power antenna wiring question *

[TurDz]

Copied and pasted from the 240sx tech forum:--Last night, my mast got jammed and basically the antenna broke. The motor is fine but it was loud in the first place and I'd like to replace the whole assembly.

My car (according to the previous owner) originally had a fixed mast antenna, but was swapped out with an aftermarket one.. It had the letters (MAS) on it, part#PA222. It seemed like a generic piece to me.

I spent a while figuring out how to disassemble it, but once I did, I realized there is the motor/mast assembly (A), and a 8'' metal tube (B) that connects to the outer metal piece & rubber grommet. Does anyone know if this is an OEM piece??

Anyway, My other questions:

There are two wires, one red, one blue that come from somewhere in the front of the car. I'm assuming they're for the power. Is this all I need to install any aftermarket antenna? On the antenna motor assembly, there was a separate wire that is a ground and was connected to the chassis.

Secondly, on part (B), there is a cable/antenna/aux type connector (similar to a cable jack) and it connected to a black wire with a needle terminal. Is this the actual wire that sends the radio signal to the head unit?

thanks for any help, I really want to clear up this info before I go any further in looking for another antenna.

----

[NISTECH]

the 2 wires you have are probably power and signal wires but they could also be reverse direction wires. in up position one wire is fed power and in the down position the other wire is fed power. best way to tell is to use a dvom,not a test light, put one end of the volt meter to ground and the red lead to one of the 2 wires. with the car off it should read zero volts. have someone turn the key to the on position and turn the radio on. if it is the up wire you should see voltage could be battery volts could be smaller you are just looking for a change. if nothing is seen have your buddy turn the radio off but leave the key on you are looking for the same results on the same wire. if nothing is seen this may be a signal wire. now start over again and do the same series of tests on the second wire. go with the same results. now if power is seen on both wires but one shows voltage when the radio is turned on and the other shows it when turned off this is your up and down supplies. after you get all that figured out you can use the instructions with your new antenna to wire it to the appropriate wires.

the "needle" one is your antenna wire for reception

[top-water_fisher]

TurDz,

I installed an OEM power antenna on my '98 240SX. Here's what I know. My antenna motor has a metal shaft angled up to the outside gromet. It also has a clear plastic drain tube that comes out at the bottom. The part number at the local Nissan dealer is 28200-65F06 (about $200).

There's a total of (4) lines: AM/FM antenna signal, Ground wire, 12 volt 7.5A battery wire, Power up/down signal from radio deck.

--AM/FM antenna signal (original body harness color is black): It is the thickest cable with the single pronged jack.

--Ground (original body harness color is black): It sounds like you know which wire is the ground. You said it was connected to the chasis. But, I ended up splicing the ground to the forward body harness ground line. (Shouldn't matter, though.)

--12 volt 7.5A battery line (original body harness color is orange with green strip): You can locate this wire by using a volt meter. With car turned off and key out of ignition, place the negative probe against the ground cable and the positive probe against the suspected wire (red or blue wire according to your info). If it reads 12 volts, you have located the battery line.

--Power up/down signal (original body harness color is green with white strip): Easy, it's the remaining wire.

Please note that the original harness wire colors are not found in the rear tail harness section. They are found in the forward body harnes section fo the car. Since your car didn't originally have power antenna, the wires won't be found at the back. I hope this helps.

top-water_fisher

[TurDz]

Thanks for all of your help everyone.

The black thick wire is indeed the AM/FM signal, I'm sure about that now.

Here is a diagram for more reference...



The mini relay box seems like it came with the aftermarket antenna.

As you can see, I had a power antenna that worked with three wires, and one ground wire which comes straight out of the antenna motor to the chassis.

Also, is the metal shaft that connects to the pieces which stick out of the car (rubber grommet, metal piece) an OEM piece?

[top-water_fisher]

TurDz,

I'm not familiar with aftermarket power antennas. However, it appears the metal shaft that you illustrated is not an OEM part. It looks niether like the OEM fixed mast antenna shaft or OEM power antenna shaft. I checked out my old fixed mast antenna shaft. The coaxial antenna signal terminal on the OEM shaft is not threaded at all-- it's a simple plug in terminal. After a closer look, the coaxial antenna terminal on the metal shaft is also a male adaptor (single prong in the middle). Your illustration shows the male adapter on the coaxial cable line. The OEM metal shaft also measures 12-3/8" long, which is different than the 8" you measured. Lastly, the upper lip of the metal shaft that fits below the outside rubber base(grommet) should be angled just like the way the outside rubber base is angled, thus creating a clean fitting seal.

--top-water_fisher

[TurDz]

Sorry, I was guesstimating the size of the metal shaft. It is actually more like 9''.

Also, the terminal on the metal shaft end IS a male adapter, the drawing is off on that part. Also, at the upper portion of the metal shaft, there is also an extra metal bracket to make a secure fit.

so the red and blue wires are not OEM, correct? I followed them through the rear sear and under the driver side plastic panel and it does indeed look aftermarket.

I'm pretty sure that I'll just go with a quality aftermarket antenna since the setup I have now is nearly plug and play for one.

thanks for your help top-water fisher.