Strange Electrical Issue on 1991 300CE
04-09-2012, 06:23 PM
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1991 300CE
Strange Electrical Issue on 1991 300CE
My friend recently bought a 1991 300CE, and asked me to put a new stereo in it. The stock Becker head unit would not accept the code we were given from a MB dealership, so we were unaware of what components were still functional in the car. This car has the odd arrangement of the head unit in the dash, and the tuner, CD changer, and dual amps in the trunk.
I removed the stock Becker unit, the CD changer, and the amps in the trunk. He had purchased a Kenwood head unit to replace the stock one, and a powered subwoofer for the trunk. I hooked up the new head unit with no drama (I've installed many systems in the past, but never in a MB), then ran new cables to the rear for the rear speakers (since the speaker connections in the front are only for the front speakers), and a preamp cable and turn-on wire for the subwoofer in the trunk. I connected the rear speaker cables directly to the rear speakers. To power the subwoofer in the trunk, I used a power connection from the CD changer/tuner that I had earlier removed.
Everything worked great for a few days. Then a fuse blew in the panel under the hood, fuse #9. When I tried to replace the fuse, it immediately blew with a nice spark, as soon as it was installed. Subsequent attempts at replacing the fuse failed as well. I disconnected the stereo head unit and the subwoofer, tried the fuse again, and again it blew immediately. Also, I noticed that the fuse on the rear of the new stereo had NOT blown.
What's odd is that the offending #9 fuse does NOT control power to either the head unit in the dash, nor the subwoofer in the trunk. Fuse #1 is that circuit.
My question is, why does fuse #9 blow as soon as I attempt to replace it? Sounds like a short to me, but how to trace it out? It seems strangely coincidental that this issue started right after I installed the new sound system, but yet that circuit seems unrelated to the one that now presumably has a short. I'm stumped...anyone have any suggestions?
Thanks!
-Kevin
I removed the stock Becker unit, the CD changer, and the amps in the trunk. He had purchased a Kenwood head unit to replace the stock one, and a powered subwoofer for the trunk. I hooked up the new head unit with no drama (I've installed many systems in the past, but never in a MB), then ran new cables to the rear for the rear speakers (since the speaker connections in the front are only for the front speakers), and a preamp cable and turn-on wire for the subwoofer in the trunk. I connected the rear speaker cables directly to the rear speakers. To power the subwoofer in the trunk, I used a power connection from the CD changer/tuner that I had earlier removed.
Everything worked great for a few days. Then a fuse blew in the panel under the hood, fuse #9. When I tried to replace the fuse, it immediately blew with a nice spark, as soon as it was installed. Subsequent attempts at replacing the fuse failed as well. I disconnected the stereo head unit and the subwoofer, tried the fuse again, and again it blew immediately. Also, I noticed that the fuse on the rear of the new stereo had NOT blown.
What's odd is that the offending #9 fuse does NOT control power to either the head unit in the dash, nor the subwoofer in the trunk. Fuse #1 is that circuit.
My question is, why does fuse #9 blow as soon as I attempt to replace it? Sounds like a short to me, but how to trace it out? It seems strangely coincidental that this issue started right after I installed the new sound system, but yet that circuit seems unrelated to the one that now presumably has a short. I'm stumped...anyone have any suggestions?
Thanks!
-Kevin
04-16-2012, 01:10 AM
#2
nether the new owner or you have any history connected with the car so its likely not related. Sorry I don't know what #9 circuit consist of.
Maybe this
http://www.justanswer.com/mercedes/1...per-motor.html
Maybe this
http://www.justanswer.com/mercedes/1...per-motor.html
