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BMW

Genuine BMW Battery Negative Cable 380mm | Earth Strap / Ground Wire / Chassis Ground Lead | Fits E30 E36 E46 E34 E39 E32 E38 E31 Z3 Z4 (330i M3 750i Z4 M 3.2) | OEM 12421737755

Genuine BMW Battery Negative Cable 380mm | Earth Strap / Ground Wire / Chassis Ground Lead | Fits E30 E36 E46 E34 E39 E32 E38 E31 Z3 Z4 (330i M3 750i Z4 M 3.2) | OEM 12421737755

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Heads-up on cancellations & returns: if you cancel an order or return an item, you won't get back 100% of what you paid. We apply a 10% restocking fee, the outbound shipping is non-refundable, and we have to pass on Shopify / PayPal payment processing fees; these aren't returned to us when we refund you. International orders also lose on exchange-rate spread in both directions. If the original packaging is damaged or missing, a reboxing charge applies. For international orders specifically, if you refuse to pay our shipping invoice or supply a prepaid label after placing the order, the same deductions apply. We're upfront about this — please be sure of your purchase before ordering.

BMW 380 mm Earth Bonding Lead, Negative Return Cable, Chassis Earthing Strap | OE Part 12421737755

Restore crisp starting and stable charging on your classic BMW with this authentic factory earthing lead. This 380 mm negative pole cable links the battery to the body shell for a clean chassis return and low resistance across the electrical system. Direct replacement, OE build, BMW part number 12421737755.

We have installed this on our own builds and countless customer cars with excellent results. Owners report quicker cranking, steadier voltage, brighter lights and fewer random electrical gremlins after swapping out a tired, corroded strap. Ideal preventative maintenance when refreshing a starter motor, alternator or battery.

Why this OEM lead is a smart upgrade

  • Factory-spec fit for fast, hassle free installation
  • Restores a strong chassis return path for consistent ignition performance
  • Reduces resistance and voltage drop caused by aged or oxidised earth links
  • Correct 380 mm length with robust copper core and OE terminals
  • Perfect for reliability upgrades, restoration work and routine servicing

Vehicle applications

Suits a wide range of BMW E chassis models and body styles:

  • 3 Series
    • E30 saloon, coupe, convertible, touring
    • E36 saloon, compact, coupe, convertible, touring
    • E46 saloon, compact, coupe, convertible, touring including 330i and M3
  • 5 Series
    • E34 saloon and touring
    • E39 saloon and touring
  • 7 Series
    • E32
    • E38 including 750i
  • 8 Series
    • E31
  • Z models
    • Z3 E36 roadster and coupe
    • Z4 E85 and E86 including Z4 M 3.2

Tech details

  • Length 380 mm
  • BMW OE part number 12421737755
  • Genuine BMW component for long term durability and correct fitment

When to replace your earthing lead

  • Slow or intermittent cranking, especially when cold
  • Dim lights or fluctuating voltage at idle
  • Visible corrosion, cracked insulation or stiff, heat damaged cable
  • Intermittent electrical faults after engine or battery work

Professional fitting

Want it installed properly the first time. Book our expert workshop. MJ Modifications, Warwickshire. Request a quote at info@mjmodifications.co.uk.

Compatibility check

We verify fitment before dispatch. Add your UK registration or the last 7 digits of your VIN at checkout so we can confirm this part suits your vehicle.

Warranty

Two year manufacturer warranty for UK customers and one year for international customers when a VIN is provided at checkout on compatible vehicles.

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