'83 911sc Wire ID

[mdaniels]

I've been dealing with Fuse 18 blowing consistently for a while. While investigating that, I discovered that there are 3 wires on the load side of Fuse 18 (2 red wires, 1 black wire). My understanding is that there should only be 1 red, 1 black. The black wire goes to the clock. One of the red wires goes to the OXS relay. The other red wire is in a loom with one other wire that is black/red. That black/red wire is currently wired to the feed side of fuse 12.

I can't find the black/red wire near the fuse panel in the wiring diagrams I'm looking at either. The harness that they're in does appear to be factory - but I suppose anything is possible.

While trying to figure out why Fuse 18 is blowing, I measured 160ish ohms on the mystery red wire. Doesn't seem like it'd be enough to blow the fuse, but does seem like it could drain the battery over time.

So - red and black/red wire loomed together by the fuse panel, what could they be?

[mdaniels]

I have a hunch it's the alarm wiring shown in this diagram



That shows blk/red connected to fuse 7 25amp, and red is connected to fuse 2 16amp.


This shows that fuse 7 is 8amp and fuse 2 is 5amp.

What am I missing?

[mdaniels]

Unsure why the images aren't showing, but 970-13 in the bentley shows the alarm diagram I'm referring to.

[Bill Douglas]

Maybe disconnect it and see what doesn't work any more.

Could be that it's blowing at times when whatever is on the other end is activated, but fine while it's doing nothing.

[mdaniels]

I ended up disconnecting the two wires, unplugging the alarm module, and adding the required jumper. So far so good.