Glow Plug Control Unit Relay – BMW (12217801200) Diesel Relay

The glow plug control unit relay (OEM 12217801200) is a critical electrical control module for diesel-powered BMW engines, responsible for regulating the current delivered to the vehicle’s glow plugs during engine start-up. By precisely controlling the activation timing and power to each glow plug, this control unit helps ensure efficient cylinder pre-heating, smoother cold starts, and reduced emissions, especially in colder conditions. A faulty glow plug relay can result in hard starting, extended crank time, excessive exhaust smoke, or glow plug warning lights, making timely replacement essential for reliable diesel engine performance and start-up behaviour.

OEM Number: 12217786821, 12217801200, 12237786869, H7285681, 132302, 0884030, 75614324, GSE101

Operating Mode : 12V

4 CYLINDER MODELS ONLY!

Quantity : 1

For the Following Cars :

Alpina D3 (E90) 2.0 Saloon 12.2005-04.2008
Alpina D3 (E91) 2.0 Estate 12.2005-04.2008
BMW 1 (E87) 118 d Hatchback 06.2004-02.2007
BMW 1 (E87) 120 d Hatchback 06.2004-06.2011
BMW 3 (E46) 318 d Saloon 09.2001-03.2003
BMW 3 (E46) 320 d Saloon 09.2001-05.2005
BMW 3 (E90) 318 d Saloon 03.2005-08.2007
BMW 3 (E90) 320 d Saloon 12.2004-09.2007
BMW 3 Compact (E46) 318 td Hatchback 03.2003-02.2005
BMW 3 (E46) 320 Cd Convertible 02.2005-12.2007
BMW 3 (E46) 320 Cd Coupe 11.2003-07.2006
BMW 3 Touring (E46) 318 d Estate 03.2003-02.2005
BMW 3 Touring (E46) 320 d Estate 09.2001-02.2005
BMW 3 Touring (E91) 318 d Estate 09.2005-08.2007
BMW 3 Touring (E91) 320 d Estate 12.2004-08.2007
BMW 5 (E60) 520 d Saloon 09.2005-02.2007
BMW 5 Touring (E61) 520 d Estate 04.2005-05.2010
BMW X3 (E83) 2.0 d SUV 09.2004-08.2007 

All our Glow Plug Control Unit Relay For BMW 12217801200 are OEM quality and reliable after market car parts. This Glow Plug Control Unit Relay For BMW 12217801200 is specifically compatible with Alpina D3, BMW 1, 3, 5 & X3.

Please use our make-model-year tool to check this part's compatibility with your vehicle. However, please note that our tool is for reference only and we recommend that you check the part number on your old unit prior to purchasing.

If you are still not sure about the compatibility of this part to your vehicle, please supply us with the VIN number or Reg number in our live chat or contact form! You can also find details on our purchasing & shipping guide here.

Key Benefits

Regulates Glow Plug Current with Precision
This control unit manages the electrical current supplied to the glow plugs, ensuring they heat consistently at each ignition cycle for effective cold starting and combustion.

Direct Replacement for OEM 12217801200
Manufactured to match the original equipment specifications, this relay installs directly in place of the factory unit with no modifications required, maintaining correct electrical and engine control integration.

Improves Cold Start Reliability
By ensuring the glow plugs receive the correct power and timing, this unit helps reduce difficult starts, especially in cold weather, lower crank times, and decreases visible white smoke at start-up.

Supports Engine Performance and Emissions
Accurate glow plug control contributes to complete combustion right from start-up, helping reduce unburnt fuel emissions, improve fuel economy, and maintain optimal engine performance.

Wide BMW Model Compatibility
Compatible with a variety of BMW 1, 3, 5, 6, 7 Series and X-Series diesel models that use part number 12217801200 or equivalent references, ensuring broad applicability across popular diesel engines.

Frequently Asked Questions (FAQs)

Q: What does a glow plug control unit relay do?
A glow plug control relay regulates the electric current to the glow plugs based on signals from the engine control unit (ECU), allowing the glow plugs to pre-heat each combustion chamber properly prior to engine start-up. This improves start-up performance and reduces engine wear.

Q: What are the symptoms of a failing glow plug relay?
Common symptoms include difficulty starting the engine in cold conditions, extended crank time, illumination of the glow plug warning light, rough idle shortly after starting, and increased white smoke from the exhaust. 

Q: Which BMW models use part number 12217801200?
This glow plug control relay fits various diesel-powered BMW models — including many 1, 3, 5, 6, and 7 Series, as well as X3/X5 vehicles — that specify 12217801200 for their glow plug system control. Always verify compatibility with your VIN or existing part number before ordering. 

Q: Is this part a direct replacement?
Yes. This control unit is a direct replacement for the original glow plug relay with OEM number 12217801200, designed to match the factory electrical and mounting specifications.

Q: Do I need professional installation?
Installation requires access to the engine’s glow plug wiring harness and relay location. While experienced DIYers may complete the replacement, professional installation is recommended to ensure correct connections and avoid potential ECU fault codes.