David 93 SL2m
05-13-2004, 11:12 AM
Okay, I am 95% sure this is how to do it... (Most of this is from memory and has been generalized from a few PMs I've received on this topic.) It is rather straightforward and I think I can describe it without a diagram.
The older S-Series have the horn between the headlights near the hood latch lever. The relay for the horn is in the fuse/relay box next to the battery under the hood. There are 2 wires going to the horn. Upgrading this type of horn is very easy.
However, the newer S-Series have the horn sort of under the driver's side headlight. The relay for the horn is on the horn itself. There are 3 wires going to the horn. Upgrading this type of horn can be done but is not quite as easy. The following applies to the newer type of horn with the 3 wires.
First, can you get the wire harness off the original horn? The wires will be wrapped in a loom and at the end is connector. You'll probably see this loom branching off a bigger loom that has the wires for the headlights and front parking lights near the driver's side headlight and then going sort of foward and down. It will probably need to be removed by pulling a small tab thing on the connector and pulling the connector at the same time.
If you can get that harness and connector off the original horn, you'll see it has 3 wires. There are two black wires and one that isn't black. It might be dark green but it is different and it is not black. If you look at the connector you'll see they are labeled A, B, and C.
A is the wire that is not black. It is "hot" all the time.
B is one of the black wires and it goes to the horn buttons on the steering wheel (which then go to ground to complete the circuit).
C is the other black wire and it goes to ground.
You want to connect the A wire that is not black to the positive connection on the new horn, and connect the B wire that is one of the black wires to the negative connection on the new horn. To connect the original wires to the new horn, you have a few choices. One, you can snip off the A and B wires from the connector, strip back some of the insulation of these two wires, and connect them to the horn - or connect them to new wires that will act as extension wires and in turn connect to the horn. Two, you can get some "taps" from Radio Shack that are designed for 18 to 22 gauge wire and some "male" 1/4 inch connectors. The taps sort of splice into the factory wires and then a male connector can slide into it. Of course you'd want to crimp or solder the male connector to a new wire for the positive connection to the horn and another one for the negative connection to the horn. Three, you can carefully scrape away enough of the insulation on the A and B wire near the connector and solder a new wire to each of them which will run to the positive and the negative connection of the new horn. Then cover up the exposed wire and solder with liquid electrical tape (or some other insulator).
Okay, now if you can't get wire harness off the original horn, first make sure that you can identify the loom with the three wires for the original horn. We want the one wire that is not black and one of the two wires that is black. But which one of the black wires? We need a circuit probe thing or a multimeter to see which wire is which. The one I have is real simple - it looks like a pen with a point at the bottom. At the top is a LED and a wire about 2 feet long and an alligator clip. I attach the alligator clip to a grounding point, carefully scrape back some of the insulation on the wire that I want to test, and touch the end of the probe thing to it. If the LED lights up then the wire is "hot." Okay, there are two black wires and we want to figure out which is which. One of them will go straight to ground all the time and the other will only go to ground when the horn buttons on the steering wheel are pressed (and this wire might be hot all the time too, I forget now). What we can do is connect that A wire that is not black to the new horn using one of the methods I wrote about above to the positive connection of the new horn. That part is certain. But which of the two black wires should we use? This is the exciting part! One of the two black wires will connect to the new horn's negative connection. The wrong wire will make the horn sound nonstop - that is the wrong wire. The right wire will only make the horn sound when the buttons on the steering wheel are pushed.
There is a very small chance that the original wires that we are tapping/splicing/using will not have enough current to power the new horn. If this is the case then we'll need to have those connections from the original horn go not to the new horn but rather to the coils of a new relay, and that new relay in turn will allow power to flow to the new horn.
If you need a new relay for your new horn, this new relay has 4 contacts (some have 5). Two of them will be for the coil and the other two of them will be for letting current flow to the new horn - or to the new horn's air compressor if it is an air horn. You want to take that wire from the original horn that goes to the steering wheel switch (a black wire) and connect it to one of the new relay's contacts for the coil. You'll need to connect a female connector to that wire so that it will slide on to the new relay's contact. You can choose either of the two coil contacts. Then the other coil contact needs to go to a grounding location. For this you can use the other black wire that went to the original horn. See, this is great - you need to connect the two black wires to the new relay's coil contacts and the order of the wires and the order on the relay's coil contacts don't matter!
At this point you can press the horn buttons on the steering wheel. You should hear the new relay click each time you press the horn buttons, and another click from the new relay when you release the horn button.
Now we need two wires to go to the other two contacts on the new relay. Again the order does not matter. One of them will go to a power source such as the battery and the other will go to the new horn or to the air compressor for the new horn if it is an air horn. If the new horn or air compressor has its two contacts labeled "+" and "-" then you want the wire from the new relay to go to the "+" contact on the new horn or air compressor. The other contact on the air compressor needs a wire to go to a grounding spot. Now everything is hooked up from an electrical perspective.
Now when you push the horn buttons on the steering wheel you should hear the new horn or feel air from the new air compressor. If you are attaching an air horn, then from here you just need to attach the tubes between the new air compressor and the new horns!
The best way to look at the electricity, wires, relays, buttons, and so on is to think of them as pipes or hoses carrying water - or trying to carry water. The water in the pipes is standing still except for when we push the button on the steering wheel.
If I made any mistakes, please point them out and make corrections here in this thread. Thanks!
The older S-Series have the horn between the headlights near the hood latch lever. The relay for the horn is in the fuse/relay box next to the battery under the hood. There are 2 wires going to the horn. Upgrading this type of horn is very easy.
However, the newer S-Series have the horn sort of under the driver's side headlight. The relay for the horn is on the horn itself. There are 3 wires going to the horn. Upgrading this type of horn can be done but is not quite as easy. The following applies to the newer type of horn with the 3 wires.
First, can you get the wire harness off the original horn? The wires will be wrapped in a loom and at the end is connector. You'll probably see this loom branching off a bigger loom that has the wires for the headlights and front parking lights near the driver's side headlight and then going sort of foward and down. It will probably need to be removed by pulling a small tab thing on the connector and pulling the connector at the same time.
If you can get that harness and connector off the original horn, you'll see it has 3 wires. There are two black wires and one that isn't black. It might be dark green but it is different and it is not black. If you look at the connector you'll see they are labeled A, B, and C.
A is the wire that is not black. It is "hot" all the time.
B is one of the black wires and it goes to the horn buttons on the steering wheel (which then go to ground to complete the circuit).
C is the other black wire and it goes to ground.
You want to connect the A wire that is not black to the positive connection on the new horn, and connect the B wire that is one of the black wires to the negative connection on the new horn. To connect the original wires to the new horn, you have a few choices. One, you can snip off the A and B wires from the connector, strip back some of the insulation of these two wires, and connect them to the horn - or connect them to new wires that will act as extension wires and in turn connect to the horn. Two, you can get some "taps" from Radio Shack that are designed for 18 to 22 gauge wire and some "male" 1/4 inch connectors. The taps sort of splice into the factory wires and then a male connector can slide into it. Of course you'd want to crimp or solder the male connector to a new wire for the positive connection to the horn and another one for the negative connection to the horn. Three, you can carefully scrape away enough of the insulation on the A and B wire near the connector and solder a new wire to each of them which will run to the positive and the negative connection of the new horn. Then cover up the exposed wire and solder with liquid electrical tape (or some other insulator).
Okay, now if you can't get wire harness off the original horn, first make sure that you can identify the loom with the three wires for the original horn. We want the one wire that is not black and one of the two wires that is black. But which one of the black wires? We need a circuit probe thing or a multimeter to see which wire is which. The one I have is real simple - it looks like a pen with a point at the bottom. At the top is a LED and a wire about 2 feet long and an alligator clip. I attach the alligator clip to a grounding point, carefully scrape back some of the insulation on the wire that I want to test, and touch the end of the probe thing to it. If the LED lights up then the wire is "hot." Okay, there are two black wires and we want to figure out which is which. One of them will go straight to ground all the time and the other will only go to ground when the horn buttons on the steering wheel are pressed (and this wire might be hot all the time too, I forget now). What we can do is connect that A wire that is not black to the new horn using one of the methods I wrote about above to the positive connection of the new horn. That part is certain. But which of the two black wires should we use? This is the exciting part! One of the two black wires will connect to the new horn's negative connection. The wrong wire will make the horn sound nonstop - that is the wrong wire. The right wire will only make the horn sound when the buttons on the steering wheel are pushed.
There is a very small chance that the original wires that we are tapping/splicing/using will not have enough current to power the new horn. If this is the case then we'll need to have those connections from the original horn go not to the new horn but rather to the coils of a new relay, and that new relay in turn will allow power to flow to the new horn.
If you need a new relay for your new horn, this new relay has 4 contacts (some have 5). Two of them will be for the coil and the other two of them will be for letting current flow to the new horn - or to the new horn's air compressor if it is an air horn. You want to take that wire from the original horn that goes to the steering wheel switch (a black wire) and connect it to one of the new relay's contacts for the coil. You'll need to connect a female connector to that wire so that it will slide on to the new relay's contact. You can choose either of the two coil contacts. Then the other coil contact needs to go to a grounding location. For this you can use the other black wire that went to the original horn. See, this is great - you need to connect the two black wires to the new relay's coil contacts and the order of the wires and the order on the relay's coil contacts don't matter!
At this point you can press the horn buttons on the steering wheel. You should hear the new relay click each time you press the horn buttons, and another click from the new relay when you release the horn button.
Now we need two wires to go to the other two contacts on the new relay. Again the order does not matter. One of them will go to a power source such as the battery and the other will go to the new horn or to the air compressor for the new horn if it is an air horn. If the new horn or air compressor has its two contacts labeled "+" and "-" then you want the wire from the new relay to go to the "+" contact on the new horn or air compressor. The other contact on the air compressor needs a wire to go to a grounding spot. Now everything is hooked up from an electrical perspective.
Now when you push the horn buttons on the steering wheel you should hear the new horn or feel air from the new air compressor. If you are attaching an air horn, then from here you just need to attach the tubes between the new air compressor and the new horns!
The best way to look at the electricity, wires, relays, buttons, and so on is to think of them as pipes or hoses carrying water - or trying to carry water. The water in the pipes is standing still except for when we push the button on the steering wheel.
If I made any mistakes, please point them out and make corrections here in this thread. Thanks!