Jensen MP3310 AM/FM/CD/MP3

I drive a 1989 Chevrolet Cheyenne 1500 (called C1500 by some) pickup truck in which recently I installed a Jensen MP3310 AM/FM/CD/MP3 receiver. I start the article with that sentence in the hope that it will be indexed by the search engines and maybe bring in other people who need advice on how to install an after market radio into these vehicles. I'm sure such advice exists somewhere out there on the world wide web, but I couldn't find it, and so made any number of mistakes that the rest of you could no doubt learn from.

My C1500 is a nice truck, especially considering what I've put it through over the years. However, recently the radio started giving me problems. Scratch that. The radio has always given me problems. To start with, when I first got the truck, the cassette player didn't work. Luckily, the cassette player was separate from the rest of the radio, connected with lots of wires and a big plug-in connector. Just by unplugging that connector, I was able to get the radio to forget that it had a busted cassette player and at least act like a radio again.

I was able to trade an old computer sound card for another cassette player designed for that model truck. Seemed that a guy at work had recently upgraded to a CD player and didn't need his cassette player anymore. He'd mounted it where the cassette player had been mounted, using a special adapter plate and a new wiring harness and blah blah blah. It all kind of ran together there at the end. I just knew that all I wanted was a working cassette player, and said that I'd never want a CD player in my truck badly enough to go to all that trouble.

I couple of years, I was eating my words.

The new/different cassette player worked for a time and I even got one of those cassette adapters that let you play pretty much any electronic device with an earphone jack through the cassette player, which in turn played through the radio, which in turn played through the speakers. The first device I used was a portable Walk-Person-style CD player. The second was a police scanner. A police scanner going through your zillion-watt radio and speakers is a bad idea. A little burst of static can deafen you and people in cars two lanes over.

The portable CD player would eat batteries pretty quickly, but it came with an AC adapter. Being a redneck turned geek, I of course had an inverter in my truck which could give me 120VAC on demand. This worked, but sitting the portable CD player on the seat next to me so I could reach the controls meant that every time I had to hit the brakes or make a quick turn, it ended up on the floorboard.

Eventually, the new/different cassette player stopped working. I pushed in a cassette tape one day and it just kept going, disappearing into the depths of the machine. I once again had to unplug the cassette player. No problem, I thought. I'll just make do with the radio.

Not too awful long after that, my starboard speakers went out. My truck has two speakers up in the dash, and two more about shoulder level behind the seat. Both the ones on the passenger side, front and rear, quit working one day. That both went out at the same time suggested to me a problem with the radio itself or perhaps the wiring very close to the radio. I thought of replacing the radio. Then I thought about how lazy I was and decided to make do with the other speakers.

I had previously kept the BAL turned mostly to the starboard speakers so that I could keep them loud enough to drown out the wind noise (I tend to drive with all windows open during the summer) without deafening myself. Turning the radio up loudly enough to make up for the missing speakers meant that the speaker that was shoulder level on the driver side was loud enough to make me physically ill. I got earaches and dizziness from the loudness right there next to my head. I had to FADE mostly to the front to make it bearable, but that meant it lost the contest with the wind noise.

So, while deciding on whether I was going to just re-wire or if I was going to have to replace all the speakers, I happened to also price a few CD players. The Jensen MP3310 AM/FM/CD/MP3 receiver was discontinued, on sale, and the salesperson didn't know how to run a cash register, so I got a pretty good deal. Now, to hook it up.

This is when I discovered that not only is the 1989 Chevy truck cassette player completely seperate from the radio, but the radio is completely seperate from the radio. That is, what I thought was the radio was actually a control panel, with the real radio being mounted back deep behind the dashboard somewhere. In fact, I could unplug what I thought was the radio and the speakers (the ones that still worked, anyway) could keep spitting out music, though the controls would go dead. This meant that the mess of wires that I thought were speaker wires turned out to be control wires. Which was bad because no matter how hard I looked, I couldn't find the power and speaker wires to/from the main radio.

I cheated. I mounted the Jensen MP3310 under the dash just like we used to mount old CB Radios. In fact, I used a bracket I borrowed from one of my old CB Radios. And since I couldn't find any speaker wires, I bought a $20 woofer box from the local auto parts store and tossed it behind the seat. I had tunes!

Unfortunately, since the speakers were basically speaking into my butt, I again had trouble with the music not being able to drown out the wind noise. Unless, of course, I turned up the volume so far that my entire lower body was vibrating, which is not nearly as exciting as it sounds. In fact, I was back to being physically ill.

Another trip to the local auto parts store and I had a pair of $30 midrange auto speakers. At first, I couldn't figure out how to get at the speakers in the dash, but eventually figured out that each of the two speaker grills were held in place with two tabs (into two slots, natch) and two metal clips. The metal clips were remarkably strong considering that they were 15 years old. The plastic they were glued to, not so much. But I managed to get keep one clip connected to each grill and didn't break any of the tabs, so I'm reasonably certain that they'll stay in place.

Getting the old speakers out was another story. They were each held in place with four bolts, and I didn't have a wrench that would fit them. I did have some sockets, but it took a while to find a socket wrench small enough to fit in there without busting out the windshield. Once I had the old speakers removed, I discovered part of the problem with finding the speaker wires. They went from the speakers into a metal track on the firewall and disappeared. I cut them off and stuffed them out of sight.

The new speakers, though cheap and ugly, had bigger magnets and deeper cones than the stock ones. I'm told this means that they are better designed and will sound better. I couldn't tell you. As far as the fine subtleties of acoustics go, I might as well be deaf. I do know that they can get much louder before the sound starts breaking up. Much louder than the stock speakers, and much louder than the woofer box behind the seat.

But because the new speakers are bigger and deeper, it was a royal pain trying to get them in the old holes. I had to compress the firewall sound insulation on one side and put all my weight pulling the dashboard away from the other side. Then I had to reverse the procedure to get the speakers back out because I realized that I hadn't hooked up the wires yet. Running the wires was fun. I couldn't use that metal track, so I just ran them as best I could along the path of some other wires. I had to remove the glove box and the stock cassette player (again) to see to run the wires from the passenger side, but the driver side was a straight drop from speaker to floorboard. It was a simple matter of standing on my head and dislocating my shoulder to route the wire around the steering column and down to the radio.

I'm kidding about dislocating my shoulder. I only pinched a nerve.

Now that I had tunes from good speakers, I was suddenly struck with a desire to make it look nicer. Perhaps it was the ribbing at work about getting a new CB Radio. Perhaps it was my crazy brother Tony telling me over and over that a crook could steal a radio mounted under the dash in less than a minute and he would know but couldn't tell me how. Perhaps it was that the new radio was mounted so low and so far away that every time I reached to adjust the volume, I spilled my coffee and drove my truck off the shoulder of the road.

I called the local Chevrolet dealer to inquire about the special adapter plate which could be used to mount an after market radio where the stock cassette player is mounted. I have been told by several people that such a critter is only available from your local Chevrolet dealer. The local Chevrolet dealer didn't have anything like that. They sent me to a local home/auto electronics store. The adapter plate they had didn't look like it would fit.

The stock cassette player is wider than any radio I've ever seen, but it's not very deep. The adapter plate added some extra depth, but it still looked an inch or so short. But the store guys assured me that they had installed any number of radios in Chevy trucks of this vintage and this mounting adapter always worked.

They then proceeded to attempt to sell me a new AM/FM/CD/MP3 receiver which was guaranteed to work with the adapter because, after all, why take chances? I told them I already had a new receiver. They also wanted to sell me a wiring harness that would let me plug selected receivers (on sale now!) directly into my existing radio using the same style plug-in connector as was on the stock cassette player. I told them that was nice, but my stock speakers weren't working with the radio, and I'd already wired new ones to the new receiver. The then tried to sell me an antenna adapter which would allow me to plug the extra-tiny Chevy antenna wire into the regular-tiny receiver. I'd already made it fit by bending the little ears on the plug out as far they would go, but let them talk me into the adapter, anyway.

I took the new adapter plate home, dug the receiver mounting cage out of the box, and spent the next hour cutting my fingertips to shreds as I tried to mount the latter into the former. The instructions clearly showed mounting the radio into the cage into the plate, then putting the plate into the dash, but that just wasn't happening. There just wasn't enough wiggle room for the angle the radio would have to hit in order for the dash plate to line up with the slots and tabs necessary to hold it in place. I was eventually able to worry the plate and cage into place, then slide the radio in, pretty much like the cage was eventually designed to do.

Then I had to pull the radio back out to hook up the wires. Naturally, even though I'd left a couple feet of slack in the speaker wires running to the rear boom box, the wires were too short to reach the radio's new position. I had to re-route the entire wiring bundle, which unfortunately meant that now the power wires were too short.

Never having found the power wires running to the radio and never being one to run a new wire from the fuse panel if I can avoid it, I had powered the radio from the glove box courtesy light, which I couldn't remember ever having used. I plan to eventually jumper back to said light so that it will work as well. This gave me 12V all the time, which I needed for one wire, but failed to give me 12V controlled by the ignition switch, which was needed for another wire. I gave the second wire permanent 12V as well, sure that as long as I remembered to turn off the radio when I parked it for the day, the clock showing all the time surely wouldn't drain my battery.

I unhooked the power wires and re-routed them, and suddenly I had enough slack to hook up the radio to its single huge connector. I carefully sorted the wires and folded them in behind the radio, then very carefully pushed the radio into place. I made several false starts, making sure I was not wadding up the wires behind the radio because I knew there was not a lot of space back there. The heatsinks on the back of the radio had some sharp edges. I could just imagine the wiggles and jiggles of driving eventually cutting through a wire, grounding something out, blowing half a dozen fuses, and losing headlights in the middle of the night somewhere.

Just as I was about to give up pushing and go tell the guy at the electronics store what I thought of his adapter plate, I heard a couple of small clicks and and the radio was seated. It's still a millimeter or so out from where I would like it to be, but the face plate mostly conceals that. I had tunes that looked good!

A few mornings later, I discovered that I'd either left the radio on or that clock and cute animated display were drawing more current that I thought, because the truck battery was mighty low. I was just barely able to get it started. That evening, I searched under the dash for a source of 12V that was controlled by the ignition switch. I finally found one. It was one of the half dozen wires running to the radio control panel. I wired it in and now I'm officially finished working on the darned thing.

If I ever get the urge to work on it again, I've got a couple projects lined up. First of all, I'm thinking of getting a new antenna. I've learned that the poor reception in my area was not due to the old radio or the lack of proper antenna connection to the new radio, as I'm not using the old radio and bought that antenna adapter. It might be the antenna. Or I might just live in a bad area.

The Jensen MP3310 AM/FM/CD/MP3 receiver has line level outputs for an amplifier. The receiver is rated at 180W (4x45W) and I don't think my cheap speakers are rated for much more, so I don't really think an amplifier is necessary or prudent. On the other hand, it's a set of wires that aren't hooked up to anything.

The Jensen MP3310 AM/FM/CD/MP3 receiver also has line level AUX inputs which I think will match the outputs of my fancy police scanner. I keep telling myself this is a bad idea because of that "burst of static at the end of every transmission making me deaf" thing.

Next time I go by the body shop, I'm going to ask how to get at the rear stock speakers. I may replace and/or re-wire them.

Finally, I've got a wire marked "power antenna" which I think feeds out 12V only when the radio is on. I'm certain that I can come up with something to use that. I could have it automatically power up the amplifier when I turn the radio on, but I'm not sure how much amperage that wire is supposed to provide. It might be safer to use that 12V to turn on a relay which will provide power straight from the battery. I think that's how my stupid brother Tracy had his last amplifier wired in. It was cool the way his headlights dimmed like that in time with the music.

What did I learn?

I learned that although there is a certain satisfaction in doing it all yourself, going to an auto electronics shop that specializes in radio installation isn't such a bad idea. Factor in time spent, frustration dealt with, and medical bills for cut fingers, and you'll probably come out cheaper.

Months later:

It's now months later than when I wrote that article, which I put off publishing until I could remove the radio and take some some pictures of it and the wiring. I still haven't taken any pictures, so I figured I might ought to go ahead and put up this article anyway before CD's go out of style.

The Jensen MP3310 AM/FM/CD/MP3 continues to work, but has its faults. I mostly use it to play MP3 files. A smattering of MP3 files will not work with it. They either won't play at all or play with very distorted sound. Some will play, but the MP3310 plays ten seconds of silence past the normal end of the song, sits there for a minute or two, gives some error message, then switches over to AUX input. Switch back to CD mode and it plays that same song again from the beginning. Once or twice, the MP3310 just stopped recognizing MP3 CD's altogether. I had to hit the little reset button with a pen to get it to work again.

If I had it to do all over again with a little more money, I probably would have went with a different brand or at least a newer model. Given the price, though, I'm happy with what I got.