There is a plug under my rearview mirror base
4 wires
yellow
blue/red stripe
Yellow/green stripe
yellow/red stripe


Anyone know which is 12v switched and which is ground if any?

 

I don't have a clue, but if you know anything about wiring it should be easy for you to figure out.

1) connect the radar ground to a screw-chassis ground.
2) connect the radar positive+ to each wire (one at a time) and watch to see if it turns on/off "constantly" or "switched" with the key. There is no harm if you connect it to 2 ground wires during the testing because no voltage will flow through it.

Other than that, a $15 multimeter from walmart can tell you exact voltages and even confirm if 1 wire is a ground wire.

!!!!!Use my tech advice at your own risk!!!!!

 

I have a multi
what would it read if I had the pos on a ground wire?

And would the mirror mount screws be an acceptable ground for tester?

 

Nothing, and yes.

If you want to find the ground wire, set the DMM to check for continuity. Ground one of the leads and check wires with the other. When you have continuity, you have a ground wire.

 

well, i would assume one would read 12v after switch turns on

but there are 3 others, only one would read nothing?

is the continuity setting diff from the v setting?

 

Yes, the continuity setting is different from voltage. Continuity is the common name for resistance, which is measured in "Ohms". Use Google if you want to see the symbol for "ohms".

When checking for "continuity" of a car electrical system, usually the 2nd from smallest setting is appropriate....as there is not a grand amount of resistance in a car electrical system...you need to measuring on a small detailed scale. The test of "continuity" is actually a measurement of the resistance between 2 points.

For example, if you have 1 probe on the CHASSIS/BODY/GROUND, and you have the other probe on a wire that leads directly to ground, then you should have a resistance measurement of ALMOST zero. (you will always pick up a tiny bit of resistance just because of the physical contact of the probes to the metal surfaces...~.003ohms.

If you touch the 2 probes together firmly, you might actually get 0 ohms (no resistance). If you touch 1 probe to BODY ground and 1 probe to a POSITIVE+ wire (when there is no voltage present), you will get a solid reading of "1" which represents INFINITE total resistance...also known as "no continuity to GROUND."

After reading my last comment, I guess I realize I need to say this. If you are testing "continuity to ground" on unknown wires, make sure you disconnect the POSITIVE+ battery terminal. If you test "continuity to ground" between a ground and a hot POSITIVE+ wire with voltage present, the voltage could pass through your multimeter because you are providing a path to GROUND via the ground probe. This can fry your multimeter or shock you with 12v. bzzzzz!!

 

Ah ohms
should have remembered
Now
Say one is a ground and one is switched
What will the other 2 read? Possibly nothing?
And if so how to determine ground then?

 

Uhhhhh..............continuity has nothing at all to do with Ohms. Continuity is simply whether or not two points are connected.

Resistance is measured in Ohms.

Most DMMs will have a continuity tester, which is completely independent from resistance. If you're looking for a small reading with it set to Ohms, then when there's no continuity, you'll have a reading of 0, thus giving you an improper reading.

 

still lost ,lol

 

"Ohms" is the measure of resistance.
If you have a weak connection then your resistance will go up.
The closer you get to zero, the better the connection you have.

Continuity simply tells if you have a "decent" connection, but it doesn't tell how good that connection is.
Continuity is a quick check to see if a wire is connected, broken, or shorted to ground.

You can check the 4 wires for ground (with keys out of the ignition) with your DMM on ohm or continuity. Make sure your test leads are plugged into the appropriate connections on the DMM for testing ohms or continuity. Hook one of your test leads to a good chassis ground and then probe the wires with your other test lead. Check on ohms for a reading close to zero, If your DMM has a setting for continuity function then it will probably make an audible beep if you find a ground wire.

To check for voltage on a wire, keep the test lead connected to chassis ground. Switch your DMM to DC volts (click to see the DC volt symbol ). DMMs have different ranges. The highest voltage you are looking for is 12 or so volts. Set your DMM to the next setting higher than that voltage - on most DMMs this will be 20 volts. Make sure your test leads are plugged into the appropriate connections on the DMM for testing DC volts. Keys in, switch to ON. Probe the wires and look for voltage.

My guess is that 3 of the wires are going to give ground. Try plugging in the seatbelts and 2 of the grounds my go away.
I never had one of these seatbelt lights so I am not sure why there is a fourth wire.... maybe the lights operate when the door is open? maybe the buzzer?

Yellow is more than likely your power wire.

 

You caught me. Once again, I was sleepy and should have stayed off the keyboard. I admit I misworded a few things in that post. I was trying to explain how the terms are connected. You have worded it more correctly.

Ironically enough, I was sleepy because I have been studying "impressed current," "cathodic protection," and all the related laws of electricity...haha

 

I was basically trying to explain that continuity is the inverse (opposite) of resistance.
A resistance of 0.00 is pure continuity; and a resistance of 1.00 is NO continuity. And yes, I agree, continuity tests are not restricted to "continuity to ground" tests.

 

I'm thinking that OP is so confused because there's so much technical talk for something as simple as finding a ground and a switched 12v.

Set the DMM to continuity, ground the black lead to the chassis, find a wire with continuity (this means it is connected to the chassis, and therefore a ground).

Set the DMM to DC Volts, probably 20, ground the black lead to the chassis, pick a wire to test that shows 0 volts with the key off, turn the key on, if you get ~12v it's a switched power wire, if not, try another wire.

 

Your rearview mirror wires are for the seatbelt indicators right? I don't think you will find what you need. Better to run another harness from the fusebox up through the dash or the headliner. I know everyone has to learn, but you should find a knowledgeable friend that can help you with this wiring in person.

 

I find it hard to believe there is no switched power to those lights

 

They have power from the fuse box through the ignition.
Ground is provided by the seatbelt sensors.

 

k, heres my multi

is it set correctly for continuity?

 

yes.
if you touch the probes together, you should see what good continuity looks like.

 

.000

 

yup.

 

Not to rain on your parade, but all radar detectors are pretty much useless now a days(even the valentine v1) unless you are in heavy traffic; and lets face it, if you are in traffic, you probably aren't speeding enough to get pulled over anyway. POP mode which is basically an automated version of RF hold lets an officer detect your speed in about 0.1 seconds. Human reaction time is about 0.2 seconds. The saving grace in traffic is that it takes an officer a few seconds to zero in on your car which can give you a split second to slam on the brakes. Otherwise though, you are out of luck. Also, if you get pulled over with a radar detector, be prepared to be ticketed for every violation the officer can find.

Sources: I grew up with a few kids that are now state and local police officers so they keep me up to date on the latest in law enforcement technology.

Alternatively you can read up on what I'm briefly getting into here: http://www.radartest.com/article.asp?articleid=100622

If you actually want to beat radar detectors, you need radar jammers.

 

That may be all true, but not all cops have the latest and greatest radar. Laser is the biggie, as it's only a 3' wide beam. You only get a warning if they shoot a car near you and if it is you, it's too late.
My V1 saved me many times over the years, certain types of radar go off miles in advance. You will get stopped less, but they can still get you. That said, I try to leave early these days and not really speed.

 

It's not even about having the latest and greatest. RF hold technology has been around since the 70's and POP is almost universal. Sure there are plenty of small town cops that don't have POP, but they don't need it. Bottom line is if a cop hits you with radar you won't have time to react to your detector. If he's going for a car next to you then that's a different story, but it goes back to my point about being in traffic. If you really want to be able to beat police radar detectors every time, you need to be using a radar jammer setup or just don't don't speed excessively. Lol

Hell, sometimes I wonder if it would be cheaper to just drive as fast as you want and pay speeding tickets as opposed to spending $1600 to do a radar jammer setup.

 

under your rear view?
Those are triggered by your seatbelts.

 

lol, my v1 has saved me many times

not what this thread is about, take your soapbox to your own thread