The FM Modulator

Installing the FM modulator is a pretty straight forward procedure.  The modulator itself is quite compact, measuring approximately 2 1/2” x 3” x 1/2”, with several wires protruding from both sides.  I needed to find a place behind the dash to mount the unit as well as several key wiring spots. For those of you who have never taken your Jeep’s dash apart, it turns out to be a very simple process... much easier than any other vehicle I’ve owned.  This turns out to be a good thing, since you will be dismantling most of your dash for this installation.  Start by pulling the cover from under your steering wheel.  Remove the two screws, and then just unsnap it. Next, pull the top vent cover (the piece that has the VIN number cutout).  This piece simply snaps out.  Once that is done, remove the two screws that holds the main dash piece that covers your radio, vent controls, etc. Once the two screws have been removed, simply unsnap the piece out. Note:  One of the keeper brackets on my dash also came out (it is a snap in). I simply snapped it back in before I reinstalled the dash cover... just be careful you don’t lose any of these “keepers” when you pull the cover off. Go ahead and remove the glove box also.

Since I already had the Roady installed (see page 1), I needed to remove the  power cord I modified when I installed it.  I had previously routed the Roady’s power cable up along the left corner post behind the plastic covers which completely hid it from view. I had to extend the included cigarette power cord that came with the Roady due to its length.  The cables that come with the modulator are plenty long enough so no extension will be needed this time.  I mounted the modulator on the left side of the steering column to a bundle of wires using zip ties. I then routed the power and audio cables up the same path that I had previously used for the original power cord, hiding them behind the plastic covers.  Next, I ran the two antenna cables behind the dash to the glovebox area.  The Wrangler engineers conveniently located the cables behind the glove box. Don’t hook them up yet.  Now it is time to hook up the ground cable. The lug or terminal that comes pre-attached to the modulator is very small.  So, you have two choices here.  You can find a place in the metal frame and drill a small hole, then attach it with one of your own screws that fit the lug. Or you can do as I did, and install a larger lug and use one of the many screws already present.  Just make sure that the ground lug touches the metal frame by putting it under the plastic if necessary.

Only one more wire to go before you can power it up and try it.  This was the hardest part of the installation, for a couple of reasons. My first choice for a power tap was one of the cigarette (or “accessory”) power outlets.  I had originally believed one of them to be switched with the key.  This is how I had originally hooked up the Roady, with an external power adaptor into one of the cigarette ports that I thought was switched. I connected the red positive lead to the back of one of the cigarette ports (I tested with a multi meter first - I swear it switched on and off!) using a vampire power tap, only to find that the Roady was always on irregardless of the key position.  This simply wasn’t going to work, and visions of a dead battery flashed before my eyes. I searched under the dash and under the hood for a switched power tap or terminal, but alas, I was unable to find one. So my next choice was the power connector on the back of the radio. Getting the radio out is a little tricky the first time, since you cannot see why it won’t come out.  Turns out there is a bracket in the back holding it in and stabilizing the back end.  To remove the bracket, there are two nuts that need to be removed up on the top back part of the dash (you removed the cover earlier). There is a thick wire looped around a stud with a nut holding the thick wire down.  Remove the nuts, and pick up the bracket. Jiggle it around a bit and it should come loose. Now carefully pull the radio out.  There is the main power/speaker connector on the rear-left, and the antenna connection on the rear-right.  Disconnect the antenna cable connectors that are behind the glove box (you cannot pull the antenna connector out of the back of the radio - it has a physical retainer to prevent it working its way out). Simply pull them apart.  Then as you pull the radio out, help feed the antenna cable through so there is enough slack.  Once the radio has cleared the dash, disconnect the power/speaker connector. As you look at the connector, you will notice two red wires on the far right. These are always-on 12v feeds.  We won’t be using those.  But next to one of them, the bottom one, is a pink wire.  Use a vampire tap and connect your red power lead from the modulator.  Plug the connector back into the radio. Route the antenna cable back to the glove box area, and connect it up using the modulator’s connectors. 

At this point, everything should be working. I recommend testing it at this point before reassembling your dash.  The modulator has three frequency settings, select one and tune your radio to match.  If you get sound, it’s time to put it all back together.  The only tricky part is getting that bracket for the back of the radio in. You will need to get your hand back behind the radio and align the bracket to get it to go in.  It went in on my second try, once I realized that the bracket swivels and got it align correctly.  Once the bracket is in, reinstall the radio’s screws and the nuts for the bracket. Now just reinstall all the covers in the opposite order you took them off, and walla you are finished!  By the way, I zip-tied all the wires to make it look neat as well as keep the wires from getting tangled or wrapped up on anything under the dash.

I have been an XM user for over a couple of years now, and have two different systems, as noted earlier in the article.  Using this FM modulator is by far the best sound I have gotten from the XM radio yet, and well worth the price and effort of installation.. None of my car radios has a direct input jack (some newer after-market radios do), which would of eliminated the need for the modulator. I would rate them sound quality-wise like this from best to worse:

• Direct input (use if you have - sound quality will be excellent - but the connector may be in front of radio so wires may show)
• FM modulator (direct connect, very clean install, very good quality sound)
• Cassette adaptor (works well, but ugly wires, and sometime the cassette adaptor itself is noisy)
• Built-in FM modulator (wireless type like the one built-in to the Roady. Works, but should be your last choice. Sound quality is like a good FM radio station. Strong radio stations can interfere and override at times.)

So there it is.  I am very pleased with the installation and the quality of the sound. My next and last “upgrade” will be some sort of mount for the antenna. Currently, I still have the antenna attached to the metal hold-down clamp which works pretty well. But since the clamp is vertical, I sometimes lose signal when I am heading certain directions (the XM satellites are in the southern hemisphere of the sky, so the “ground plane” of the antenna is actually blocking the signal when mounted this way and I am headed north. So stay tuned, I plan on fixing it this week! UPDATE:  I took the advise of a fellow Jeeper and XM fan and routed the antenna cable out to the center of the roll cage and mounted the antenna there.  This seems to work very well. Not sure why this hadn’t dawned on me... must be all that padding.  The fit is a little tight with the hard top on, but looks like it will really do the trick. So far, my reception has been excellent. You can find Whodini’s installation article HERE.  Thanks for the tip Whodini!

I will be adding a few more pictures as well.  It got dark before I finished this project, so I will take more pictures when it is daylight again.