Hi guys. There are a few radio models that have a circuit that senses when one of the speaker wires is grounded. When it detects that it will not turn on that output circuit to protect the I.C. Usually all the speakers on one side of the vehicle run on the same I.C, in this case, the left side. Sometimes you can determine which speaker has the problem because it will produce a little weak sound and the other one will be totally dead. In those cases the shorted wire bypasses part of the protection circuit so some sound gets through.
A grounded speaker wire can also damage an output I.C. And the same thing would happen to another radio. Since the early '80s all car radios from all manufacturers have 6 volts on all the speaker wires and none of them can be grounded. Before you go any further, take the radios to a larger salvage yard that has a test bench and ask them to test both for proper operation. If the left channel is dead on both of them don't stick in any more radios yet.
There can also be a remote amplifier in the van that has a dead channel. Unlike Ford and GM radios that have to be paired with an amp when they're designed that way, Chrysler amps do not change volume or power so an aftermarket radio will work normally with or without it. Those amps just modify the tone for the shape of the vehicle. Look at the seven terminals in the black plug for the radio. If it only has six wires, the van does not have an amp. The wire at the end away from the key way is the turn-on wire for an amp and / or a power antenna. If that wire is missing there can't be an amp. If that wire is there, there COULD be an amp but not necessarily.
There can also be two dead speakers on the left side. Before you get too involved, switch two of them side-to-side. If you get sound from the one on the left now, that proves the other speaker is defective, not the radio or wiring. A lot of the older Infinity systems had little amplifiers bolted right onto the speakers. Those were at least $130.00 speakers, and I fixed a few for some used car dealers. They will have four wires in their plug. I also recently fixed a pair for a fellow that had problems in the crossover networks. They also had little boxes with a plug attached but they just use two wires. You can make those work yourself by adding one jumper wire but it may sound different than the one on the other side.
Once this is solved if you want to upgrade to a really nice radio, look for a cd / cassette combo radio. Most of them are built by Mitsubishi for Chrysler and are real high quality. They will have "supplier # 28046" on the model number sticker on top. I'm surprised you still have the two plugs on yours. Those were around until 2003 in the full-size vans, but cars and minivans started switching over to the single 22-pin plug Jacobandnickolas referred to by 2000 or 2001. There are only a few round-face models like you have that use the two plugs. I sell a lot of them at the nation's second largest old car show swap meet, 50 miles from me, for upgrades when people buy used cars. They're my most popular models. They should be matched with an amp though if possible. The Infinity models put out much less bass and it is made up in the amp. Without the amp you'll have to turn the bass way up to sound right. A non-Infinity radio puts out normal bass and will sound terrible with an amp unless you turn the bass way down.
Friday, March 22nd, 2013 AT 3:20 AM