Electrical Relays...

[Mike S]

Doug,
that's kind of where I'm leaning at the moment. Would make more sense but still don't know enough about how these things work to make a good call and have yet to find anyone with half a brain in any parts store around town who knows anything more than what the computer tells them to pull from inventory.

-db-

A relay is a switch that uses a low AMP circuit to open or close a higher AMP circuit. The circuit for the horn would be normally open, and close when you hit the horn and close the low AMP side of the circuit, which closes the switch and completes the high AMP circuit to the horn. Pretty simple really.

Get a good quality relay rated for the combined amperage of the horns, install according to directions, and forget it. It should last for years.

M

 

[import silvia]

Dog,
Wire your relay as follows:

1. fused (20amp) R+ to termial 85 and 30.
2. Line G to terminal 86.
3. Terminal 87 to the possitive terminals on your horns.
4. Ground the horns to the chassis ( I would just use the horn mounts for this)

When you hit the horn you will get noise. The fact that the stock 15 amp circuit cannot power the horns is a bit of a concern and could point to some needed electrical system maintenance. you may want to hunt around with a good schematic and a multimeter to diagnose the health of your system. I recently rebuilt my entire rear harness and found about 1.5 more volts at idle!

 

[Ming89FJ62]

Horn circuit

Dog,

Sorry - I just got back from a business trip. Follow what import silvia suggests - you need to use the N/O contact instead of the N/C contact.

Harry

 

[dogboy2]

We Have A Winner!!

Dog,
Wire your relay as follows:

1. fused (20amp) R+ to termial 85 and 30.
2. Line G to terminal 86.
3. Terminal 87 to the possitive terminals on your horns.
4. Ground the horns to the chassis ( I would just use the horn mounts for this)

When you hit the horn you will get noise.

import silvia, you are THE MAN!!
That was the ticket - I knew I was so f'in' close but in my electrical inexperience, didn't realize that the relay could be wired that way. ;p
I owe you one..... or two

Sometimes the obvious is the hardest to see, especially when you are too close to the matter at hand

For anyone else who has scratched their head over this one, posted below is a correct wiring diagram for wiring a device into a negative switched circuit.

Hope it is of some help,
-dogboy- '87 FJ60

 

[dogboy2]

not to forget the others who rolled up their sleeves and lent a hand during my time of need:

many thanks to lovetoski and Ming89FJ62 for taking the time to field my questions and share their knowledge -- I appreciate it.

now if you'll excuse me, I'm going to go blow my own horn(s) for a while -- hahahahahaha

-db-

 

[import silvia]

Glad it finally worked. And we now have the definative aftermarket horn wiring guide.

 

[dogboy2]

no doubt or any accessory component that needs to be relayed into a negative switched circuit.....

many thanks again,
-db-

 

[lovetoski]

dg - so glad you have horns...an epic to figure out for sure. Wierd though - and I really don't understand (yet) - that the positive from the battery goes to BOTH 30 and 85. AFAIK, 30 makes sense, but 85 is the ground. So, it's kinda like connecting + to the - which would (I think!!) make sparks.

Since it works, I obviously don't understand...

oh well...

 

[dogboy2]

dg - so glad you have horns...an epic to figure out for sure. Wierd though - and I really don't understand (yet) - that the positive from the battery goes to BOTH 30 and 85. AFAIK, 30 makes sense, but 85 is the ground. So, it's kinda like connecting + to the - which would (I think!!) make sparks.

Since it works, I obviously don't understand...

oh well...

In through the Out door -- it didn't make sense to me at first either until I understood how the pins in the relay are arranged and connected internally. Had to literally reverse my thinking after import silvia showed the way. Think linear pathways and positive constantly seeking ground and then the wiring diagram begins to make sense.

-db-