Traiblazer intermittant no start
- Thread starter Robertjohn47
- Start date
Welcome to GMT Nation...
Check Fuse #28 for being Blown...Be careful NOT to spread open the Electrical Contacts inside of the Power Distribution Center...and courtesy the work of @Realism ... Read THIS Thread in order to Isolate, Remove, Clean and Re-Attach the Grounds-Bonding Straps Locations for the PCM and Ignition Switch:
gmtnation.com
Check Fuse #28 for being Blown...Be careful NOT to spread open the Electrical Contacts inside of the Power Distribution Center...and courtesy the work of @Realism ... Read THIS Thread in order to Isolate, Remove, Clean and Re-Attach the Grounds-Bonding Straps Locations for the PCM and Ignition Switch:
Electrical Ground locations
While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...
gmtnation.com
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Any activity from the instrument panel security indicator during these no starts? The PCM will not ground the start relay without the right security checks, even if everything else, like fuses, ignition switch, etc. are good.
I suspect passcode sensor (Hall effect) but I don't know how to check that signal via BCM via main computer
If you are referring to the chip in the key? The GMT360 did not get the PK system (except for the Saab). So I doubt thats it?
Suspicion without diagnostics can become quite expensive and produce no useful results.
Does the security light turn on when the key is turned to crank?
This doesn't have chip key only passcode sensor (hall effect) so I dont know how to check for this signal (microvolt)
Under normal operation, when the key is turned to the RUN position (not start/crank) and wait a few seconds the security light (or icon with padlock) should turn on for a brief time then turn off. We sometimes call this a bulb check that is done to demonstrate that the various lights actually do work and are not blown out. When the key is then turned to the start/crank position, if the security light turns on then that is likely an issue with the passlock system. The passlock sensor sends a signal back to the BCM once the key is turned to crank/start. I have seen both a solid security light at this point and I have also seen a flashing security light. They mean different things but both involve the security system.
If the security lught does NOT turn on when trying to crank then I would not suspect the Passlock system.
If the security lught does NOT turn on when trying to crank then I would not suspect the Passlock system.
If you DO see a security light that turns on AFTER the key is turned to crank then we can move on to how to test that system.
I currently have 3 of the Passlock sensors on my workbench and have them pretty much figured out. But lets see what you find out about that light first before diving into that.