One more thing I thought of later was my entire reply does not apply to your car. That is because you have a separate Body Computer and radio. GM has pulled a number of tricks to stop me from repairing their radios for dealers around my state. One was to no longer allow me to buy their radio service manuals after the 1994 model year. Next, they had a one hundred percent failure rate on their laser assemblies on their CD players all through the 1990's, and with no service manuals, I could not get part numbers, so I could not order parts. To avoid the high cost of going through the dealer to one of their two remaining authorized repair centers, most people just went to Best Buy to get a decent aftermarket radio. This is where my story begins. To combat that, GM started building their Body Computers into their radios on some 2002 truck models so you could not remove their radio. If you did, you would lose the turn signal click, power locks, interior lights, and other systems. When you needed a new Body Computer, you were actually buying a new radio, and the dealer had to [program it to your vehicle. This did not extend to all the other truck and car models for possibly another eight to ten years.
The aftermarket industry fought back again by offering a "radio relocation kit". That was a long wiring harness that allowed you to mount the original radio under the passenger seat, and just cut off the speaker wires and run them to your new aftermarket radio in the dash. That way you still had the required Body Computer/radio connected and working.
Chrysler also had some similar issues with matched Body and Engine Computers, but the problem was a little different. It is worth mentioning in case someone researching this topic reads this. Some early 1990's models were available with or without the factory anti-theft system. That was built into both of those computers. When you installed a used computer into your car with the anti-theft system, if the used computer did not have that programming, it would learn it from the other computer the next time the ignition switch was turned on. Basically, you could use any computer if your car had the anti-theft system.
It is when your car does not have the anti-theft system that it gets messy. If you install a used computer that also does not have it, it will work just fine, but if you get your hands on a computer that was in a donor car that had anti-theft, that is burned in permanently and cannot be undone. When you turn on the ignition switch, the used computer will teach the other one that it should be upgraded to anti-theft status, so now both of those computers will only work in any similar model that has the anti-theft in it. Since your car does not have anti-theft, both computers are now self-taught to wait to see the disarm signal before they will let the engine start and run, but there is nothing on the car to generate that signal. You can pull your hair out swapping computers in and out until you finally hit on two at the same time that do not have the anti-theft programming. Since you typically do not know the history of the donor cars in the salvage yards, the safer way is to buy a rebuilt computer from the dealer. They all come with no anti-theft programming, then the new one will learn it from the other computer if that option is on that car.
Regardless, please pop back with an update when the radio is working. Thank you for adding to this post as it is likely to help others.
Monday, September 17th, 2018 AT 9:51 PM
