Numerous Electrical Issues
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Heel & Toe
Joined: Jul 2021
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Numerous Electrical Issues
Ok, my 2002 C5 is having several electrical issues. NO ITS NOT THE GROUNDS. I have removed, cleaned or replaced all 9 grounding locations on the vehicle. I have replaced all wiring near the starter. Installed a new battery and voltage is good. I have run computer diagnostics. The DIC is just dead, the door locks and window functions wont work. I have replaced all controls in the doors. I can unlock and operate windows from the computer just fine. The DIC says, no communication. Could this be the BCM? This all started in a rain storm last year. Does the BCM control the DIC? Everything else appears to function just fine, at least that I know of. Whatever it is the 3 issues are tied together. I do not beleive the DIC has to be rebuilt.
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Joined: Sep 2013
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Follow this procedure if you can’t communicate with any module !!…you may have a serial data problem…will the car start and run ??…I’ve never seen the DIC say “no communication”…a no communication with what module ??…your BCM may have gotten wet…clean the cowl drain “utters”…that is most likely why your BCM got wet.
1) Locate the 2 Star Connectors to the left of the BCM and remove the buss bar or “comb” from star connector #2…it has 4 wires on it…see if the car starts…if no start go to next step.
2) Now remove the comb off the other star connector leaving both combs removed…make a jumper wire and jumper the BCM to PCM…light green to dark green wire….if car starts you have a module other than the BCM and PCM on star connector #1 pulling the data bus down….if car still doesn’t start the module pulling the bus down is either the BCM or PCM…go to next step.
3) Take your jumper wire and connect from the purple wire (data bus wire) to the PCM (dark green wire)…now with your scan tool see if you can communicate with the PCM…if you can now communicate the PCM is good and issue may be the BCM…to see if the BCM is indeed bad take the jumper wire and connect the jumper now to the BCM (light green)…with a scan tool that can communicate with ALL modules (NOT a code reader) and if you can’t communicate we can “assume” BCM is bad…for single module “no comm” you want to check the powers and grounds to that module.
1) Locate the 2 Star Connectors to the left of the BCM and remove the buss bar or “comb” from star connector #2…it has 4 wires on it…see if the car starts…if no start go to next step.
2) Now remove the comb off the other star connector leaving both combs removed…make a jumper wire and jumper the BCM to PCM…light green to dark green wire….if car starts you have a module other than the BCM and PCM on star connector #1 pulling the data bus down….if car still doesn’t start the module pulling the bus down is either the BCM or PCM…go to next step.
3) Take your jumper wire and connect from the purple wire (data bus wire) to the PCM (dark green wire)…now with your scan tool see if you can communicate with the PCM…if you can now communicate the PCM is good and issue may be the BCM…to see if the BCM is indeed bad take the jumper wire and connect the jumper now to the BCM (light green)…with a scan tool that can communicate with ALL modules (NOT a code reader) and if you can’t communicate we can “assume” BCM is bad…for single module “no comm” you want to check the powers and grounds to that module.
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