My 1983 Mercury Grand Marquis LS 2-Door

[87gtVIC]

Matt. You can always add a relay to the existing circuit to take the load off of the stalk switch. Doing so may even get some more voltage to the new horns increasing their sound.

[packman]

Very nice car; sounds mean too! If you want to clean up the exhaust you can try aviation/hose clamps instead of the larger exhaust clamps. I used them to clean the rear of the exhaust on my mom's CV.


Packman

[MattsLincoln]

Matt. You can always add a relay to the existing circuit to take the load off of the stalk switch. Doing so may even get some more voltage to the new horns increasing their sound.

i would have to know what wires go to where. it does have a good amount of load on it. everytime i blow them the lights dim.

[87gtVIC]

okay this is easy. Since you added these new horns to the system you can snip the stock wire you tapped into and put the stock wire into pin 86, put a ground on pin 85..put constant battery power on pin 30 and reconnect the the wires leading to the horn on pin 87.

So in sum

30=Battery power
87=Wire leading to horns
86=Stock wire out of switch originally leading to horns
85=Ground

[MattsLincoln]

wheres a good ground spot. Also one of the stock horns has two wires coming out one goes from the switch and the other connects to the other stock horn. Can i simply use the wire from that horn that goes to the other stock horn as 87. 86 was going to be the wire on that horn that runs to the switch. Ground i may screw to the negative terminal of the battery and the battery power i would screw into the positive of the battery.


note: the relay i am using has 5 contacts i guess i dont connect anything to that one not mentioned right.

[87gtVIC]

Hmm Let me see how should I say this...You mentioned that your horns are grounded through their mounting locations...so the wires looping between them would be the power wire (signal...w/e). You want to intercept the wires leading to the horns before they reach it in order to ensure you supply fully battery power to them through the relay. Cut the existing wire leading to the horns a few feet back (or w/e) as you just want to make sure you are supplying full power to the horns by connecting that wire to pin 87. The wire that is still connected to the horns goes to pin 87 and the wire that is supplying power through the stalk switch goes to pin 86 to trigger the relay. 85 gets grounded. 85 and 86 make up the coil within the relay. when power is supplied to the coil pin 30 is connected to pin 87 giving the direct battery power from pin 30 to pin 87. When power is removed from pin 86 (releasing the horn switch) pin 30 and pin 87 is no longer in contact.

[sly]

and of course... fuse the wire from the battery to the relay.

[85crownHPP]

note: the relay i am using has 5 contacts i guess i dont connect anything to that one not mentioned right.

Right. You have a double throw relay, which can be used just like a single throw when wired like one. Fun with double throw comes in the next lesson, if you make it.

[1987cp]

Right. You have a double throw relay, which can be used just like a single throw when wired like one. Fun with double throw comes in the next lesson, if you make it.

Do you have a SPDT running your electric fan like on my electric fan install? That'd be a practical lesson. Actually, I have a couple of videos posted somewhere ......

[MattsLincoln]

ok i hooked up the relay and pressed the horn and bam released the switch and the horns were blowing non stop i had to disconnect the wires from the relay to stop it. what happened and whats wrong. man i have a earache was so fuckin loud.

[sly]

what was the relay rated (amps)? You may have welded the relay shut on the first shot. I'd go for a 30-40 amp relay at least. If the one you used was a 30 amp... try a 40.

also, double check your wiring.

Here's a diagram of what should be happening... treat the "air horn compressor" as your additional horns.

[MattsLincoln]

i dont understand that. damn i hate electrical diagrams. hang on let me upload a diagram of what i did.

[87gtVIC]

Yes it is a little confusing. Your diagram should help out though.

[MattsLincoln]

ok read this

[sly]

ok... 85 and 86 are essentially interchangeable. It just needs current flow. One of them needs to be ground... the other needs to be the line from the stock horn switch.

87 however should be connected to the wire that goes to the stock horns... not just one of them at the horn itself. The horn switch wire needs to be cut and the one from the switch itself goes to 86 on your diagram while the other half of the cut that goes to the horns should be on 87. Your power and grounds are fine as far as I can tell.