The Impala, part #2

     The main question asked at this point is how to proceed. It quite often happens that the information that is passed onto the technician about the symptoms that a car is displaying turns out to not match what was initially described to him/her. The Airbag (SRS) and ABS lights flashing on, instead of the turn indicators suggests a completely different issue, and the scan tool is now the next thing to bring into play.


     So connecting the TechII scan tool, and going straight for the Airbag system there was no communication found with that module. Other systems were communicating on the data bus, and they of course had active codes for the airbag module communication failure and historical codes for multiple modules losing communication. When a module has fallen off of the data bus the thing to do is confirm power and grounds. In this case with the turn signals are also being affected, looking for something common to both systems makes for a logical plan and what they share is the same power connection from the ignition switch. The fuse for the turn signals is in the fuse block on the drivers end of the dash, and measuring power on that fuse showed 7v. Meanwhile any fuse that wasn't getting power from the pink wire pin "B" of connector #2  was a showing battery voltage of 12.2v. That's a big voltage drop to that circuit.


     The customer was then brought to the car and shown what we had found, she didn't have a turn signal issue, she had an ignition switch problem that was even shutting down her alternator at times and it was a good thing we squeezed this in. It was kind of fun to show her the turn signals not working, which is the symptom that she noted, then show her the airbag module not having communication with the scan tool, and then by jumping power to the turn fuse, all of the systems that were affected came back to life. When the jumper was removed, they all shut right back down, which by the way is exactly what the car was going to do to her real soon, stall out and leave her stranded somewhere. That pin of the ignition switch also powers up the fuel injection system, and all she had to do was drop just a little more power and that would have shut the engine down too. At this point it was time to get a charger on the battery, and get a new switch ordered and installed and we had her back on the road in a couple hours.


#Tech II , # Airbag, #ignition, #ignition switch, #SRS, #battery, #module, #fuse, #jumper wire, #data bus, #turn signal