92 chevy c3500, 350, L480E trans. Been thru it, can't get a signal to the dash from the DRAC module & don't know why. Have good AC volts, within spec., from the VSS, got the 12v & ground to fire it, got output from the DRAC so as to see it on a scanner. Checked the outputs to the ECM & RWAL module & have all them but the blue/black wire to the speedo is dead. Replaced the DRAC with another to no avail, put both modules in another truck & they work in that truck, checked all the connections at the module & they all ohmed out but replaced the pigtail too just because I was deadended. Still no signal. Snipped the wire to the speedo & checked it that way too in case it was shorted between the module & speedo, still nothing. Anybody with experience here that may have seen such a clusterfk, your input will be appreciated. Thanks, I need the good luck this time.
Electronic speedo, chevy truck
Sep 17, 2005
1 Replies
Ok, so I'll answer my own post. After a weekend of ball scratchin' & a case of beer & a little Wild Turkey, went back at it Mon. mornin' with a refreshed but somewhat hazy mind. Truck has no cruise so previously ignored that output wire. It was found to be dead (no voltage compared to the other trucks wire showing a signal) Disconnected it & the speedo worked. Moral of the story, expect the worst. The Mitchell on demand doesn't have a diagnostic flow chart that ends with, " some complete idiot, for some reason put a scotchlock & a wire that dangles to ground onto your cruise output wire, disconnect wire, have a nice day" This situation disabled ONLY the speedo output wire, all other outputs were normal compared to the other truck. Food for thought.
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