Hardwiring Radar Detector?

i want to hardwire my cobra radar detector so it comes on when i start the car,
i realise cobra detectors are'nt the best and alot of people really hate them, but thats all i have, and it works fine for what i need it for.

i have a 2003 accord coupe,   i read how-to steps for doing the hardwiring, but most of the search results i get have to do with other brand radar detectors that use a telphone size power cord, and not the type that mine has,   mine plugs in with a plug thats at a right-angle and has a round thing that looks like the end of an A/C adapter plug, and has one of those flat power wires that has 2 sections of wire in it together.

i bought an Add-a-Fuse adapter and i bought a reel of some primary electric wire in a
gage thickness that looked like it matched the thickness of the power wire of my detector, and i bought an in-line fuse.

i understand the basics like that i would cut the power wire of the detector and then solder the new extended power wire (of the same gage thickness) to attach it to it, and then to crimp the very end of that new power wire into the Add-a-Fuse adapter and
put a fuse to handle the detector in it along with whatever fuse your replacing with the Add-a-Fuse.

my main question is: how do i find out the exact gage thickness i need to match up to the power wire of my detector ?,    cause i just took a wild guess, do i just cut the wire below the connector that goes in the detector somewhere and strip it and seperate the 2 wire sections that are inside it, and is one of them a power wire? and one a ground wire? and how would i determine which is which of them?    

any information to help me with those things would be much appreciated,    
thanks - Jonathan

Your power plug should have a fuse inside. That should give you a good indicator of what size wire to use. 20 gauge will be fine for up to 5 amps, 18 gauge for 10. Or, you could just cut the cable back anywhere you'll have plenty of room to add on and size the wire with your wire strippers.

To determine which wire is positive and which is negative, plug in the power supply and measure the output voltage with your meter. Now when you cut the cable, set your meter to ohms and test the cut ends to the output terminal. I hope this makes sense.

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My ex once told me I have a perfect face for radio.

you mean that fuse thats inside the cigarette lighter plug at the end of the power wire of the radar detector ?, cause thats the only fuse mine has?,   
i unscrewed it and took it out, its one of those cylinder shaped clear ones with metal ends, and the only thing it said on it was PF1A250V on one of the metal ends of it, but what does that mean ?,   i searched google and all i got was a bunch of stuff in japanese letters with pictures of those fuses, but how do i know what amps it is ?

i just cut the end part of the power wire off, near where the plug goes into the detector, and i seperated the two wire sections apart from each other and fit it into my wire strippers to size up the wire, and it fit in the hole that said 1.6MM, and i saw searching google that 16MM = 14gage (well, it was off a site that had to do with body piercings, but would'nt that still be the same as wire sizes?).

now, i already bought a 30 foot reel of 16 gauge wire to use, can i just use the 16 gauge wire to solder onto the detector power wire thats 14 gauge ?,   cause looking at it next to each other, its really close in size, i mean does it matter that much ?

and i bought an in-line fuse holder and fuse, cause i thought i needed one since all the hardwire kits have one in the middle of the power wire on them, and the wire size on the inline fuse wires are a different size also, like maybe 18 gauge, so would that be weird if i also soldered that in the middle of the 16 gauge wire ?     the inline fuse has a 30amp fuse in it.

Yes, that's exactly the fuse I meant. It's likely that 1A means 1 amp. If that's the case, the little conductor inside the glass tube will be super thin, almost like a hair. Wire size isn't really a concern. You can use the 16 gauge you have and it'll work just fine.

While the wire will handle much more current, the original fuse was selected to protect the detector itself. For this reason, I would keep the original fuse functional. You could still use your Add-a-fuse adapter, or you could consider just wiring in a cigarette lighter socket somewhere behind the dash (negative to ground, positive to switched ignition or accessory). Then all you have to do is extend the wires somewhere in the middle.

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My ex once told me I have a perfect face for radio.

Actually, the fuse in the power plug is there to protect the tiny gauge wire, not the radar detector.

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the12volt • Support the12volt.com

was gonna say most RD are 1-3 amps so you don't need very big wiring. Make life easy and go to auto zone or o'rileys or who ever and buy a cigg lighter socket that has a power and ground on it. wire the power to the accessory and ground the other one and plug the power plug into it..done.

https://www.bestbuy.com/site/peripheral-12v-dc-adapter-black/8294179.p?skuId=8294179&pageType=REDIRECT&issolr=1&searchRedirect=8294179

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33 years as a installer now just a retired old guy. Favorite thing to install/topic are remote starts/car alarms. Stop using test lights!!!

ok, i just wanted to make sure, thanks confirming that about the wire sizes,

i might of got some stuff confused, but i was saying that i was going to cut off that section of the detector wire that had the power plug on it, which i got that cylinder fuse out of (inside), so i would'nt be using that part anymore if i do what i was going to do, so i did'nt get when you said "the original fuse was selected to protect the detector itself. For this reason, I would keep the original fuse functional" ?    or did you think my detector had an inline type fuse in the middle somewhere along the power wire of it?, and that was where i got that fuse out of ?

the idea of wiring a cigarette lighter power socket to the accessory and ground is a good idea and much easier,    but i had too many issues with the power plug for my detector not being able to make a good contact or connection in the power outlets, and i had to turn it around or jiggle it or even put some tape around it to make it fit more snug, and thats one reason i wanted to hardwire it,   its the shape of the power plug of that detector and where the metal tabs are located on it, where it does'nt fit snug and tight, so it would probably be the same with any other cigarette lighter power socket i buy, unless i cut off the power plug and solder a better shaped one that fits better onto it ?

I meant since the wire from the plug is 14 gauge, the small value fuse was chosen by the manufacturer to protect the radar detector itself, not the wire. So if there's an internal issue, the fuse would pop preventing further damage. If it was there simply for the wire, it could be fused up to 20 amps and the internals would be toast.

What voltage comes out of the end that plugs into the detector? If it is also 12 volts, then there is no voltage conversion and you can do away with the cigarette lighter plug if you wish and just use a standard fuse. If you go this route, you want to fuse it as close to your source of power as possible. If you put your fuse somewhere in the middle, and the wire shorts somewhere before the fuse, you could possibly start a fire.

If the voltage coming out the end is other than 12 volts, then you need to make sure you feed that into the detector.

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My ex once told me I have a perfect face for radio.

14 gauge wire for a radar detector is excessive, unless it is extremely long. I'm curious if the measurement was of the sheathing and not each conductor. That would certainly make more sense. I've never seen a manufacturer use wire that big and heavy for a radar detector.

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the12volt • Support the12volt.com

geepherder, ok, i understand what you said now,    

and just so you know,   i already cut the power wire for the detector,   about 6" inches below the small plug that plugs into the detector, so the other half of that wire with the power plug is already cut off.    
then i pulled apart the two wires that make up the power wire so they are seperated and stripped the ends, then stripped the ends of two strands of extra extended wire and soldered an extended wire strand to each of the two wires coming out of the detector power wire.
i did'nt solder in the inline fuse yet, cause i was going to look in my car to see how i'm going to route the wires, so i know where to put the inline fuse so it fits wherever the wiring is routed through, but i'm glad you told me about needing to put the inline fuse somewhere close to the source of power and not right in the middle, cause i did'nt know that?

so i supposed to put the inline fuse somewhere closer to where the wire connects to the
add-a-fuse in the underdash fusebox?,    like how close are you talking about approximately?

i guess i should of tested what voltage comes out of the end of that wire first before cutting it off?,     so now since i already cut it and soldered long wires to the detector power wire, that don't connect or lead to anything yet, how would i go about testing what voltage comes out the end of it now ??

administrator,    when i measured the wire gauge size through the size holes on my wire stripper, i inserted each of the two wires that make up the detector power wire through the hole with the rubber insulation still on it, not stripped already,   and the closest fit was the hole that said 1.6MM, with a little looseness around, but it would'nt fit in the hole of the next size down, and i googled what gauge wire 1.6MM meant, and it brought up a chart on a website for body piercing, for them to know gauge size holes to pierce them with, and it said 1.6MM = 14gauge,   so i just went by that, and i assume their chart is the same as the sizes used in electrical wiring too ?

You said there was about 6 inches of wire where you cut off the plug, so you should still be able to test for voltage unless you don't have it anymore, right? Another thing to check is near the power input of the detector itself look for some polarity/voltage markings. For example, it might say "12 VDC" and have a "C" shape with a dot in the middle and a "+" connected to the dot with a line. If that's the case, it's 12 volts (direct current) and the center conductor is positive. Maybe you could search for a manual online or email Cobra if you're not sure.

Yes, I'd fuse within 3 or 4 inches of your connection.

The wire gauge is determined by the diameter of the wire inside the insulation, not the insulation itself. You can strip some back and see. It may be more like 20 or 22 gauge then, which would make more sense. 20 gauge wire can handle 5 amps, 22 gauge can handle 3 amps.

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My ex once told me I have a perfect face for radio.

i have the PDF manual for it, but it did'nt say anything about the volts it is,

but searched online and saw a real similar model on ebay, (Cobra ESD-6550), mine is a ESD-6100, but they look identical,    and theres a picture of the side of it close up and it says 12V DC,

also i saw a DC Car Adapter Cigarette Lighter Plug Charger Cord For a Cobra ESD-6100, and it said:
Input Voltage: DC 12V / Output/Voltage:12V 2A,     so i am pretty sure mine is probably 12 Volt

thanks for the info,   now i'll remember that when i size up a wire, to go by the wire inside the insulation and not with the insulation,    i did'nt know that.