Rev counter drops to zero and clock display goes off when I switch on my headlights.....

So I found a picture of an MFA stalk and compared the wiring and concluded it must be the connector I posted above. Earthed the red/white with ignition on, on the car side, but nothing happened 🤷🏻‍♂️ 
So where do I go from here? Does the Rollmode (switching the MFA) pin 8 on the main cluster have anything to do with it? 
Can I check any of the wires for continuity to narrow it down?
Are there any fuses / relays to check additionally?
Thanks! 

Also wondered if it's normal that I'm not seeing the little black arrow pointing down from the clock icon above the MFA? So it's almost like it's not even recognising the clock as part of the MFA function. 

Unplugged fuse 3 for a minute to see if a reset would change anything but it didn't. 

Also: is it normal for this area to get really hot when the ignition is on?

Yes that's the stalk plug, the one on the right is the car side. So earthing the red/white there breifly should cycle thru the MFA modes, if not cluster fault or a break in the red/white wire somewhere between the plug and cluster pin 8, squashed pin in cluster plug or damaged blue foil.

If you put a jumper wire in the back of the clock plug between 2 and 8 with ignition on the mode should cycle. If it still doesn't the wire is ok, look at the pin and the cluster.

The clock icon on MFA doesn't mean time, it means how long the current trip is, or on mode 2 how long the clocks have been powered up in total.

Those resistors are probably on ignition circuit so will constantly have power, if so you would expect them to get hot. Hard to say for sure without circuit tacing the entire blue foil to work out what they are for.

So the cluster is now working perfectly except for the MFA is that right? If so and all the cluster.pins are deffo good you may need to send them off for repair

Thanks John.

Here's what I've tested with ignition on:

- earth the red/white mode wire car side: nothing
- ran new earth to car side brown just in case: nothing
- continuity of the black and red/white on car side connector to the two pin connector on the back of the clocks: fine 
- ran wire from pin 2 to pin 8 on main cluster connector to check if it would cycle through: nothing

I guess the only thing I haven't checked yet is the continuity from the MFA connector car side to pin 8 and the pin itself. 

I've had to put the dash back on temporarily but I reckon it'll be off again before long. The pins on pin 2 inside the connector were bent upwards and I suspect it's a matter of time before my bending them back will lose its effect and I'll be back to dodgy earth connections. 

Longer-term: do you know anyone who fixes these clocks? I don't really want to just buy a different one - I like the low mileage on mine

Thanks,
Ben 

this guy:
https://www.clubgti.com/forums/index.php?threads/motometer-cluster-mfa-repair-fix-found.288785/

Thank you. I'll drop him a message. The thought of putting such a fragile thing in the post slightly scares me 😂

rubjonny

What are the odds that whatever is causing the MFA not to work is also setting my low oil pressure warning (buzzer and light) off intermittently despite oil level and pressure being good? 

I've done the wire removal tests for both pressure switches and they're behaving as they should. 

Thanks 

The Oil pressure Buzzer/light are controlled by a "L" shaped board, that is located in the speedometer housing at the rear.

So If you have a good Voltage there and a good ground, unless the board went CA-Ca, you should be okay, but I have been seeing lately that the board tends to go flaky.

MFA isn't working. Earlier on I got the buzzer noise continuously on, whilst previously it was just an intermittent buzz when it sounded along with the lights flashing. 

if you still get the buzzer with the blue high pressure switch wire earthed then either the board has gone or you have (another) wire fault