1999 GMC Yukon Start

I kind of had the same problem with my 99 suburban, the passlock bypass module died, car would not start with key or remote start.  I put the cut yellow wire from ign cylinder back together and car started. I took it apart a week later to measure resistance on the Ing cylinder (523 ohms on mine) put the yellow wire back together and would not start. I tried disconnecting the battery, nothing worked. I ended up putting a battery charger on it for about 15-20 min and then it started???? Might help

Jeff

Did you check the owners manual,security light should be in the upper right corner of the speedometer cluser if its a early 99 or left side if its later 99.

Most likely it was not the key that fixed it since the resistor is in the lock tumbler, it seems like it takes time for the passlock to settle down.

Jeff

No I would hook everyting up, before trying to start it.  It gets confused when it doesn't see the resistance(basically the proper voltage)  from the lock cylinder.

jeff

No, I would hook everything up before I tried to start it.  It gets confused if it does not see the proper resistance from the lock cylinder.  And then you KNOW  what happens.

Jeff

when you cut the yellow wire you basically have two wires, one that goes towards you key or lock cylinder, that half of the yellow wire connecst to the yellow wire on the 555L, the other half of the yellow wire you cut goes to the BLACK / YELLOW on the 555L, you also need to attache the Black wire on the 555L to the ORANGE / black wire coming from the lock cylinder DO NOT CUT this wire just attach to it. The other wire connections on the 555L are pretty easy. After you connect everthing follow the instructions on the 555L to auto learn.

Jeff