Hey everyone, I’ve got a 2007 truck with 144,xxx miles, and it’s been acting really weird. A few months ago, I took a nap in the truck (keys out of the ignition), and about an hour in, the truck turned itself on! Accessory power, fans, radio—everything came on, but the engine didn’t crank.
When I tried to start it, it wouldn’t crank, and a red lock symbol flashed on the dash. I disconnected the positive terminal of the battery to stop draining it. After reconnecting it, everything worked normally again.
Fast forward to last night—my battery died (read 5 VDC), so I replaced it. Now the truck won’t crank again, and the same red lock light is flashing. Accessory power stays on even without the keys in the ignition. I’ve disconnected the negative terminal to prevent draining the new battery until I figure this out. Any ideas?
Finally, someone else! I’ve got the same year and mileage, and I’ve had similar issues. Shops replaced my alternator, checked wiring, and ran diagnostics but found nothing. I ended up having a kill switch wired to the terminal for $50. That fixed it.
Before the kill switch, a new battery lasted two days. I recommend turning the key to ACC for a few seconds before trying to start it after reconnecting the battery. Do you have aftermarket headlights? If you find a fix, let me know!
@Jessie
I did some digging online, and it seems like it’s going into ‘theft protection mode.’ That red lock symbol is for the immobilizer. I disconnected the positive terminal, left it for 30 minutes, and reconnected it. That fixed it for now.
I’m still not sure why it’s going into this mode, though. My theory is that it detected I was in the car (maybe because of seat weight sensors) and thought it needed to activate something for safety. My big worry is if this happens when the car is locked, I’ll be stuck. I’ll let you know if I figure it out.
@Jessie
No aftermarket parts here—everything is stock. I bought it from the original owner about a year ago. I’ll check the service records to see when the last battery was replaced.
I think ACC might be turning on randomly when I’m not around, killing the battery. A few months ago, the car stayed on after I removed the key! I could shift gears and drive without the key in the ignition. This truck is definitely a weirdo, but I’m enjoying it. If it were my daily driver, I’d probably look for something else by now!
