I purchased a used 2000 Sierra 1500 (4.8L) and found that occasionally the shifter indicator was off by a notch (e.g. when in D the indicator showed N). Also the backup lights, when in reverse, would not come on but I could see them flash occasionally when moving the shifter to P. I thought this might mean a problem with the reverse switch (if there is one) on the tranny. I ignored it for a while and mention it now because is might lead to a diagnosis of my sudden serious problem. Another seemingly unrelated repair was done. I turned the rotors and replaced the pads. After that things went crazy. The ABS light came on, the brake warning light frequently flashed but not when actually braking and it would not shift out of 2nd. It is my guess that the problem is a transmission switch or indicator or whatever electronic part tells the computer what is going on. Or it may be the computer itself. Given all this odd behavior, does someone have any idea what the problem might be? TIA.
One additional note that I forgot. On occasion, when riding a speed, the doors would unlock, which again seems to imply a transmission indicator issue.
One additional note that I forgot. On occasion, when riding a speed, the doors would unlock, which again seems to imply a transmission indicator issue.
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