Dal is correct, yellow wire is for oil level sending unit. Surprising that you do not have a warning light on the dash if that wire is disconnected.....

NO LOCTITE...... the PO's of both of my 944's thought like the poster above, and I have had one hell of a time removing many bolts on my engine.

Places where loctite is okay:
CV bolts - If you do not use new/dry bolts every single time they are out, they have a tendency to work loose. Use blue loctite here if you want
Allen head screw for the ignition rotor - I only use blue here, but it is a good idea to help keep it from backing out
Steering rack bolts - I had a couple back out on me once, and now I use blue loctite on these

I can't think of any others off of the top of my head. IMO antisieze should be used with discretion. It should not be used on lug nuts, crossmember bolts, or anything else that is 'mission critical'. That said, I used it on the allen head bolts that help hold the head down (around the coolant passage), and basically anywhere else that when I removed the hardware I found it to be excessively hard to remove, or found badly corroded threads.