MFA problem

Hi , Stupidly it would seem , decided to up grade / replace instrument cluster bulbs with LEDs (old ones dead or v dim)
followed the how to guide , tilted the binnacle forward enough to fit bulbs but did not illuminate when headlights were switched on .
decided to refit in the hope of it working ,no joy . But then  saw the MFA screen was on but with all segments filled .(was fully working before)
how do i fix this ?
Someone at a show today said possibly a bad earth ??
Or has my stupidity cost me big ££££
Surgestions on a post card please!

LED lights are polarized as in they can only be fitted one way.  So if they didn't turn on, then remove and reinsert 180 out.

Same with the MFA i suspect that you got some wires pinched.  

The Ground for the mfa is really from the
Right rear (as you look at the engine) valve cover corner to the Coil Bracket bolt.

If you want a good ground, then remove the cluster, and Drill a 1/8 hole on the inner firewall, sand down to bare metal about 1/4 of an inch around the hole.

Using a ring connector and about a foot of wire attach the wire to the ring connector and crimp.  The Screw the ring connector to the firewall with a sheet metal screw.  The other end of the wire goes to the wire side of your main cluster connectors brown wire with a 3m Scotch-lok wire splice.






From:
https://www.volkswagenownersclub.com/threads/improving-your-cluster-connections-and-ground.24949/?post_id=753377#post-753377