Blue Angel

02Z, had pulled the wiper transmission to wash out the cowl after mice had made a nest.

I plugged the wiper transmission in and the alarm sounded. I opened the door and put the key in to silence the alarm. Now the car won’t start; no relays in footwell clicking when keyed to start position and clutch pedal to the floor.

The security light is never on (except for a couple seconds after switching key on, then it goes out with the rest of the dash lights), but the door chimes as if the key is in the ignition when the drivers door is open even without the key in the ignition.

I’ve tried leaving the ignition on for 10 minutes (even though the security light is off, no change. I’ve disconnected the battery and shorted the + and - terminals for 20 seconds, no change.

I’ve read a ton of forum posts and nothing seems to mention the door chime and no security light. The only codes I get are BCM B0432 Rear Defogger Circuit, SDM U1040H (?), IPC U1040H Loss of Communications With TCS.

The only clue I have is I used to have the Service Column Lock message and now I don’t. Not sure why that is.

Anyone run into this one before? Both relays in the pass footwell are fairly new and I’ve already rebuilt the ignition switch, and I’m very familiar with the intermittent nature of their related issues. Brand new battery and solid connections. There’s been noting intermittent here, just worked perfect one minute and not the next after triggering the alarm.

Ideas?

mmartinez

I would start by checking that your battery is fully charged. The security light comes on when you first turn the key to the on position, the gauges sweep, other indictors come on then they all go off, the security light going off is normal, if it stayed on that would mean that there's a problem with the VATS.

Blue Angel

Thanks for the quick reply!

Battery is fully charged (12.0V on DIC with key on, HVAC and radio off). It's also a brand new battery only two weeks old and has plenty of cranking power.

Yes, security light goes out after gauge sweep which is what's confusing me. I haven't come across someone else reporting this specific issue. I shot a quick video of the sequence including the chime with door open:


Everything was working great until I plugged the wiper motor in with the key off (and security ON maybe?) which set off the alarm.

Blue Angel

Another thought. To get the wiper transmission out I had to cycle the wipers and turn the key off with the wiper transmission fully to one side.

Later when I plugged in the transmission it immediately went back to its rest position, which would have drawn current. This is when the alarm triggered.

Blue Angel

An observation: the clock on the radio doesn’t shut off, even after sitting twenty minutes and locking the doors with the key fob.

Still stuck with this no start situation.

Blue Angel

Looks like my delayed accessory power is not shutting off for some reason. Even with the key out after opening the drivers door, all of my accessories are operational and I can still power the windows up and down.

The plot thickens...

Blue Angel

Now this is truly messed up. While I was taking the knee bolster panel off to get at the wiring below the steering column, I accidentally moved the wiper stalk all the way to the top and my accessory power shut off. I tried it a few times and it was repeatable, and with the stalk all the way up my security light started blinking as it should.

So I tried starting the car and it fires right up! The only thing is the wiper stalk needs to be in its upper position which means the wipers have to be going full blast to allow me to start the car. Wierd.

I’m guessing there’s a relay or something that’s stuck, or the BCM is completely toast and is sending out improper commands. Anybody have a thorough wiring diagram for the C-5 steering column and ignition controls?

mmartinez

Weirdness reigns supreme, wish I had more in depth knowledge about C5 wiring and controls, hopefully somebody has experienced this problem and will respond to this thread.

Blue Angel

So I'm not sure what was actually going on with my car, but this morning the issue "fixed" itself. I'm not sure how, but perhaps messing with the wiper controls last night allowed something to reset? No Idea.

All I know is, now the car seems to be fine. I drove it today and all seems well. It doesn't go into "security" mode when locking with the fob (I think it's supposed to whenever locking with the fob or with the power door lock button), but I don't remember if it did that before or not. I'm pretty sure it did, but whatever, I'm OK with it as it is now.

If anyone else stumbles upon this thread in the future and is going through something similar, I hope this helps them out.