2008 Tahoe acting funny

[Ken Dalton]

My first post.

I bought an 08 tahoe LTZ brand new and loved it, sold it for an explorer after 8 years. Had the explorer for 1 year and trans went out. They had to overhaul it and that bothered me. I sold that. I just bought a really clean 2008 white Tahoe LTZ (like my old one) for $16k. I already like it much better than the ford. I sure missed having a tahoe!

I replaced air filter, plugs, wires, and the 8 ignition modules. It runs perfect at 131k miles.

So I think it has a factory alarm. it has a small red light below the steering column and it honks when I lock and unlock despite me turning that off in the menu on the dash. My old tahoe didn't have this nor did it honk.

Today I went out to start the car and it just clicked. I turned the key again and nothing. The dash didn't even light up. It was 100% dead. Horn would not work, lights, nothing at all. Yet just 5 seconds ago it almost started. The only thing I could think of was to disconnect battery and reconnect it. (Battery has a full charge and it's an optima brand)

So I reconnected and now the tahoe is fine. The alarm went off (non stop honking) until I pressed unlock on the key fob but I've driven it, tried locking/unlocking 6 times. All is just fine.

Any idea why it would just go completely 100% dead? If it were an alarm issue I think the security light would've just came on. Not lose all power.

battery terminals looked ok. Simply disconnecting/connecting the battery fixed it.

Any ideas why or what I should check?

Also, I want to disable the factory alarm. We hate it and I think it's the cause of this issue. Any idea how to do that? Can the dealer do it or will it be $1000 ?

 

[PG01]

My first post.

I bought an 08 tahoe LTZ brand new and loved it, sold it for an explorer after 8 years. Had the explorer for 1 year and trans went out. They had to overhaul it and that bothered me. I sold that. I just bought a really clean 2008 white Tahoe LTZ (like my old one) for $16k. I already like it much better than the ford. I sure missed having a tahoe!

I replaced air filter, plugs, wires, and the 8 ignition modules. It runs perfect at 131k miles.

So I think it has a factory alarm. it has a small red light below the steering column and it honks when I lock and unlock despite me turning that off in the menu on the dash. My old tahoe didn't have this nor did it honk.

Today I went out to start the car and it just clicked. I turned the key again and nothing. The dash didn't even light up. It was 100% dead. Horn would not work, lights, nothing at all. Yet just 5 seconds ago it almost started. The only thing I could think of was to disconnect battery and reconnect it. (Battery has a full charge and it's an optima brand)

So I reconnected and now the tahoe is fine. The alarm went off (non stop honking) until I pressed unlock on the key fob but I've driven it, tried locking/unlocking 6 times. All is just fine.

Any idea why it would just go completely 100% dead? If it were an alarm issue I think the security light would've just came on. Not lose all power.

battery terminals looked ok. Simply disconnecting/connecting the battery fixed it.

Any ideas why or what I should check?

Also, I want to disable the factory alarm. We hate it and I think it's the cause of this issue. Any idea how to do that? Can the dealer do it or will it be $1000 ?

Could have been the neg term on battery, if its new maybe it wasnt fully tightened and you just happened to not noticed. I would get the name if alarm and google it to see how to disconnect it.

 

[Ken Dalton]

Could have been the neg term on battery, if its new maybe it wasnt fully tightened and you just happened to not noticed. I would get the name if alarm and google it to see how to disconnect it.

Both terminals were tight. It does seem like a negative terminal/grounding issue though.
I think it's a factory alarm.

 

[swathdiver]

Nobody is going to believe you're not still driving a Ford until you post up some pictures! Welcome aboard!

 

[Ken Dalton]

Nobody is going to believe you're not still driving a Ford until you post up some pictures! Welcome aboard!

Haha, we all make mistakes. Wife wanted something newer tech, bluetooth, etc. but smaller. The explorer had fancy stuff like AC seats that massage and adaptive cruise control. So we got it! Then we realized all of the things we hated about it. Glass hatch doesn't open, roof rack is useless, twin turbo gas guzzler, back seats were small and of course the trans blowing up after 13,000 miles. That was the kicker.

Currently we drive a Tesla Model S (amazing car) and a 08 Tahoe. We love both vehicles for different reasons. Hopefully this Tahoe doesn't give us problems though!

 

[Meccanoble]

There is a known/common issue with the negative wire going to battery. If you youtube, you will see a couple videos where they discuss similar symptoms on some gmc trucks. You may need to buy/repair ground wire going to battery.

 

[Ken Dalton]

There is a known/common issue with the negative wire going to battery. If you youtube, you will see a couple videos where they discuss similar symptoms on some gmc trucks. You may need to buy/repair ground wire going to battery.

Thanks, did some research and its exactly what happened. I just ordered a neg cable and should arrive saturday! hopefully it's not a big hassle to switch out. That #8 spark plug was enough of a hassle for me this week.