Okay guys so I have used the search button on several occasions and I can't seem to find what I am looking for. I need to know how to bypass the stock horn relay using a universal 4 pin relay. An old post by Icemark made reference to using a 4 pin relay but didn't explain it in detail. I know that I could re solder the contacts for the stock horn relay in the CPU but I want to bypass it anyway for reliability reasons.

As I understand it I should do the following:
-Splice into the Green / Orange wire coming from the steering column to pin 86
-Splice into the Green / Red wire at the CPU to pin 87
-Splice into the Green / White wire at the CPU to pin 30*
-Run a wire from pin 85 to ground

*As for the Green / White wire I believe there are 2 at the CPU with one being thicker than the other. Which one should I use?

Does this sound like it will work? Please advise as I am far from electrically inclined. Thanks in advance for any help you can give me guys. An intermittent horn is a really annoying problem to have as I'm sure many of you know.

 

The G/W for the HORN gets pwr from the STOP fuse.

The G/W for the other wire (courtesy lights etc), gets it's pwr from the ROOM fuse.

So you now can with a meter, figure out which of the two G/W is for the HORN by checking for pwr on a G/W wire and pulling either the STOP or ROOM fuse to know what that particular wire is dedicated to.

 

When my horn was acting up, I had gone through 3 CPU's, and none worked. It turned out to be the power wire coming into the CPU. Being very hard to work in that area, I found my horn wire coming into the cpu harness, and took it out. I then added a long length of wire to it and ran it into the front of my engine bay and put the relay there. The horn wire grounds out the CPU relays internally, so I used it the same to ground out the new relay. Then I wired some power from the battery, and ran new wires to the horn. Voila, beep beep!

 

Thanks for the replies. I'll wire it up today and let you guys know if it works.

 

After a long morning under the dash I still can't seem to bypass the stock horn relay in the CPU. I determined that the thicker of the Green / White wires is the one I want to use for pin 30 on the external relay but it still doesn't seem to work.

I cut the Green / Orange wire at the CPU and ran it to pin 86
I cut the Green / Red wire at the CPU and ran it to pin 87
I tapped into the Green / White wire at the CPU and ran a wire to pin 30
I ran a wire from pin 85 to the body and bolted it down

Still nothing. Is there something I'm missing? In the stock wire configuration the horn works intermittently so I know it's the horn relay in the CPU and for that reason I'm trying to bypass it but this is turning out to be a real headache.

 

When you touch the green/white wire to the green/red wire the horn should honk. Does it?

The new relay has a coil. One side of that coil should get the green/white wire. The other side of that coil should get the input from the push button on the steering wheel. That would be the green/orange wire.

Push the horn button and now the relay pulls in. So one of the contacts in the relay should get a input from the green/white wire. You splice a wire off the green/white to it. The other contact in the new relay gets the green/red wire that goes to the horn. If you push the horn button the relay pulls in and the contacts come together and the horn honks.

So I'm asking you to touch the green/white wire to the green/red to make sure there is a circuit to the horns ........or not.

If the horns honk, then the problem probably lies in the horn button not putting a ground on the green/orange wire to cause the new relay to pull in. So if the horn did honk with green/white touching green/red.......................I'd put a meter on the green/orange and put the meter on ohms and push the horn button. You should see the meter go from open to 0.2 ohm give or take.

OR with all the wires to the relay as you described earlier, just get a spare piece of wire and put one end of it to a known gnd and the other end to where the green/orange attaches to the new relay. Relay should pull in and horn honks.

Sorry, I don't deal with relays labled like your talking about normally so I can't say if it's wired right or wrong to the relay. I've some relays laying around labled like that but I'd have to get off my butt to go find 'em. Ain't happening.

EDIT: I looked online. The 85 and 86 are the coil of the relay. So green/white to one of those and green/ornage to the other. Then green/red to 30 or 87 matters not which and the spliced green/white to the one that's left over.

http://www.bcae1.com/relays.htm

 

OK. I just reread you post above my last post. You wired it wrong. Follow what I suggested in the post above and all will be fine and dandy and money will grow on trees and there will be peace on earth.......

85.........green/white

86......green/orange

30......green/red

87.........spliced to green/white


85 and 86..........coil. One has pwr and the other gets a gnd from you pushing the horn button. Relay pulls in............contacts on 30 and 87 come together and pass power from the spliced green/white to the green/red and the horn honks reallll guuuuuud. Done

 

You're the man Hailers! Quick question though; 85 and 87 both "T" into the stock G/W wire? Thanks a million man.

 

just repair the CPU...while you're in there take your time and resolder as much as you have the patience to do. it will last if you do a decent job, and it will prevent future problems.
i've done it to 3 different logicons IN the car because i couldn't get to the cable connector due to the genius placement of it.. you should be able to do 1 cpu removed sitting comfortably at a desk :P

 

Yeah. The 85 and the 87 both get power from the green/white wire.

 

I plan to do both. Thanks again Hailers!

 

My horn now works perfectly with the new external 4 pin relay. All the credit goes to Hailers. I wired it exactly as he suggested:

85.........green/white

86......green/orange

30......green/red

87.........spliced to green/white

This should be archived.