Well anywhere that you can get access to the frame will work. I would suggest grounding it near the main consol* sp. There should be a few nice places in there. Make sure the surface is scratched up a bit to get a clean metal to metal connection.
well, I just attempted to do the hardwiring of my radar detector last week. I found a ground spot behind the plastic "shell" underneath the steering column. there is a bolt and washer that is part of the frame of the steering column I believe-to the right of the fuse box. I'm not sure if there is anything similar in the Lupo. I don't know if there is a repair Manual, like we have in the states, in the UK for lupos. But I have a bentley manual for mk4 golfs and jettas. hope this helps.
I'm trying to hardwire a radar detector into my 2001 Lupo GTI. I've piggybacked the first wire onto the back of my rear windscreen wiper fuse as it is connected to switched live.
I'm having problems finding a ground nut to connect the second wire to. There doesn't seem to be one in the vicinity of the fuse box. If I touch this wire against a door handle for example, the detector powers up.
Please could someone tell me the best place to make a connection to ground which is near the internal fuse box?