My own MPI engine’d SPI Automatic has a neutral switch as I described. I used this to trigger the daytime running lamps. This is not the identical switch, however the automatic saw a bit of evolution during the nineties as they brought the 1300 engines and the park feature into the mini. The switch looks verisimilar to the remote/sandwich mount gearbox reverse switch that has recently been sought after. The wire colours do not deteriorate and so you could easily identify them and a relevant wiring diagram would confirm their purpose.

There is an SPI only switch that goes on the throttle pedal stop inside the car. It could have lost its home with the pedal change from auto to manual. My guess is it’s to cut off the ac compressor at wot for more go power. The one sold now does not look the same though. Part # NNS10001 on a short pigtail.

I was looking around my car and haven't found anything that matches yet.  My car also has a few random connectors with nothing in them  (always assumed maybe fog harness?)

Possibly the Cut Out to stop the original Auto from starting in gear?  Just connect the2 wires.

On the gearbox piece have you tried disconnecting the wires or seeing if any had power to them? I think Mur has the right answer.

The temp gauge should read just below the middle range on the gauge and the fan usually kicks on when it rises above the middle mark.

thank you.

I'll poke around my SPI AC auto and see if I can find something like that.  From your last picture it looks like the electrical connection is on the left behind and above the oil filter?  My AC condenser is right there so I have limited visibility back there.

jimmysaig. I have complete SPI ECU unit. throttle body for sale.. best offer. came off running mini last month.. I think it is best to just to convert to carbs with SPIs these days.. you seem to NEVER can fix all the gremlins. in that new SPI throttle bodys are NOT sale any more like the new MPIs one from www.burlen.co.uk later bc

What does the temp gauge in the car do?    Does it act 'normal"

Just thinking out loud here= NO REAL evidence.  Internet Diagnosis.

 Thought =Temp Sensor -  If it has failed. it could fail and make the computer think its running HOT.   Running HOT COULD be forecing the fan relay on and run the fan to COOL it down. also Could mess with the 'fueling' and Computer be adding MORE fuel = Richer mixture also to 'cool it down.

 All 100% Speculation

Tempurature sensor is in the bottom of the intake manifold = UNDER IT = like a bugger to access and Impossible to replace by not removing the intake for acceess.

You need to make sure the fuel trap is clear. When SPI's run rough/rich the fuel trap sometimes becomes contaminated and blocked so it blocks the vacuum signal. It is located on the firewall with two vacuum lines going to it make sure you connect them back correctly.
Even if the vacuum elbows look good just replace them if original they are quite old now and usually fall apart in your hands, there are around 8 of them.

The fan problem is strange but start by replacing the sender along with the seal and clip at the bottom of the radiator.

You need to clear any stored codes from rough running, they do not clear by removing the battery terminal you need a Rover code reader to do this.

Some updates:

I found a disconnected vacuum line and reconnected it, but the issue persists.

To add the electric fan comes on as soon as the car reaches operating temperature and does not turn off. I can even turn the car off and leave it overnight and the fan will still come on as soon as you turn the key.

However, if the car sits for several days, then the fan only comes on after reaching operating temp.

Thanks for the help!

Absolutely nothing to do with the fuel injection.
Disconnect the switch from the wires or join the two wires together and see if it affects the starting.

Injected automatics have a neutral switch fitted to the front plate of the gearbox, as opposed to earlier cars that had a neutral and back up lights switch at the shifter.

I swapped my 89 carb'd Jap spec MINI from auto to manual.  That switch is definitely related to the FI as I do not have that

great info!!! Thanks so much!!!!

The guy I bought the car from, we've been friends since before he even bought the car about 15 years ago. He did the auto to manual conversion himself and he couldn't remember what that switch was. Now I guess its possible he didn't remember? 

But you're explanation makes a lot of sense and I will try it this weekend. Many thanks.

Thats a  ' mechanical' switch of sorts. The hard "ball ' on the end is designed to come in contact with 'something' else hard  to ' activate the switch manually.
 
I know very little about automatics. and I once owned a normal SPI (no AC, Manual) and never saw a 'switch' like that.

I would safely bet it has nothing to do with your hard start issue'   more of a 'leftover switch' to the old auto.

I would consider un plugging.. and seeing how the car acts. 
      Then - you could Jumper the wires  in the plug and see how the car acts.
  I wonder if its sort of a ' neutral park switch= that goes with the auto.  It COULD disable to car if activated.. Like = hey = its not in park == DONT start  switch.
 
You could find the car run at all with this disconnected.. But if you hard wire it together== remove the switch you're done.

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If this is still an SPI = ECU running mini ..  Hard starts when warm = CHECK the Vacc lines from the intake manifold= to the fuel trap = to the ECU.

 Regular problem..  and temp will affect more == cracked fittings = when cold are OK = when warm they open up= air leaks by and causes vacc leak signal to the ECU = Hard to start signal =  Start with that.

I've looked everywhere around the block on the front side of the engine! used mirrors etc. I really don't want to have to start taking stuff apart cause right now I dont have the time.

Do add a little more info, I'm having an issue where the car starts up fine when cold, but after it warms up its really difficult to crank up, appears to be starved of fuel. Not knowing what this sensor is, Im wondering if its related.

Odd that's it up front....otherwise I would have guessed something to do with idle or kick down on the automatic

Yes....it has. Original was auto now its a manual.

Looks like that part but they stopped using the back up light switch on the transmission years before the SPI was introduced.
The reverse light switch is located on the rod change housing.
Has this SPI been converted from Auto to manual?