smaginnis

Ok so I bought an 02 Tahoe and the dealer had an "on time" device pit on it at a local garage. Well when they put this device on, the next day I went out and started the truck. Went to leave and about 5 min after I statred driving all the dash guages went out , the sevice engine light came on and the trans quit shifting.... Dealer took the device out reset the codes worked for a day.... did the same thing again had another shop pull the codes... P0785 2-3 shift silinoid circuit... P1860 TCC shift silinoid... B1367 Device Ignition 0 circuit low. what could this all be because when the guages come back on if you shut the ignition off and start it back up the trans shifts fine until the guages go out again, then you only have 3rd gear and nothing else.

GMMerlin

I have no idea what an "on time" device is, but from what you describe, it looks like you have a bad ignition switch

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Jeremy-WI

Does this "on time" device start the vehicle? What does it do?

It could be that the installer tapped into the ignition 0 circuit and severed the wire enough to cause this problem, scotch-lok type taps are known to do this. If there is no damage to the wire then it is probably an ignition switch issue. The ignition 0 wire is most likely white and close to wires colored red, pink, and orange under the steering column