Sounds like you have a speaker problem. Disconnect the wiring harness from the eclipse and check the speaker leads with an multi-meter. Each speaker should read something close to 4 Ohms resistance. If 1 or more of the speakers read 2 Ohms or less, the radio is going into protection when you turn it up. You would need to replace the speaker/s. The only other thing I can think of is the power connections. Double check that the yellow and red wires are a solid connection to 12 volt power (yellow=constant, red=switched). Also be sure that the radio's black wire is going to chassis ground, there may not be a ground in the harness or it may be only getting ground through the antenna connection. Good luck
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Sounds like you have a speaker problem. Disconnect the wiring harness from the eclipse and check the speaker leads with an multi-meter. Each speaker should read something close to 4 Ohms resistance. If 1 or more of the speakers read 2 Ohms or less, the radio is going into protection when you turn it up. You would need to replace the speaker/s. The only other thing I can think of is the power connections. Double check that the yellow and red wires are a solid connection to 12 volt power (yellow=constant, red=switched). Also be sure that the radio's black wire is going to chassis ground, there may not be a ground in the harness or it may be only getting ground through the antenna connection. Good luck