BMW E21 Harnesses

E21 Chassis Years and Models included (But not limited to):  

• 75-83    320i, 323i

The original engines from the chassis listed above include the M10 and M20

*If you are planning on using an automatic transmission, please send us a message.

LIFETIME Warranty with all harnesses!

This warranty only extends to the original purchaser and is limited to workmanship only. If you have any problem with these, just send us a message and we will take care of it.

We provide harness adapters for all of the following engines:

• M50
• S50 (US and Euro)
• M52 (Single vanos)
• S52
• M52TU (Double Vanos)
• M54
• S54 (US and Euro)
• M60 or M62 (obd1)
• M62 (Bosch ME5.2) 1 single ECU Plug
• M62 (Bosch ME5.2.1) 5 small ECU Plugs
• M62TU (obd2)
• S62

We have our own complete diagrams for each of these motors and chassis. For the newer M52TU, M54, S54, M62TU, and S62, we used the E39 and E46 ETM. Therefore the E46 or E39 harness is desired. The standard E46 harness is capable of reaching the original ECU location in the glovebox. A weblink will be provided on the instruction sheet to assist you and possibly make it work the same for the E21.

All fuses and relays are included with all harnesses. With an exception of the USA Timed EKP modul fuel pump relay for the S54 and S62 harness.

All harnesses have been measured out for LHD vehicles and placing the DME in the glovebox compartment.

RHD is available upon request.

Detailed instructions are included with all harnesses

EWS must be deleted.

We now offer the M52TU, M54 (B22, B25, and B30), S54, and S62 EWS deletes (Free, with a purchase of an adapter harness). Just send us your ECU to be modified.

**$70 value without a purchase of a harness.  

We will assist as much as we can throughout your entire engine swap.

These can all be customized to order. Please let us know if you have any special requests.

M50/S50/M52/S52 obd1 for E21

These adapters include the following:

• Cluster temperature wiring  
• Fuel pump wiring
• Oil pressure wiring
• Alternator wiring (Battery Charge light)
• Tachometer wiring

• OPTIONAL: Check Engine Light wiring with bulb

M52/S52 obd2 for E21

These adapters include the following:

• Cluster temperature wiring  
• Fuel pump wiring
• Oil pressure wiring
• Alternator wiring (Battery Charge light)
• Tachometer wiring

• OPTIONAL: Check Engine Light wiring with bulb

M52TU for E21

**Must use with MS42 DME

These adapters include the following:

• Cluster temperature connector
• OBD2 diagnostic port
• Fuel pump wiring and relay

• OPTIONAL: Secondary Air Pump relay and connector

M54 for E21  

**Must use with MS43 DME 

These adapters include the following:

• Cluster temperature connector
• OBD2 diagnostic port
• Fuel pump wiring and relay
• Electronic accelerator pedal connector

• OPTIONAL: Secondary Air Pump relay and connector

S54 for E21

 **Must use with MSS54 or MSS54HP DME

Please let us know which engine harness and transmission harness you plan on using.

**The USA version will require the Timed EKP modul fuel pump relay BMW Part# 61357892976. This relay is not included.

These adapters include the following:

• Cluster temperature connector
• OBD2 diagnostic port
• Fuel pump wiring
• Electronic accelerator pedal connector
• Momentary switch for Sport Mode

• OPTIONAL: Secondary Air Pump relay and connector

S62 for E21

**Must use with MSS52 DME  

**The USA version will require the Timed EKP modul fuel pump relay BMW Part# 61357892976. This relay is not included.

Best used with the E39/M5 engine harness.

These adapters include the following:

• Cluster temperature connector
• OBD2 diagnostic port
• Fuel pump wiring
• Electronic accelerator pedal connector
• Momentary switch for Sport Mode

• OPTIONAL: Secondary Air Pump relay and connector  

M62TU obd2 for E21

Best used with the E39 engine harness.

These adapters include the following:

• Cluster temperature connector
• OBD2 diagnostic port
• Fuel pump wiring and relay
• Electronic accelerator pedal connector

• OPTIONAL: Secondary Air Pump relay and connector

M62 for E21

Best used with the E39 engine harness. 

**PRE-97: Intended to be used with the "474" ECU (Bosch ME5.2) (1 Single ECU Plug)

**POST-97: Intended to be used with the "DME 1" ECU (Bosch ME5.2.1) (5 ECU Plugs)  

 These adapters include the following:

• Cluster temperature connector
• OBD2 diagnostic port
• Fuel pump wiring and relay

M60/M62 obd1 for E21

*Intended to be used with an E34 M60 engine harness with the round X20 connector.

These adapters include the following:

• Rectangular "c101" Chassis Connector
•  X20 Engine Connector
• Cluster temperature wiring

• OPTIONAL: Check Engine Light wiring with bulb