Adding a Second Horn

[APK]

My 1972 Dodge Dart Swinger only has a Low-Note horn. I picked up an High-Note from a 72 Dodge Dart off of ebay. My Dart has two connectors one on the current horn and one for a second.

Well if I only hook one at a time up they work, if I hook both up I only hear the relay clicking.

Ideas?

 

[cudajim]

You probably have a bad horn relay. The internal points/switch most likely has a bad spot on it giving you a resistive connection.

 

[trapster]

Take the can off of the horn relay and clean the points with fine grain sand paper.

If this does not work by a new one.

 

[APK]

The horn I got from ebay has undercoating on it so I am strippng the off. Is there any type of black paint I should use to repaint it?

 

[trapster]

I just used gloss black enamel

 

[805moparkid]

or the other horn is shorted out...

this happened to me and almost lost my dart to an electrical fire...

test your known good horn... then try the other by its self... if it works then yes you probably have a relay problem...

but if it dosn't then that horn is shorted and will end badly...

 

[APK]

test your known good horn... then try the other by its self... if it works then yes you probably have a relay problem...

From my inital post.

if I only hook one at a time up they work, if I hook both up I only hear the relay clicking.

 

[805moparkid]

From my inital post.

lol ah duh...
:sign3:

 

[APK]

I just used gloss black enamel

Ready to paint. Any particular brand?

 

[mopardude318]

Ready to paint. Any particular brand?

i like rustoleum paint. takes longer to dry but pretty durable.

 

[67Dart273]

You could have one horn drawing exessive current. Try adjusting it. "Rig" a clip lead so you can jumper the relay coil out at the horns

The horn wiring in these cars is a little flaky. For one thing, the relay is FAR from the horns --- the wiring is not very big --- and the main high current horn power MUST PASS through the bulkhead connector, so IT can be a problem as well

Rig your voltmeter at the horns and measure voltage while honking them

IF the voltage seems low, move back to the bulkhead connector. WARNING I just looked at the 72 shop manual download, and there is a MISTAKE as to which connector the horn wire (should be dark green/ red) goes through the bulkhead

Check voltage on both sides of the bulkhead

I assume the relay plugs into the fuse box? Maybe not. You need to try to get right to the relay, and check battery voltage in "when honking" against horn voltage out. Diagram shows battery supply to the relay as H1-16V (no 16 violet goes to in harness splice)

From the relay out through the bulkhead to the horns as H2-16DGN/R (no 16 dark green / red) but the bulkhead feed is ambiguous

The "My Mopar diagrams show thus:

http://www.mymopar.com/downloads/1972/72DartA.JPG

http://www.mymopar.com/downloads/1972/72DartB.JPG

THEY ARE ALSO WRONG. They show the horn wire going to "L" in the bulkhead, which inside the car is the YELLOW start wire.

The "inside" bulkhead connector shows "T" at the bulkhead. So the start and horn wire goes to either L or T, you'll have to find out. The 74 diagram shows it going to T so I would tend to believe that.

Below are the 74 Dart diagrams which I believe correctly showing the horn wire going to "T" in the bulkhead:

http://www.mymopar.com/downloads/1974/74DartA.jpg

http://www.mymopar.com/downloads/1974/74DartB.jpg

Below are some screenshots from the 72 shop manual:

Below, you see the horns 16dgn/r going to "L" at the bulkhead. I BELIEVE this should be "T"

Below, we see the INTERIOR bulkhead, and it shows "L" being the S2-Y which is the START wire

It shows "T" being H2-16DGN/R which is horns

Below, the horn relay/ buzzer. Top right is H3-20BK which goes to the horn button. GROUND that terminal to actuate the relay

Bottom right is G2-16DGN/R which goes through the bulkhead to the horns

Left center (B) H1-16V is battery power TO the relay which comes form the "in harness splice." THIS IS NOT FUSED

 

[416stroker]

Make sure the added horn has a good clean mounting surface and is grounded good. I had the same problem when I added the second horn to my Dart. The low note would work by itself but not when I plugged in the hi note horn. After a lot of dinkin around and adjusting and switching one for the other, I found that the mounting surface of the second horn wasn't as free of paint as the low note was. Cleaned the surface real good and wahlah...they both worked together and haven't had an issue since.

That may not be your issue, but it ended up being the case in my situation.

 

[APK]

I have replaced the buzzer horn relay. I have performed a test by connecting the high note horn to a ground and tested with both horsn successfully. I will protect the bolt hole on the mounting bracket from paint to establish my ground.