My 1986 turbo wiring deviates from factory schematic
 

Car was manufactured in March of 1986 and delivered to me in May, so no one has had a chance to fool with it before me.
- A/C relay in the smuggler's box is wired backwards. 12V should be on pin 30 - mine has 12V on pin 87. No difference in performance, just a pain when trying to diagnose a bad relay.
- Round horn relay should be in 'C' position, 3rd relay from front of car. Mine is in 'B' position, where the front fog light relay should be. I had to pull the fuse panel off of the fender and unwrap the sticky insulation for relay in 'C' position to see that the wires colors did not match the schematic. Hours spent on what should have been an easy relay swap.
I'm thinking the factory beer breaks may have been a bit too frequent in March '86!

Thanks to '86 911 targa' for sharing schematics and holding my hand!

1986 Pablo Escobar was probably the root cause.

Porsche wiring itself leaves little to be desired.

yes the drawings are wrong.