debosaur

Howdy

I have an 03 Tahoe 5.3 2wd. Has been a great vehicle thusfar. Yesterday I drove from Texas to Colorado with no issues. Today, I was driving on a dirt road that was recently graded, washboard style. It was terrible.

After quite a while, The dash started beeping, and I see a warning saying "reduced engine power" and then "service brake system" and then the truck was dead - heard a noise for a few seconds that was a bit like humming from behind the brake pedal/firewall. Checked under the hood and quickly noticed that the negative battery cable (side post) was incredibly loose, and the positive was a little loose.

After re-tightening them both, I did not have the voltage to start the truck. I tried to get a jump to no avail. The truck doesn't turn over at all. After the attempt, the daytime running lights were on, despite the key not being in the ignition. Under the hood was an electrical buzzing sound, which may have just been the DR lights... The fuel gauge showed empty, and the oil pressure gauge was not functional either. The voltage gauge was working. Also the security light and seat belt light were constantly illuminated.The cd changer kept shuffling, and the dome / entry lights were all lit until there was just nothing left in the battery. When turning the key, the dash lights, radio, pretty much everything goes dark. Turning the key back to the on position reactivates these lights.

When trying to start the truck there was no clicking, but occasionally there would be a loud click, similar to the sound of old school turn signals that would go about 5 times then quit. This was independent of trying to start the truck, as in I was not turning the key at this time.

I was towed back home, and now get to try and make some sense of all this.

I know that a dead/dying battery can cause some weird side effects, but I'm concerned that it didn't jump off.

I was hoping I could get some suggestions as to where to start on this whole thing. I assume it is entirely possible that I may have blown some fuses, but I'm hoping I didn't short something out? I'd really love it if I could get out of this by getting a new battery, but I have my worries.

Thanks for taking the time to read this, and I would really appreciate any information that could be sent my way.

Deebs

73shark

Welcome to the forum.

I'd put a full charge on the battery.

debosaur

73,

Just went and had the battery tested and charged at AZ. Came back and threw it back under the hood, but no luck. The dash still goes dark when I turn the key, and comes back when I release back to the on position. All electronics work as far as I can tell, except for the fuel and oil pressure gauges. Occasionally, the low fuel light will come on, but it's got a full tank.

Also I noticed the key fob will not activate the door locks.

Do you have any idea of where I should look next? Perhaps the fuse box? I'm hoping I didn't short something out in the starter....

73shark

Try disconnecting the battery for 10 minutes and then reconnecting it.

It's possible that the loose connections on the battery could have created some voltage spikes that took out some of the electronics.

debosaur

Thanks,
I've got it disconnected now, and will hook it back up in the morning to test. I'm not terribly hopeful, but we will see.

debosaur

Ok I had someone come out and take a look, and the initial theory was the ignition switch, as it was getting 12v in but only 5v out. Switched it all out and no progress. Computer has power but is unable to communicate with the scanning tool he had. Also the ignition would not release the key unless we removed the switch completely, which seems really off...

So in short, I now know it's not the ignition switch, or -- the computer AND the ignition switch are bad.

I was told that a pcm would cost over 1.5k to replace, is this true?