I am very much a novice when it comes to wiring, but I have done two very simple installs in my Z, and I wanted to check with those who have more experience to see if everything sounds like it's the way it should be.

Note: 2004 Base Coupe

Background: I hardwired both my Sirius Audiovox SRS-IR001FM "plug-and-play" satellite/FM system (includes: display, sat radio receiver, fm switching module) and Passport radar detector a couple years ago, and just want to make sure that they way I did it is safe. I got introduced to a little bit of series versus parallel circuitry in one of my classes, so I got to thinking (and doubting myself), so that's why I'm posting up to consult the pros. I guess I'm just more concerned about a fire hazard than I am about my cheap radar detector and Sirius receiver shorting out.

My questions:

#1 Is splicing switched 12v power wires okay (as opposed to running the wire direct to the fuse box and using an add-a-fuse) as long as there is an in-line fuse installed on the accessory hot wire spliced into it? I guess I'm asking this with the assumption that the accessory component is not one that will draw a lot of power. Does the radar detector or Sirius FM tuner system draw enough power for it to be a problem?

#2 I'm assuming that the fuse associated with the switched 12v source wires, in conjunction with the in-line fuse of the actual accessory wires provide enough safety if something were to go wrong with my setup, but I'm just guessing.

Note: I've had the detector and Sirius system installed in my car for about 2 years with no problems in function of either, or the systems running off the 12v wires I tapped in to. Would I have noticed something early on if there was an issue? Like I said, I don't need any electrical fires or shorting out.

 

You are correct you should have an inline fuse for any electronic equipment. Probably fine but then again you never can be to safe especially when the total cost would be like 2 bucks!

 

Just looked at the direct-wire cord for my Escort and it already has an in-line fuse, and so does the Sirius.

 

I'm out of it with this question. Others pros would have to chime in but I have spliced to hot wires before to run all kinds of accessories with zero problems. Perhaps not the correct way to do it but as I said other electrical pros would have to answer you, Spike?

 

Hey, thanks for trying.

 

bump

 

Good question. The short answer: You’re good.

More info…

Tapping into an ACC switched hot wire (what you did) is a good way to power your radar detector or Sirius receiver. There is one caveat (which may or may not be important depending upon the device; more about this later).

Another device that you can do this way is a removable GPS unit that you “hard-wire” so you don’t have to run the device’s power-plug to your car’s power-plug receptacle. Here’s a diagram showing this setup.



You do want to keep the inline fuse in place (as you did with your Sirius receiver and radar detector) because that protects your expensive equipment from damage in case there is some sort of power spike. Of course, be sure you can access the inline fuse in case you ever need to replace this (which is unlikely). Even without the inline fuse (but you should do this, and you did), there’s no danger damaging your car’s electrical system when connecting to an ACC switched power line since the ACC lead is already fused.

Here’s the caveat that I mention earlier (and, I’m not sure it’s anything to worry about since I’ve always ignored this and I’ve never had a problem).

Some devices (I’ve only seen this with a couple of removable GPS devices) have a power-plug that is plugged into the car’s power receptacle (i.e., the “cigar lighter”), and the device’s power-plug has a step-down voltage regulator that reduces 12v direct current to something like 9.5v.

If your device has this voltage step-down implemented with its power-plug (and you discover this by looking at the device’s voltage requirement in its specification sheet), you might want to keep this power-plug inline as well. You do this by purchasing an inexpensive power receptacle (one of those $3 aftermarket power receptacles designed to go below the dashboard), and connect the device’s step-down power plug to this. Wrap the connected pieces in electrical tape or shrink wrap (you will never need to disconnect these so access isn’t important).

Since you have run your devices for two years with no problems , you can ignore this additional power-plug stuff I mention above.

Hope this helps,

--Spike

 

Spike, that right there is a great post. Maybe I'm just saying that because you're telling me that my rookie wiring is all good. But seriously, I appreciate the detail, and the clarity. Thank you!