The Saturn Astra is known for having a horn that leaves something to be desired. When a tractor trailer is weaving into your lane on the interstate, you don't want to politely say, "Excuse me. Would you please stay in your lane?" You want to scream, "Get out of my lane, psycho!"
So, I went about scouring the web for resources concerning this problem. I came up dry. The few posts that I did find concerning this problem only mentioned that no one liked the stock horn. I did run into a few forums with people claiming to have switched their horn, but they gave no instruction as to how to do it.
Step 1: Step 1: Locating the Horn
First, walk up to the front passenger side of the Astra. In the picture, I have a ratchet pointing directly at the horn.
In this step, you will not need any tools.
Step 2: Step 2: Identify the Horn
You should put your head right next to the passenger-side front tire, and then you should look up. You will see the 3-inch round horn, with a wiring harness connected to it.
In this step, you will still not need any tools.
Step 3: Step 3: Disconnect the Wiring Harness
Reach behind the connector, and push the tab away from the wiring harness. If you are successful, the wiring harness should slip out of the horn.
You will need thumbs to perform this operation.
Step 4: Step 4/4a: Remove the Horn and Bracket.
4. Using a 13mm ratchet, loosen the nut that holds the horn and bracket onto the car. Once that is loosened, you should be able to pull the entire assembly out and away from the vehicle.
4a. Using a 10mm ratchet, loosen and then remove the nut that holds the horn to the bracket.
Step 5: Step 5: Mounting the Horn to the Bracket
You should have a new horn from your local auto parts store. Using the nut provided from the new horn (or the original nut, if it fits), mount the new horn to the horn bracket.
You will need a 10mm ratchet for this step.
Take the newly assembled horn/bracket combo, and set it to the side, as it will be in the way for the next step.
Step 6: Step 6: Locating the Wires
Using a *sharp* knife, cut the cloth-like wire loom. Make sure that you do not cut the wires, or yourself. A sharper knife will help control the blade, making the cut easier. You should be able to pull the plastic wire loom down and away from the two wires.
You should be looking at 2 wires at this point: one brown, and the other brown/white.
Step 7: Step 7: Disconnect the Battery
This is critical when working on anything electronic. You do not want to shock yourself, and you certainly don't want to deafen yourself when you hook up just one wire to your new horn.
You do not have to pull both terminals. Pulling just the negative is plenty.
Step 8: Step 8: Cut the Wiring Harness
This is the scary part. There have been horror stories of OnStar malfunctions, airbag deployment, etc. etc. etc. However, as this is only a two-wire system, there is no other control or problem to run into.
Using wire snips, cut approximately 1-inch under the wiring harness.
"Strip" the wires using a wire stripper or a sharp knife. If you choose to use the later, be careful. You can cut yourself pretty badly.
Step 9: Step 9: Affix the New Connectors to the Wires
Using wire crimps, crimp the new horn connectors on your newly stripped wires.
Try to twist the connectors. You can tell if the crimp is good if you can not twist the connectors around on the wire.
Step 10: Step 10: Mount Your New Horn and Bracket to the Car
Using the 13mm nut from the Step 4, re-attach the mounting bracket to the vehicle. Only hand-tighten the nut, as it can be difficult to pull on/off.
Attach the wires to the new horn.
Re-attach the negative battery terminal.
Test your new, AWESOME horn.
If it doesn't work, it is likely a connection problem. Once you have worked that out, tighten the 13mm nut all the way down, and you are DONE!
Now, instead of sounding like you are a moped in heat, you will command the road with a strong tone and much louder sound!