70 horn relay wiring mystery - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 2Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 33 (permalink) Old Dec 13th, 19, 4:58 PM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
70 horn relay wiring mystery

Fellas, I'm a bit confused on the wiring for my horn relay.


Picked up a restored 70 Chevelle about 2 months ago. The PO claimed the horn worked after it was restored. It hasn't worked while in my possession. I've attached a picture of the relay. The blue arrow is the incoming wire from the horns (which are new and work when direct to 12v). The red arrow is for the ground wire coming from the steering column. I've haven't popped the horn button off yet, but everything looks fairly new. So, my question is about the 3 different red wires going to the two terminals. Does this wiring look right? I though hitting the horn just grounded the circuit, through the relay. I would only expect one red wire from the battery, and the wire from the steering wheel on the opposite terminal. This doesn't appear to be the case on my relay. The relay doesn't click at all, even with power on. So, does this mean a wiring issue at the relay, bad relay, or issue at the steering column? Seems pretty basic, but any ideas??


Additionally, from my research, the pink/black wire is the key buzzer, which also does not work. This may be unrelated (not installed, never worked, etc.) Would that be a factor in why the horn doesn't work?
Attached Thumbnails
Click image for larger version

Name:	IMG_4718ee.jpg
Views:	20
Size:	57.2 KB
ID:	610586  

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555
vtchopperdude is offline  
Sponsored Links
Advertisement
 
post #2 of 33 (permalink) Old Dec 13th, 19, 5:29 PM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,482
Re: 70 horn relay wiring mystery

Term #1 should be wired to the horns
Term #2 should be the ground wire fed from the horn button on the steering wheel
Term #3/5 Should have a bus bar between them and have 3 red wires, 1 from the battery, 1 from the alternator, and one to the bulkhead connector or fuse box.
Term #4 is the key minder

To test, measure 12 v at 3/5 terminal, ground 2 terminal to activate relay for the horns to blow. Ground terminal 4 to activate the key minder. If any of the above fails troubleshoot accordingly.

Your just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
post #3 of 33 (permalink) Old Dec 13th, 19, 6:34 PM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
Re: 70 horn relay wiring mystery

Thanks for input! So from you info, all the red wires (battery, alt, fuse box), are correct by being attached to the bus connector. But, the wire from the horn switch is also on the bus connector, which would be incorrect according to your info. So, the horn switch wire is in the wrong spot...? Did this blow the relay you think?

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555

Last edited by vtchopperdude; Dec 13th, 19 at 6:51 PM.
vtchopperdude is offline  
 
post #4 of 33 (permalink) Old Dec 13th, 19, 10:08 PM
Lifetime Premium Member
Bob
 
Join Date: Mar 2005
Location: Jeannette Pa. near pittsburgh
Posts: 8,529
Re: 70 horn relay wiring mystery

Something else to TEST. When I restored my 70 with power windows, I installed a new relay, OH SH!T the windows did not work, Used the OLD relay, WOW windows work.
I had to solder a wire from the base of the NEW relay to the metal cover, WHY? The old relay was 100% grounded, The new relay was not grounded.
After I soldered a wire from the tin cover to the base all is well.
I never expected the base was not grounded???????????
Bob


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
1970 SS LS-5/M-22 El Camino- Org. Owner-AACA 2016-Senior Grand National Winner---MCACN-GOLD-2013
1970 ( FRAUD) SS 468 Station Wagon - Driver.
Robinls5 is offline  
post #5 of 33 (permalink) Old Dec 13th, 19, 10:09 PM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 61,852
Garage
Re: 70 horn relay wiring mystery

The column horn button wire being on the hot bus bar would be a dead short if the horn button was pressed.
It would either blow the fusible link or burn the horn wire into.
DUTCH MAX HEADWORK likes this.

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
post #6 of 33 (permalink) Old Dec 13th, 19, 10:21 PM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,482
Re: 70 horn relay wiring mystery

Quote:
Originally Posted by vtchopperdude View Post
Thanks for input! So from you info, all the red wires (battery, alt, fuse box), are correct by being attached to the bus connector. But, the wire from the horn switch is also on the bus connector, which would be incorrect according to your info. So, the horn switch wire is in the wrong spot...? Did this blow the relay you think?
Quote:
Originally Posted by Dean View Post
The column horn button wire being on the hot bus bar would be a dead short if the horn button was pressed.
It would either blow the fusible link or burn the horn wire into.
As Dean stated with the horn wire tied to 12v, when the horn button is activated there should have been sparks as its a dead short. I would say that lucky for you the horn circuit from the relay back to the horn switch has an open somewhere.

Your just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
post #7 of 33 (permalink) Old Dec 14th, 19, 10:19 AM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
Agreed that it is connected wrong. No sparks or anything when hitting the horn, so must be (hopefully) a blow fuse. Is that in the fuse block under the driver side dash or located elsewhere?

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555
vtchopperdude is offline  
post #8 of 33 (permalink) Old Dec 14th, 19, 11:35 AM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 61,852
Garage
Re: 70 horn relay wiring mystery

If like an original 70 the fusible link coming off of the positive battery cable is what feeds the bus bar. (Not much in the picture looks like original though)

Need to see if the bus bar has 12 volts and if the wire coming from the horn button is ground when the horn button is pressed.

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
post #9 of 33 (permalink) Old Dec 14th, 19, 11:35 AM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
Re: 70 horn relay wiring mystery

UPDATE: The large black wire is actually not the horn switch wire. I traced it over to the heater control unit, but it wasn't plugged into anything. So, I'm not sure why it's there. But, I did find the horn switch wire. It was tucked away, and I plugged it in, and BOOM, the horns are blaring. So, that tells me that something is completing the circuit elsewhere. Again, the horn button on the steering wheel looks fairly new, and is not stuck. Could the wires get easily pinched or crossed under the button? I'm going to go attempt to pull it off right now. However, it looks like the horn switch wire was deliberately tucked away. It doesn't look as if it just fell off the contact. I wonder if when they were restoring it they had this same problem with them continuously blaring and couldn't figure out where it was grounding...???

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555
vtchopperdude is offline  
post #10 of 33 (permalink) Old Dec 14th, 19, 11:39 AM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
Re: 70 horn relay wiring mystery

Before I got pulling this horn button off and tearing something up, what would my issue be here?? The plunger/spring mechanism is too long and continuously making contact under the horn button?

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555
vtchopperdude is offline  
post #11 of 33 (permalink) Old Dec 14th, 19, 11:42 AM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 61,852
Garage
Re: 70 horn relay wiring mystery

So the "horn switch" wire is grounded without the horn button being pressed then?

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
post #12 of 33 (permalink) Old Dec 14th, 19, 11:54 AM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
Re: 70 horn relay wiring mystery

Quote:
Originally Posted by Dean View Post
So the "horn switch" wire is grounded without the horn button being pressed then?

Yes. When I take the horn switch wire and plug it into the relay, the horns continuously go off. The steering wheel horn button is not stuck. I wonder if there was an installation error. I did some more digging, and I found a post about trimming the horn button contact pin. If that pin is not trimmed, would this cause the circuit to always be complete and horns continuously blaring?

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555
vtchopperdude is offline  
post #13 of 33 (permalink) Old Dec 14th, 19, 12:10 PM
Lifetime Premium Member
Randy
 
Join Date: Aug 2008
Location: Central Alabama
Posts: 4,318
Re: 70 horn relay wiring mystery

Quote:
Originally Posted by vtchopperdude View Post
Yes. When I take the horn switch wire and plug it into the relay, the horns continuously go off. The steering wheel horn button is not stuck. I wonder if there was an installation error. I did some more digging, and I found a post about trimming the horn button contact pin. If that pin is not trimmed, would this cause the circuit to always be complete and horns continuously blaring?
Pull your horn button off and plug back into the relay. If the horns don't blow, then your problem is at the horn contact on the steering wheel. If they do blow, then the horn wire is pinched somewhere to ground.

Randy
TC # 5401
67 Project SS Clone

Owning a Chevelle project is like having a giant-size piggy bank that you keep pouring money into....but you can't get it back out.
pnugene is offline  
post #14 of 33 (permalink) Old Dec 14th, 19, 12:23 PM Thread Starter
Tech Team
Adam
 
Join Date: Nov 2019
Location: Valdosta, GA
Posts: 118
Garage
Is there a trick to pulling the horn button off?? I don’t want to pry on it too hard.

1970 Chevelle 454, 4 spd Muncie, 12 bolt, 3.31, AC, PS, PB, Ridler 695, Nitto 555
vtchopperdude is offline  
post #15 of 33 (permalink) Old Dec 14th, 19, 12:30 PM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 61,852
Garage
Re: 70 horn relay wiring mystery

Post a picture of the steering wheel

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome