Replaced battery/alternator, car has shut down. Help!

My neighbor (with 30 years of auto repair experience) and I replaced my battery and alternator two days ago. I had been having startup issues and we feel confident in our diagnosis. We got ACDelco parts from a major Ford service department (where my neighbor worked until his retirement a few weeks ago).

So: We replace the parts and my '01 Chevy Blazer starts up fine. I drove to work yesterday with no problem and drove home for lunch with no issue. When tried to start it to go back, all my dash lights came on and cut back off; the engine didn’t try to kick. Everything just died.

When I told neighbor this evening, he does a :smack:, “Your computer may need to be reset. It’s an anti-theft feature.” He says there is a process, which I now believe is called a drive cycle, we should have done. Now, though, my car won’t start at all.

I have a bad feeling I’m going to have to get this mother towed to my local Chevy dealership and get charged for two or three hours of labor resetting the computer, thus nullifying the money I saved by going DIY. I’m going to try to call my nearest Chevy dealer/parts department in the morning without much hope of a solution I can do myself. Is there anything that I can do with my car still in my parking spot or do I just need to call a tow? I appreciate any advice.

Have you checked the engine management fuse? On my Saturn, that also controls the dashlights. I have 2 fuse boxes and it was the one in the engine compartment. Mine blew while I was driving so the dash lights were an indication that a fuse had blown.

I can peek in the fuse boxes. Would that have made your car undrivable?

Is this the LS1 engine? When you try to start the car does the security light on the dash flash? If it does your problem is with the VATS system. (vehicle anti theft system). The VATS shuts off fuel to the engine. If you have a different key try it. Sometimes the resistor pellet in the key goes bad. If the key is the problem you should still be able to start the engine after waiting for 3-5 minutes.

Since you changed the alternator and battery due to charging problems the VATS relay may have been shorted out and needs replaced.

A friend of mine with a GM car has had the anti-theft feature lock her out before. All she had to do was call the dealer and they told her over the phone what to do and got it running again. There is some timing involved, if I remember correctly, so while it’s inconvenient (and a semi-stupid feature) you probably won’t have to have your car towed.

I found a mention of this pertaining to the Cavalier, but I haven’t seen a security light. I don’t remember actually seeing a Security light on the dash. Hopefully, FalconFinder the same will be true for me. Fingers crossed, and all that.


In my experience, an anti-theft issue would have shown up right away. Since it has started since the work was done, I’d be very surprised if any “reset” is needed.

It’s important to know in what way it won’t start, specifically whether it cranks normally or not. If it cranks properly (goes ruh-ruh-ruh when the key is turned is turned to “start,” several “ruhs” per second), typically it’s an ignition system or fuel system problem. If it doesn’t crank properly (no response, or single click, or slow cranking like one “ruh” per second), it’s a starting system problem. Your description leads me to believe it’s the latter.

Have you tried jump-starting with another vehicle’s battery? If it then cranks and starts, the problem is a faulty battery, discharged battery, or poor battery cable connections. This is the area I would investigate first.

To expand what Gary T said, if your car sounds like it turns over quicker but does not start that means something like the ignition is not drawing power and thus allows the engine to physically turn faster.

As to the fuse, my night time dash lights were tied to the engine computer. they went off at the same time the engine quit (at 4 am on the highway).

I have tried to jump start to no avail.

I think I see your problem.:slight_smile:

Try this. If the car cranks but does not start, leave the key in the “start” position for ten min. Try to start it then. The ten min. is the time it takes for the anti-thief to time out.

Okay, but the key question is what happens when you turn the key to “start?” Does it crank normally but not catch and run, or does it fail to crank (or crank very slowly)?

Gary’s good but he’s not a pyschic. you can’t type too much information about the problem.