Yotatoy -
Thanks for the info.
I am still seeing inconsistencies. I think that some of them may be due to different ways of achieving the same result. This is where schematic diagrams would remove all doubt. Describing wiring connections verbally is not the best way to go. If wiring is described verbally, it should be for only one clearly identified vehicle and both wire color codes and pin connections should be listed for every connection.
I'm going to assume that the following wiring diagram is correct and see where it leads. This wiring diagram makes the most sense to me. There is no socket at ECU pin 66 currently (in my formerly automatic transmission 2002 Golf TDI), so I will need to add a wire to that location and route it down to the blue/black clutch relay location under the dash:
I got a 2001 manual Golf TDI harness from the junkyard and pulled the socket and wire from ECU connector pin 66 on it (it is white with a red stripe, btw). I will insert it into the ECU connector in my 2002 Golf and figure out how to route it to the 175 relay (which will later be replaced by a 53 relay).
I am not going to mess with moving the socket on pin19 in the ECU connector to the pin 66 location, as is instructed in other posts. I may use some wires in the TCU harness to help route the newly added pin 66 in the ECU connector down to the clutch relay location under the dash, but I don't think any TCU harness connections are necessary and it adds confusion, if that isn't explicitly stated.
I have had to undo connections that I made previously that didn't work at all. The 175 relay seems to be the issue with those approaches. If the electronics within the relay isn't gutted, and the relay is re-wired internally to be only two standard relays, I don't think any of the approaches leaving in the 175 relay can work. The 53 relay is just a single relay with no extra electronics inside.
The second relay (of the 175 relay) is not required, since the reverse light switch on the manual transmission can directly handle the current to the backup lights (as can be seen in the wiring diagram above).
The clutch starter lockout is already mostly wired (pins 2, 6 & 8 on the 53 relay) - you just need to add the white/grey clutch switch connection to ground (on relay pin 4), to prevent the starter from being allowed to crank, when the clutch pedal is not pressed down.
Thanks.
I will post later to say whether it worked or not. So far the wiring part of the job has been a nightmare to figure out. If the above wiring diagram is correct, it won't be a big deal to wire up.