.
We provide support when available — message us to check.

 

 

We make the process simple and fast.

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To find the exact diagram, please send us:

  • VIN / Chassis Number (most important)

  • Make & model

  • Year / registration

  • Engine code (if known)

  • Description of the issue

 

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​You can request your diagram through any method below:

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An ECU pin-out will show:

  • Power supplies

  • Earth/ground points

  • Sensor inputs

  • Actuator outputs

  • CAN/LIN communication lines

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The manufacturers of the French cars Peugeot, Citroen and Renault, have different policies. I have no idea why they have made it difficult for independent workshops. The wire colours and the modules are in code numbers, and DIY people can't remember thousands of codes. I am paying Autodata, Alldata, and HaynesPro, but for some French cars, even I cannot find wiring diagrams if I am in this kind of situation. Please forgive us.   

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How To ask for your vehicle wiring diagrams

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Suppose you like our idea of helping you for free. Like our Facebook Page, please tell your friends to let your friends know on X (Twitter) or Ask A Question on the Google Message system. 

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Wiring Diagrams Request Contact Us

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17 digit VIN/chassis number can be found on the passenger side under the wiper on the windscreen or some cars, or the driver side door pillar or left side door pillar that some vehicles have under the driver foot mat. Sharing this page can help many people!

Note for French Cars

How to Request Your Free Wiring Diagram

Step 1 – Provide Your Vehicle Information

Step 2 – Choose How You Want to Contact Us

Understanding ECU Pin-Outs

Free Wiring Diagrams | Auto Electrician Hayes
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