[MoPar~Man]

On my new '04 300m (which smells really nice now that I stuck an ozone generator in it for 45 minutes) there's a small black rectangular plastic box, about the size of the key fob, mounted or positioned right up close to the front of where the dash meets the windshield, in front of the red alarm LED stub. There are 2 plastic rods (about 6 inches long) that come out of the left and right sides of this box and lay flat against the dash. One of them has a plastic or rubber nib on the end, the other one the nib is missing and it looks like a copper wire (like #12 house wire) under it (so I guess these plastic rods are copper wire). There's a flat wire/cable (sort of looks like a RJ11 phone-cable) that runs from this box, goes under it and from there who knows where it goes.

What the heck is this thing? My '00 300m doesn't have it. Is it the radio antenna?

 

[EASY]

It could be a remote start system maybe, part of the alarm system, potentially the radio antenna if they moved it from under the back windshield

 

[sickboy]

Picture is worth 1000 words, but I’m guessing a receiver for satellite radio.

this is a more contemporary design

 

[MoPar~Man]

I just did a search for car antenna satellite radio and the first few hits with pictures showed almost exactly what I have being sold on amazon for $10 (model GP-AN-FM-03). I brought the item up and it does not mention satellite at all in the specs - just the FM band. Best Buy sells the same item and describes it as "wlaniot Universal Car Stereo AM FM Dipole Antenna,Hidden Adhesive Mount Radio Aerial for Vehicle Truck SUV Radio Stereo". Unless the stock '04 300m radio has satellite radio reception capability, I see no evidence that this car has ever had a satellite (Sirius/XM) radio installed.

So I have to conclude this is the factory am/fm radio that came with this car. Unless - unless the radio antenna would normally be built into the windshield (and connected at the rear-view mirror) and then possibly my car has a new windshield that either does not have antenna or they weren't able to connect the antenna and installed this antenna instead.

 

[valiant67]

It's not factory whatever it is. Either someone replaced the factory AM/FM antenna or the car had an auxiliary satellite radio tuner at one time (which may be entirely hidden).

 

[MoPar~Man]

. Either someone replaced the factory AM/FM antenna

Highly unlikely. Unless as I say factory antenna which I believe is normally in the front windshield became unusable because of windshield replacement.

or the car had an auxiliary satellite radio tuner at one time (which may be entirely hidden).

How do you operate a hidden satellite radio tuner?

And again, the style of this antenna comes up as being an ordinary FM antenna, not even good for AM. Antennas for satellite radio seem to look like a computer mouse (a box or disk at the end of a cord).

Do car radios with FM/AM/Satellte reception have separate antenna inputs for the satellite receiver?

 

[valiant67]

Highly unlikely. Unless as I say factory antenna which I believe is normally in the front windshield became unusable because of windshield replacement.


How do you operate a hidden satellite radio tuner?

And again, the style of this antenna comes up as being an ordinary FM antenna, not even good for AM. Antennas for satellite radio seem to look like a computer mouse (a box or disk at the end of a cord).

Do car radios with FM/AM/Satellte reception have separate antenna inputs for the satellite receiver?

As far as I know no factory 2004 Chrysler radio had an integrated satellite tuner. They relied on an external module. I don't know if the Mopar one then was controlled through the factory radio or if they used a remote and it played through an FM station.

I think the only way you'll solve the mystery is to pull the radio out of the dash and see what is connected to it while tracing the cable form the antenna on the dash.

 

[MoPar~Man]

I went out and looked at it though the windshield - it has a small red LED in the front, so right away this is likely not just a radio antenna. I took a flat head screw driver and pried it free of the dashboard (it was held there by a piece of thick doublesided tape. It has "R - 1" on the top and on the bottom it has "FCC ID: NAH8R304". FCC database search comes back with Compustar remote starter. (edit: It was NOT in the FCC database, but it did come up sort-of during google searches).

Now what do I do with this thing? I wonder if there's a way to obtain a matching remote fob for it..

Hey - wait a minute. I thought you couldn't start these LH cars unless the key is very very close to the ignition switch because of the RF code sent by the key to the car computer. Anyone want to explain how aftermarket remote car starters work with these Sentry Key vehicles?

Maybe they installed it, found that it didn't work, then just left the receiver there?

Where in the car's wiring would you hook this up? There must be something else somewhere (a decent if small relay I would think) to engage the start circuit.

 

[Dave Z]

The only other possibility I can think of is the auto headlight sensor. (I don't recall them having auto wipers, but I don't recall them not having auto wipers, either.)

Good question re the SentryKey system. I'd never thought of that, but since Mopar had auto starters, if I recall correctly, there must have been a way to wire starters in so they would work without unlocking the gear shift. (That's how our 2013 300C works, at least the factory remote start - the engine can be running without the car actually being on - you can't move into gear until you officially start the car.)

 

[Tomguy]

I was going to say it sounds like an aftermarket remote start. As for SKIM, did you get just one key? Chances are there's a box somewhere under your dash with another key in it for the SKIM system. That was the case when I bought my Charger R/T. Came with one key, but when removing the remote start system since I didn't have its fob, I found the second.

 

[MoPar~Man]

This is some sort of remote-start hardware. The FCC ID number embossed or molded into the bottom of the plastic box housing the receiver electronics matches a company called "Autostart" out of Montreal. The FCC assigns the first 3 characters of the FCC ID and that's what "NAH" comes back as. The FCC records (23 of them) for NAH run from 1997 to 2007 and pertain to frequencies of 304 and 434 mhz. More searching on this topic turns up some talk that yes, there might be a box somewhere containing a key (some versions) and in other versions there's a box that is wired to look like a key. What I find odd is that the LED on this windshield receiver box was not lit, so it was probably not being powered. I'll have to trace the wires to see what else (hardware wise) might be involved or still there.

 

[MoPar~Man]

Since I'm looking into why my headlight switch has no night-illumination back lighting, I pulled the lower trim panel off and found a small box, the size of a deck of cards, with 2 two-pin connectors that I pulled out. So I'll have to trace where those go. The box has this sticker: Transponder bypass unit, serial number, Date 2005-12-22, FCC ID, etc. I pop open the box and find a small PCB with a wide ribbon-cable arrangement making a loop from and back to the board, the loop big enough for the head of an ignition key to be inserted. The key is there. I take the key out, it can be inserted into the ignition switch, but it has no teeth (its an un-cut key) so it can't engage the switch. The only parts on the PCB besides the connectors are a couple of diodes and a relay. The investigation continues...

 

[06PTElectricBlue]

Since I'm looking into why my headlight switch has no night-illumination back lighting, I pulled the lower trim panel off and found a small box, the size of a deck of cards, with 2 two-pin connectors that I pulled out. So I'll have to trace where those go. The box has this sticker: Transponder bypass unit, serial number, Date 2005-12-22, FCC ID, etc. I pop open the box and find a small PCB with a wide ribbon-cable arrangement making a loop from and back to the board, the loop big enough for the head of an ignition key to be inserted. The key is there. I take the key out, it can be inserted into the ignition switch, but it has no teeth (its an un-cut key) so it can't engage the switch. The only parts on the PCB besides the connectors are a couple of diodes and a relay. The investigation continues...

My guess would be that the chip in the head of the uncut key it what is allowing the remote start to work.

 

[valiant67]

If it's a transponder bypass it probably goes to the WIN module (or whatever they called it that year) that read the key's chip and disarmed the security interrupt.

 

[Tomguy]

Cut the key, it'll be a good spare you don't need to pay for programming, since it is already programmed (assuming that this system worked at one point in the past). What you described is identical to the box my key came in.