Description
Genuine BMW glow plug wiring harness (engine, glow module) for the N57 3.0-litre six-cylinder turbo diesel. This is the loom that runs from the glow plug control module down the side of the engine and terminates in the six individual glow plug connectors, plus the multi-pin plug back to the module.
BMW part number 12517808257. Supplied new, genuine BMW - not a pattern or repair-kit part.
Why replace the glow plug harness?
This loom sits directly on top of a hot diesel engine and gets cooked through every heat cycle. The individual glow plug connectors are the weak point: the plastic goes brittle, the locking clips snap during service, and the terminals corrode or lose tension. The usual symptoms are:
- Hard or extended cranking when cold, white smoke on start-up
- Glow plug / preheating fault codes stored in the DDE (often pointing at a single cylinder)
- A "new" glow plug that still reads as open circuit or non-functional
- Rough running and misfire for the first 30-60 seconds after a cold start
- Connectors that crumble or refuse to re-latch when the old glow plugs come out
If you are replacing glow plugs or the glow plug module, replacing the harness at the same time is the sensible move - the labour is already done and a tired connector will simply take out the new plug.
Vehicle Fitment
Fits BMW models with the N57 / N57S 3.0-litre diesel engine:
| Series | Chassis | Body | Models |
|---|---|---|---|
| 3 Series | E90 LCI | Saloon | 325d, 330d, 330xd |
| 3 Series | E91 LCI | Touring | 325d, 330d, 330xd |
| 3 Series | E92 / E92 LCI | Coupe | 325d, 330d, 330xd |
| 3 Series | E93 / E93 LCI | Convertible | 325d, 330d |
| 5 Series | F10 | Saloon | 525d, 530d, 535d |
| 5 Series | F11 | Touring | 525d, 530d, 535d |
| 5 Series GT | F07 | Gran Turismo | 530d, 530dX, 535d, 535dX |
| 7 Series | F01 | Saloon | 730d |
| 7 Series | F02 | Long Wheelbase | 730Ld |
| X5 | E70 LCI | SAV | X5 30dX, X5 40dX |
| X6 | E71 | SAC | X6 30dX, X6 40dX |
Please note: this is the N57 harness only. It does not fit the earlier M57 / M57N2 engine. On M57 cars the glow plug wiring is integrated into the main engine loom and is not supplied as a separate serviceable part, which is why this listing is N57-specific.
You may be able to use this one your M57N & M57N2 however it will not be plug and play.
Not sure which engine you have? Send us your VIN or chassis number and we will confirm the correct part before you order.
What's in the Box
- 1 x Genuine BMW glow plug wiring harness, part number 12517808257
Specifications
| BMW Part Number | 12517808257 |
| Alternate Formats | 12 51 7 808 257 / 7808257 |
| Description | Wiring harness, engine, glow module |
| Engine | N57 / N57S 3.0L six-cylinder turbo diesel |
| Brand | Genuine BMW (OEM) |
| Condition | New |
| Weight | 0.24 kg |
| Drive Side | Fits both left and right hand drive models |
Installation Notes
- We recommend installation by a qualified diesel technician - the harness routes under the intake side and clips into the glow plug module from above.
- Disconnect the battery before unplugging the glow plug control module.
- Glow plugs torque to approximately 13 Nm (10 ft-lb). Do not overtighten - snapped glow plugs are an engine-out job.
- Take your time releasing the module connectors. There are clips visible from above and further clips underneath - do not force them.
- Make sure every glow plug connector audibly clicks home and each clip is seated in its bracket so the loom cannot rest on hot components.
- Clear stored glow plug fault codes after fitment and confirm preheating operation on a cold start.
Genuine BMW part supplied new. Fitment information is provided as a guide only - please confirm against your own VIN before ordering. Australian stock, ships from Melbourne.