I forget to say that removing the antenna does not affect the reception at all. So my guess the problem is somewhere there.
February, 19, 2012 AT 9:56 PM
There were no Daihatsu vehicles available in the US in 2007, so we have no information on it. The center conductor on the antenna cable goes to the mast, while the outer shield goes to body ground. No continuity. You can measure resistance from the body of the stereo to the body of the car and/or the base of the antenna. You can also measure resistance of the center conductor to the tip of the antenna. Both should be between 25 and 75 ohms, in theory.
Was your vehicle equipped with an amplifier? Not all are. In the US, the wire that switches a relay supplying power in the amplifier is usually blue with a white stripe. Do all other functions work? If so, it isn't an issue with an amplifier. It's in the tuner.