For the past 5+ years, when I disconnected my battery for an extended period, my car went into a coma for about 3 days. After reconnecting the battery, the instrument panel lights up, the fuel pump primes, but no starter engage, no radio power, no interior lights, no power locks, no trunk release. The windows work, the blower motor works, power seats, overhead display, headlights. The security relearn procedure never works. No flashing Security on the IP, only the red light flashing on the radio. And the the Recycled Air and Outside Air buttons on the AC panel both continuously light dimly and pulse like a computer hard drive light. I have never seen anyone report that symptom. I replaced the ignition switch the first time but it still did this. Three times, after about 3 days of sitting, I pressed the key fob and the lights came on and it started and had no issues until the next battery disconnect. A quick battery swap 2 years ago was successful. So it sounds like some sort of memory capacitor is discharging. In each instance though, the radio settings were saved.

This time is different. Its been sitting with a charged battery since Monday with no change. This time, it happened after I turned the car off at the 2nd store I was going to, no issues with the first (home) or second (store) start or the drive to the 2nd. While waiting for the tow truck, I visually inspected all of the fuses and reseated/jiggled the relays. A jump start attempt didn't change it.

This is the weird symptom that maybe someone will go Aha! While waiting for the tow truck I tried the relearn procedure with no success but during one of the On cycles, I opened the glovebox door and it continuously actuated the passenger door lock to lock while open, it repeated with several open/closes. But not the drivers side. It doesn't do it now.

My thought is that the Passlock sensor has failed because I've had no other issues that would seem to lead to bcm/pcm or starter motor or ignition switch and it always started and ran until I turned it off. There is no change with any of my 3 keys. The battery voltage is 12.7, 12.35 with the key on. Another thought is the driver side lock actuator failed/ is shorted.

I need to swap out my IP to get the fuel gauge repaired and I have another AC panel with all lights working to swap, so now is the time to replace the ignition switch, Passlock sensor, and/or lock cylinder. Any testing suggestions are welcome. Thanks.

Glen

 

Do you get 12v to the starter? Do you see numbers/values on the odometer? If yes to either likely its the ignition switch, I wouldn't recommend dorman, i used those before and had issues after a few months or immediately. Use OEM only for the ignition switch. As for ignition cylinder i have had fine luck with aftermarket.

 

Thanks, I have not checked voltage to the starter yet. Yes, the odometer displays the mileage. And the security icon does not flash.

Still no radio or crank attempt. Still dim flickering lights on both Outside Air/Recirculated Air buttons with the key off/out (see photo). Fully charged battery. Attempted the security relearn procedure again. From everything I've read, if the radio doesn't come on, it will not attempt to engage the starter.

I acknowledge but resist the likelihood of the switch because I replaced the switch 5 years ago after I first experienced these symptoms with the old switch after disconnecting the battery for an extended period and they continued with the new (current) switch after disconnection again.

When I get a chance, I'm going to check the output from the Passlock sensor but nobody can explain the flickering lights (the left side is always brighter) when the ignition is off and the (previously) 3 day waiting period.

 

The old mechanic in me says it's a ground issue. I've cured a lot by cleaning both ends of the battery ground cable and the ground strap from the motor to the frame. Also clean the ends to the starter.

 

Yep! what he said!!

 

Thanks, been there, done that. That was my 3rd failed effort on Event 1a after battery charge and security relearn failed. After event 1b, replace the ignition switch, same result. While researching the possible causes, 3 days passed and it had a restoration after no additional effort. Ditto for Event 2 and 3. For event 3, I didn't do anything but observe the 3 day waiting period after installing the replacement battery.

After doing some more research, I'm pretty positive the Passlock system is the issue. Which is the BCM, Passlock sensor and key cylinder. I suspect the BCM because it makes sense that previously it lost it's stored memory when the battery was disconnected and took 3 days to run diagnostics and recharge and decide it wasn't being stolen. I was hoping we had someone who replaced a BCM still hanging around here. I'm going to pull the BCM this weekend (if it doesn't wake up) and clean the contacts and record the part number. But it could be the key cylinder or sensor because this time it happened when I turned it off and removed the key and the door lock switch didn't work. Wish I knew someone with a Tech 2.

 

Have you tried a 'security bypass'? I had an issue a few times where mine just wouldn't start, and thought it was the neutral safety switch - much to my dismay is inside the bell housing. I talked to the guy at the Chevy garage, and he said he only ever changed about 2 of them, it was probably a security issue. Thinking back, every time it did it, it was unlocked, twice in my garage, and once in my Father-in-law's driveway. They took some kind of resistance reading from the key, and put a diode of the same resistance in the wiring. It's been a few years now without a recurrence.

 

Thanks. Yes, I'm aware of the bypass. Did you experience the same symptoms as me: no radio or time display, no interior lights, no power locks, no trunk release, flickering lights on the two buttons in my photo, restart after ~3 days? What did you do on those no-starts?

 

I had some weird stuff happening before, and had the BCM replaced, but as for the security bypass, it did everything but start - like it was in gear - which is why I thought it was the neutral safety switch. I still have an issue with a bad sensor/harness which makes the ABS light and traction control light come on. I guess electronics weren't meant to last 20 years!

 

You used to be able to buy a replacement harness from the engine harness to the plug for the speed sensor at the wheel. You had to splice it in so I just replaced the wires from the cradle to about 3 inches from the plug and haven't had the ABS/Service Traction issue since.