wiring diagram questions - (radio power and "booster")

[andyt11]

I have some questions regarding the attached wiring diagram, (I'm just installing a radio). I'm sure someone more savvy with vehicle electrics will be able to help me.

1 – the green wire to the radio (top center of page) is live when the ignition is on and I i've located it. It behaves as it should when I put a meter on it. However, is this wire not protected with a fuse? It's live all the way from the ignition i think, so if it shorts at some point between there and the radio, i think it will fry. Am I reading that right? I intend to add an inline fuse just before the radio, but that wont stop the wire from frying if it rubs on something and shorts out.

2 – the “Booster” in the middle of the page – what is it? Also, does anyone know where that 16amp fuse is?

The red wire at the bottom left is fused and is a permanent live for radio memory / presets etc... I've found it and will connect it appropriately.

Any info on the green crcuit and the booster is appreciated. Thanks in advance.

[timmy2]

Welcome to the world of Porsche wiring. They did not fuse the power going to switched devices after the switch.
Thus the many threads on protecting your headlights with relay kits, installing fuses for dashboard lights, etc.
Also a reason for many melted wiring harnesses....
No idea on the booster for the radio, maybe an option under a seat?

[E Sully]

I believe it is the is the antenna booster. Fuse is probably an inline plastic fuse holder, in Luggage Compartment, below right defrost vent.
I would definitely add an inline fuse holder for the green wire to the switched radio power.

[86 911 Targa]

Hope this helps:





I rewired the radio 12V for the ignition in the "OFF" and "RUNNING" positions only.

Also, many radios have a built-in fuse at the rear of the of the unit.


Good luck,

Gerry

[andyt11]

That all helps a lot thanks everyone.

I've added an inline fuse the green wire, although I suspect it would be better if it were located nearer the ignition switch than the radio.

The booster makes sense too now, I can connect that all back up per the diagram.

I knew about the headlights - installed a relay last year to make that safe, but once you get into it it seems like there are a few un-fused circuits in the car. What on earth was Porsche thinking?!

[Richwro1]

you got the green and red correct.
Put a fuse on the green to your radio harness - some radios come with the fuse already in it
The antenna booster has a black thin wire that is wrapped around the antenna cable that plugs in the back of your radio. You will think its a ground...its not, its the power wire for the booster, which you need - ask me how I figured that out.

[andyt11]

I found the antenna booster. You are right, it's attached to the antenna cable.