Please help me identify this mystery harness

[e39krazy]

1974 2002

Before you roast me, I have looked over the diagram many times. These crunchy brown wrapped wires have me stumped.  Tested wires and have no clue where these are supposed to go.  They go into a relay and when I unplug this relay nothing seems to change. At this point I'm starting to wonder if its for old emissions that's no longer there.  Its not wiring for the washer pump as ive already found and tested that in the passenger fender area.

 

[Mike Self]

It's most likely a completely separate harness, and contains the wiring for all the emissions stuff required on US-bound cars by the EPA.  Looks like a PO removed all the hardware (vacuum switches, throttle positioner etc) but left the wiring.  IIRC it can be unplugged from the car's main wiring harness at one or two places and you'll be done with it.  Even in CA they don't do emission inspections on pre 1976 cars...

 

mike

[2002iii]

The silver box about the size of a cigarette pack on the firewall is for smog. The relay next to it is probably smog too. If you don't have to pass smog  you can remove all the smog stuff and cut the harness off from the main harness, except the green power wire to the coil.

 

Solid brown wires are almost always grounds.

Edited March 5, 2023 by 2002iii

[Dudeland]

My smog harness was blue.  Not sure what that is. I haven't had my coffee, I am not seeing an electric choke/solenoid wire?. 

 

 

[Dudeland]

Where is the temp sensor wire? 

 

[e39krazy]

12 minutes ago, Dudeland said:

Where is the temp sensor wire? 

 

Temp sensor wasn't plugged in at this point, was in the harness with the starter wires and such.  No clue where the choke wire is, going to be running a new one for the weber.  Ive been looking through photos of 74s on bring a trailer for reference and I just cant tell.  

Edited March 5, 2023 by e39krazy

[e39krazy]

15 minutes ago, Dudeland said:

Where is the temp sensor wire? 

 

1974 BMW 2002 4-Speed

BRINGATRAILER.COM

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Bid for the chance to own a 1974 BMW 2002 4-Speed at auction with Bring a Trailer, the home of the best vintage and classic cars online. Lot #92,775.

 Like in this car here, that harness seems to be plugged into the water choke, car still has all emissions and seems like the harness is also plugged into a sensor in the back of the intake 

 

[Conserv]

1 hour ago, Dudeland said:

 

… My smog harness was blue…

 

The blue conduit for the emissions wiring might be a 1975-76 thing — and perhaps not a 1974 thing. Was yours possibly a ‘75 or ‘76?
 

Best regards,

 

Steve

 

[e39krazy]

Just now, Conserv said:

The blue conduit for the emissions wiring might be a 1975-76 thing — and perhaps not a 1974 thing. Was yours possibly  a ‘75 or ‘76?
 

Best regards,

 

Steve

 

Mine is a 74 

[Conserv]

3 hours ago, e39krazy said:

Mine is a 74 

Sorry. I was asking @Dudeland if his car was a ‘75 or ‘76.

 

I’m not certain when the blue conduit began — your car obviously has brown conduit.

 

The blue conduits, which are certainly on U.S. 1975-76 models, contained the emissions controls harness, plus… an “ohm-adjusting” power lead for the distributor.

Below, my ‘76. And it used the same blue conduit, albeit a larger diameter version, for the spark plug wires. All the blue conduit shown is original to my ‘76.

 

Regards,

 

Steven

 

[2002iii]

My 1974 had the same same tan color wire sheathing as the OP's.

[John76]

Those brown wires may be the grounds for the White and Red electrovalves found on the '74s.

Here is the smog map for the '75 and '76 CA cars. Your '74 does not have the air pump or the Black electrovalve.

I did not include the Brown wires to the valves...just the hots.

Look  for a Green/white wire in all your harness nest. This is the switched +12V fuse-protected line for the electric choke, and idle cut-off solenoid, etc.

 

 

 

[Dudeland]

6 hours ago, Conserv said:

Sorry. I was asking @Dudeland if his car was a ‘75 or ‘76.

 

I’m not certain when the blue conduit began — your car obviously has brown conduit.

 

The blue conduits, which are certainly on U.S. 1975-76 models, contained the emissions controls harness, plus… an “ohm-adjusting” power lead for the distributor.

Below, my ‘76. And it used the same blue conduit, albeit a larger diameter version, for the spark plug wires. All the blue conduit shown is original to my ‘76.

 

Regards,

 

Steven

 

Just catching up, yes it is a smog 75.

 

[Dudeland]

6 hours ago, Conserv said:

The blue conduit for the emissions wiring might be a 1975-76 thing — and perhaps not a 1974 thing. Was yours possibly a ‘75 or ‘76?
 

Best regards,

 

Steve

 

Yes a 75

[Dudeland]

On 3/4/2023 at 3:05 PM, e39krazy said:

 

 

The wire with the green/yellow tape on it at the bottom of the picture.   I think I see a K(maybe choke).  It appears to be a green and white wire.