Will codes from Sims 3 packs still work?

What kind of DLC packs do you mean ? Expansion packs ? Stuff Packs ?Store Worlds ? Store content ?

they are expansion packs and stuff packs, and one world pack

For installing the expansion/stuff packs, the codes should still work if you're asked during installation. There's no need to activate them again though since the game should already be in your account. 

Download the Origin client here: http://origin.com/download then login with your account and the games should be in myGames.

The Store world should be here. https://store.thesims3.com/purchaseHistory.html

But I dont have all of my stuff except for 3 things: 2 maps, and the date night exclusive.  So Do I have to reinstall the expansion/stuff packs and the codes still works? I'm manking sure that i will have to do that. 

If the expansions/stuff packs are no longer on your Origin account, you need to contact a game advisor

Game advisors can be found through live chat.

1. https://help.ea.com/en/contact-us/ 
2. Click on the orange NEXT button
3. Select a platform
4. Click on the orange NEXT button
5. Select a topic and describe your problem in a few words
6. Click on the orange NEXT button
7. Click Chat Now to chat with a Game Advisor
   

In Details here: How to contact a Game Advisor using the new EA Help page