I tried what you said above. on my tahoe, there is a security word in the top right corner of the dash. this is constantly on. The truck does start and shuts down after 1-2 seconds. if the fuel pump wasnt working, which was replaced ~~ 4 months ago, the truck would start. several days ago, the horn came on for no reason. when I went to the vehicle, while the horn was blowing, I only opened the door and the horn went off. weird. so far the fix above did not fix the problem. any other ideas?
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