I want to hard-wire my radar detector to the under dash fuse box(preferably) or splice into a 12v hot wire(w/key on). I tried using a circuit tap into an existing fuse but cannot get it to work. I'm sure the ground is good, the only thing I can figure is the tap is bad. It's not like I haven't done this before but this one has me stumped.

Can anyone give me instructions on how to make use of one of the "unused" fuse locations in the fusebox or point me in the direction of an easily accessible wire that I can tap into.

I don't really want to go out to the battery if I dont have to. I'd also like it to only be hot with the key on.

I also had a brain fart on my coffee break, I want to mount the radar detector high on the windshield above the rearview mirror, could I wire it to the dome light and is there a good groung location on the domelight(Yes, I know this location will be hot all the time, that's OK if it will be easy to wire).

Any help would be appreciated.

Hobbit

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99 XLT,4.6L Auto,4X4,tow pkge,Factory Side Steps and Mudflaps, K&N filter,BugflectorII, Amazon Green/Silver, Pace Edwards Rolltop Cover, still want a Superchip and by golly I'm gonna get one (just as soon and I hit the lottery )

 

Come on stereo installers or anybody. Somebody should be able to come up with some help. How about it?

Hobbit


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99 XLT,4.6L Auto,4X4,tow pkge,Factory Side Steps and Mudflaps, K&N filter,BugflectorII, Amazon Green/Silver, Pace Edwards Rolltop Cover, still want a Superchip and by golly I'm gonna get one (just as soon and I hit the lottery )

 

I just wrapped the positive wire around one side of one of the fuses (for the exact same install). Didn't use a circuit tap or anything like that. It works fine! PS: Test the ground (if you haven't) there's a lot of plastic under there to fool ya.

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'97 F-150 Lariat Ext. Cab 4X4

• White/Silver
• 4.6L, Auto.
• Tinted Windows/Bedmat/Toolbox/Lund Bug Deflector
• 265/75/16 BFGoodrich on polished 16x8 AR-136's
• Cat-back Dual Exhaust
• Polar Bear Grille Guard

 

The bundle of wires going into the steering column has about any kind of hot wire you could want. Hot all the time, only when switch in on pos, or when switch is in acc or on position. Just buy a cheep meter to check the wires. It is recommended not to use a test light when doing this kind of checking on newer vehicles for stereo, alarm or other instalations. The reason being that the current used to light up the test light could cause the air bag to deploy if you tried it with the wrong wire under the dash.

Just make sure you use a small inline fuse (probably 3 to 5 amps). The larger wires should also be connected to 20 to 30 amp fuse so you shouldn't increase the possibility of overloading the fuse for whatever wire you tap into.

I would also recomment soldering the connections and using shrink wrap tubing.

 

Radar detectors are a snap. I do them all the time. I recommend using the windshield wiper fuse, it only turns on with the key and doesn't have a critical components on the circuit. Also, use a 1 amp inline fuse for a radar detector, as close to the power your tap into ( the wiper fuse) as possible. Any more than 1 amp and if you do ever have a short it will smoke the radar before the fuse will blow.

With the way these new fuse blocks are, I don't use a fuse tap. Fuse taps have a tendency to spread out the contacts in the fuse block. I just strip the wire, slide it straight into the hot side of the fuse (where the power comes into the fuse block before going through the fuse) that was removed, and replace the fuse. Don't spin the stripped wire tight either, that is defeating the purpose and will spread the contacts in the fuse block. Just have patience and be sure all the strands go into the hole and don't stray out to the other side. Doing it this way will allow the fuse to move the individual strands of wire when you stick it back in so it doesn't open up the contacts of the fuse block.

If the wire is real thick, cut half the strands off before putting it in.

As for a ground, I always go straight to the body, usually behind the driver kick panel. Just crimp on a ring terminal and use a drill point screw to connect it. A lot of times I see people connect ground to screws for the dash and/or dash supports. NOT GOOD! These can be very bad ground points and drive you nuts. Just take the time and ground directly to the body with your own screw.

Mounting it above your mirror is perfect. Just extend your wire, run it above the front edge of the head liner, down behind the driver side pillar moulding to the fuse box and connect as I described above. Don't waste your time with the dome light, unless you want your radar detector to go on and off when you open and close the door, and only work with the dome light on.

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Boss™

Just Ordered 2001 F-150 Lariat, Oxford White/Silver 4x4, medium graphite leather, SC, SB, SS, 99L 5.4L, 44E tran, 7700# payload, Class III Tow, 3.73LS, Skids, Capts chairs, 4W disc ABS, shift-on-fly, keyless, HD everything
Planned Mods:
"Protected by Smith&Wesson" sticker, Westin Chromed Stainless Nerf Bars, ARE LS II bed cover, Bedrug™, Gibson Swept Side Cat Back, K&N filter w/airbox mods, headers, Superchip, 3" body lift with at least 33's, alarm/pager/auto start system, stereo system




[This message has been edited by Boss96Hog (edited 08-24-2000).]

 

Thanks for the responses guys, wanted to stay away from inserting the wire into the fusebox that way. In my old age I'd like to try to make a more professional looking installation. It's cleaner and neater and is less likely to damage the electrical system. I actually pulled the dome light assembly and this could be a good location for what I want to do. When you pull the clear lens off you will see three mounting screws. Undo these and the base comes off. Two of the screws have power/ground wires connected to them that the screws screw into. This is hot all the time and the power is distributed to the map lights through the base. (This is hard to describe but will become clear if you take it apart). Only the dome light is switched to the doors the maplights are hot all the time. All's I need to do is add ring conectors, an inline fuse and run the wires inside the headliner to the windshield.
This is one way to do it, but, after talking with a couple of different stereo installers I'm thinking about running a hot wire through the firewall to a fused distribution box (cause I may want to run a few more accessories later) and wire it from there.
Thanks for the help

Hobbit

 

HOBBIT,

The way I described is very professional looking and will do no damage to anything. I've been doing this for almost 20 years, with no problems. Actually, just sticking the wire in the fuse socket as I described looks much cleaner than a fuse tap.

Remember, you are hooking up a radar detector that draws maybe 300ma. There is no need to run out to the battery, that is insane. Your stereo guys are very correct if you were running power to an amp or somthing with a high draw. But for a radar detector, do yourself a huge favor and listen to me!

 

I hear O learned one!
2 questions:

1 which side of the fuse is hot going in? Left slot or right?
And 2. Will a self tapping screw drilled into the fire wall or the interior body somewhere around the parking break pedal mount suffice as a ground. Do I need to sand some paint off under the screw? There is a nice big bolt that holds the bottom of the parking brake mount to the side of the truck, I was going to use that as my ground. I already tried testing the fuse slots and that bolt with a voltage tester but was getting no reading with both key on and off. Thats why I was getting disgusted and planning to go out to the battery. THAT I know how to do.

Thanks for you help

Hobbit

Electrically challenged.

 

The side of the fuse that is hot differs from car to car and I'm not sure right off the top of my head which side it is. The only way to find it is to use a meter. If you use the wiper fuse, it will only be hot with the key ON, not ACC. Just start the truck and test it with the truck running if your not sure about where ON and ACC differ on your ignition switch.

I always use a drill point screw for ground on the side of the body behind the kick panel. I don't like using bolts already there unless it is a factory ground wire stud bolt. I never liked going into the fire wall for 2 reasons. 1. It's hard to be sure what is on the other side of the firewall where you are installing the screw. 2. It makes a hole to the outside of your truck. Behind the kickpanel is thicker metal and doesn't make a hole that goes outside the body.

You don't need to worry about taking the paint off, the screw will take enough off as you put it in.

 

Boss is right, the radar detector is such a low current draw that you definitely don't need to run a wire and distribution block from the battery.

Both sided of the fuse is actually hot. Just that one side is before the fuse and one is after the fuse. It is better to be on the before end if possible. But then again with a radar detectors minimal amp draw it really doesn't make that much of a differernce.

 

Just an update.
I still wasn't getting a reading with a multimeter in the fusebox. all's I could think was I wasn't able to get actual contact with any metal tab in one of the slots. I also tried to insert a wire along one of the fuses "paddles" and a screw into the kick panel and guess what? No power! I don't know what is going on.

So, I went ahead with the dome light idea. Ran an electricians fish tape through the headliner from the domelight to the windshield. ran the ends(fused hot and ground) through a small hole already in the light base. Put ring connectors on the ends with a little elec tape. tighten down the appropriate screws with ring connectors attached and BINGO we got power! Put everything back together and we're good to go.
I appreciate all the help offered, I'm not sure why I couldn't get things to work at the fuse box, but that's a problem for another day.

Thanks again!

Hobbit

 

If you can't get anything into the fuse slot to check which side is hot before the fuse, here is a tip. Get a blown fuse of any amperage, and replace the fuse you are trying to test with the blown one. There are two metal tabs that stick out of the plastic on the fuse. Whichever side of the blown fuse is hot when you test those metal tabs with a meter is the hot side of the fuse location before it goes through the fuse.