Electrical Relays...

dogboy2 · 08-09-05, 04:54 PM

With the help of some good people on this site (lovetoski), I've been trying to hook up some aftermarket horns to the '60.

Question: are all relays created equal or are they function specific, i.e. horn relay, flasher relay, headlight relay, etc., with different operational requirements?

Thanks,
-dogboy- '87 FJ60

wingysataday · 08-09-05, 05:10 PM

usually the relays come with the horn if you get a super loud one.

Ming89FJ62 · 08-09-05, 05:28 PM

Any 12 VDC, 20 amp relay should be fine. Buy one w/ both N/O (normally open) and N/C (normally closed) contacts so you have choice on how the circuit sets up. Any parts store should have one (NAPA, AutoZone etc.)

RoddQLD · 08-09-05, 05:42 PM

Except for the flasher relay (if you're refering to the indicator/blinker relay).
No good if you want to 'bbbaaaAAARRRrrrpp' and you only get a 'beep beep'!!! lol

lovetoski · 08-09-05, 10:41 PM

Quote:

Originally Posted by Ming89FJ62

Any 12 VDC, 20 amp relay should be fine. Buy one w/ both N/O (normally open) and N/C (normally closed) contacts so you have choice on how the circuit sets up. Any parts store should have one (NAPA, AutoZone etc.)

Pete - might be that this is the diff between a "horn" relay and the "normal" one that you've got? Gotta think on it for awhile...

import silvia · 08-10-05, 01:22 PM

Well once we get past the fact that there are bosch relays and then crappy ones that will need replaced, yes all relays are pretty much the same.

Energize termials 85 and 86 (polarity not important) and 30 is switched to terminal 87, with 87a being open. Remove power from 85/86 and 30 is switched to 87a with 87 open.

Spook50 · 08-10-05, 01:48 PM

Quote:

Originally Posted by import silvia

Well once we get past the fact that there are bosch relays and then crappy ones that will need replaced, yes all relays are pretty much the same.

I used Tycho relays for my headlight harness and haven't had a problem with 'em yet. I'm not sure if they're really better than Bosch, but so far so good. I really should order some spares though...

dogboy2 · 08-10-05, 06:36 PM

Quote:

Originally Posted by lovetoski

Pete - might be that this is the diff between a "horn" relay and the "normal" one that you've got? Gotta think on it for awhile...

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-

import silvia · 08-11-05, 10:54 AM

Dog,
Automotive relays are quite standardized. Go to the local parts store and purchase a Bosch 30A SPDT relay. Then wire the new horn following the supplied instructions. Keep in mind that the LC horn uses a switched ground to work (on the 2 wire connector one side is constant 12v+ and the other side is switched negative).

dogboy2 · 08-11-05, 11:59 AM

Quote:

Originally Posted by import silvia

Dog,
Automotive relays are quite standardized. Go to the local parts store and purchase a Bosch 30A SPDT relay. Then wire the new horn following the supplied instructions. Keep in mind that the LC horn uses a switched ground to work (on the 2 wire connector one side is constant 12v+ and the other side is switched negative).

importsilvia,
Thanks for all of the input re: wiring the aftermarket horns. The problem I am having with the relay I've wired up is that both wires, G & G/O, on the OEM horn wiring are "hot". As per the FSM wiring diagram, the G/O wire is a constant "hot" and the G wire is switched at the steering wheel. I tapped into the G wire for use as my "signal/switch" wire for my relay.

Problem is that when both new horns on the new custom circuit (or the OEM ones on the factory wiring) are connected, the G wire becomes "hot". It doesn't show current on a test lamp when one of the OEM horns is disconnected from the OEM harness, only the G/O wire does. However, once the circuit is completed by connecting the second horn, this wire becomes "hot". Consequently my relay is receiving a constant "hot" signal causing the horns to sound continuously independent of the horn switches on the steering wheel.

If this is of any help, I tapped into the G wire on the passenger side of the truck as it made for a shorter run for the battery lead but in my electrical naivety, don't think this should matter, right?

-dogboy- '87 FJ60

import silvia · 08-11-05, 12:17 PM

OK, I wasn't sure if the 60 and 62 were 100% the same in this regards but it sounds like. According to the FSM what is the amperage of the fuse on the G/O lead?

dogboy2 · 08-12-05, 05:13 AM

Quote:

Originally Posted by import silvia

OK, I wasn't sure if the 60 and 62 were 100% the same in this regards but it sounds like. According to the FSM what is the amperage of the fuse on the G/O lead?

import silvia,

the OEM horn circuit is protected by a 15 amp fuse at the fuse block.

looking more closely at the FSM wiring diagram, it appears that in order for the relay I purchased to work in conjunction with the horn buttons on the steering wheel, I would have to run the "signal/switch" wire from the relay all the way up through the steering column and tap it into the button wiring which seems silly and a giant PITA.

that's what prompted this post: lovetoski is running the same aftermarket horns on his '60 and after talking with him, we've determined that I've wired mine in similarly, albeit on the passenger side vs. the driver's, with the primary difference being that he used an aftermarket relay specifically designated as a "horn relay" as compared to my "all purpose/general relay".

bottom line: his work when the horn buttons are depressed and mine sound continuously -- different relays? different end results?

-dogboy- '87 FJ60

Ming89FJ62 · 08-12-05, 07:30 AM

Not so - just wire the relay in as a replacment for the OEM horns using the existing wiring harness. When you complete the ground by pressing the horn on the steering wheel you'll close the contacts on the relay. Use the N/O contacts to activate the new horns. The circuit sets up just like adding fog lights.

Harry

import silvia · 08-12-05, 11:15 AM

How many amps is the recomended fuse for the aftermarket horn? A 15 amp circuit is capable of supporting 180 amps at 12 volts, which is quite a bit and I would bet more than enough to sound anything short of those lame ass train horns that idiots are putting on cars.

dfmorse · 08-12-05, 12:29 PM

A 15 amp fuse that's capable of holding 180 amps is called a piece of silver rod. The wires would go poof in no time at all...

import silvia · 08-12-05, 01:27 PM

Quote:

Originally Posted by dfmorse

A 15 amp fuse that's capable of holding 180 amps is called a piece of silver rod. The wires would go poof in no time at all...

Oh yeah, I meant watts not amps. My bad.

dogboy2 · 08-12-05, 03:38 PM

Quote:

Originally Posted by import silvia

Dog,
Automotive relays are quite standardized. Go to the local parts store and purchase a Bosch 30A SPDT relay. Then wire the new horn following the supplied instructions. Keep in mind that the LC horn uses a switched ground to work (on the 2 wire connector one side is constant 12v+ and the other side is switched negative).

import silvia,

that is a SWEET link to a great site

very nice, thank you...

-dogboy- '87 FJ60

dogboy2 · 08-16-05, 12:14 AM

Quote:

Originally Posted by Ming89FJ62

Not so - just wire the relay in as a replacment for the OEM horns using the existing wiring harness. When you complete the ground by pressing the horn on the steering wheel you'll close the contacts on the relay. Use the N/O contacts to activate the new horns. The circuit sets up just like adding fog lights.

Harry

Hey Harry,

Just drew up this wiring diagram based on your post above: is this what you are talking about?

Thanks,
-dogboy- '87 FJ60

import silvia · 08-16-05, 09:35 AM

You need a fuse on the R+ line from the battery. But I still think the horn relay should not be needed since the OEM circuit is 15 amps.

dogboy2 · 08-16-05, 10:38 AM

Quote:

Originally Posted by import silvia

You need a fuse on the R+ line from the battery. But I still think the horn relay should not be needed since the OEM circuit is 15 amps.

Good point: I forgot the in-line fuse on the wiring diagram but did include one on the actual harness I fabricated. Both Fiamm horns are rated at 5 amps each, so I put a 10 amp fuse in-line with the battery on the R+ line.

I had hoped to be able to just "plug & play" the new horns but unfortunately the Fiamm horns draw more amps than the OEM horns and subsequently, will not sound with a direct connection to the OEM horn wiring, hence the relay.

If I hook one, new Fiamm horn up the OEM horn wiring and leave one OEM horn connected, I can get both the OEM and Fiamm horn to sound. If I hook both Fiamm horns up to the OEM horn wiring, replacing the OEM horns in the factory location, neither Fiamm horn will sound. I only get a metallic "thud" sound.

If I wire a switch into the B line, the relay functions as switched positive and the Fiamm horns sound beautifully, albeit independently from the OEM wiring circuit and horn switches which defeats my purpose. (my custom harness works

)

If I run the B line directly to the horn switch contact on the steering wheel (between the switch and ground), the relay again functions as switched positive and the new Fiamm circuit works great. Problem with this is that I would have to run a long piece of wire from the front of the truck, through the firewall, dash, and steering column and then deal with the issue of a mangled wire with every turn of the steering wheel (enter the OEM horn contact ring and pickup that addresses this issue).

I understand how the OEM switched negative circuit works, and I understand how my custom switched positive circuit works. What I can't seem to make my thick skull comprehend is how to make my switched positive circuit work with the switched negative horn buttons of the OEM horn circuit.

I know I am very close to making this thing work as intended -- so close that it's KILLING me!!

My cretin brain needs some insight -- what am I missing here people?

-dogboy- '87 FJ60