Sound System Upgrade (part 1)

Replacing the head unit and speakers:

Upgrading the stock (~25 year old) sound system in the car is a must. While the components still work great, they leave much to be desired, especially the stock cassette head unit. Replacing both the head unit and the 4 speakers is relatively easy. The stock head unit is a double DIN, which means it takes up two slots in your front panel. Modern head units can be either 1 DIN or double DIN. I chose a single DIN unit to free up some space for a switch panel. There are four speakers in total, two on the front dash (4″ diameter) and two behind the driver in the upper corners at the back of the cabin (3.5″ diameter).

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To remove the old head unit you need to take a few small screws out of the front panel. The following schematic image from the factory service manual makes this clearer. Wiring in the new head unit is fairly straightforward, there should be instructions in the box. You can get an adapter harness (Toyota) to make this job easier. To make sure you are connecting the correct wires, you can use the radio wiring schematic.

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I kept the stock amplifier (located below the drivers seat) as I was not upgrading this at the time. Once the wiring was complete, the new system was definitely better than the old. By far the best improvement was the head unit, it freed up the space below for a switch panel as well as allowing me to play songs directly from a USB stick. The speaker upgrades were not noticeably much better than the stock units. For the future, if replacing working speakers, I would recommend going with something bigger (6″) and installing them in the doors, the small 4″ and 3.5″ speakers are not worth upgrading in hindsight.