On the 2000 Chevy K1500, when there is “No Communication” between the DLC and the scan-tool, check fuse #47 labeled as “CIGAR” in the fuse box to see if it’s blown. This fuse also protects the Cigar lighter, and more times than not, this is the root of the problem. Remove the cigar lighter receptical and unplug it. Install a new fuse. If it blows again, there is a wiring problem in the Data Link Connector. If the fuse does not blow, inspect the wiring harness to the cigar lighter for any signs of damage. If the visual inspection checks ok, the problem is in the lighter receptical itself.
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