1. [The 12 Volt](https://12volt.com/car-audio-video/vehicle-specific-audio): The 12 Volt is a website dedicated to car audio and video systems. You can find a large collection of car stereo wiring diagrams, including one for the 1991 Mazda Astina.
2. [Crutchfield](https://www.crutchfield.com/car/car-stereos/mazda/astina-1991/): Crutchfield is a leading retailer of car audio and video equipment. They also provide a database of vehicle-specific installation guides, which may include a wiring diagram for the 1991 Mazda Astina.
3. [AutoZone](https://www.autozone.com/repairguides/Mazda/Astina/1991-Mazda-Astina/Audio-Systems/Radio-Replacement-(W-CD-Cassette/Repair-Guide-Audio-Systems-Radio-Replacement-W-CD-Cassette-/): AutoZone is an auto parts retailer that offers free repair guides and documentation for various vehicles. Their website may have a wiring diagram for the 1991 Mazda Astina's stereo system.
4. [Mazda Tech Info](https://www.mazda.co.jp/en/manuals/): Mazda's official website sometimes provides technical documentation, including electrical diagrams, for older vehicle models. Check if a wiring diagram for the 1991 Mazda Astina is available on Mazda's website.
If you cannot find a 1991 Mazda Astina stereo wiring diagram using these sources, you may need to purchase a workshop or repair manual specifically for that vehicle model. These manuals typically contain extensive technical information, including electrical diagrams. You can search for such manuals by visiting an automotive parts store or by looking for digital copies online.
