74 620 Horns are Wimpy - almost allowed an accident to occur

[Cardinal Grammeter]

I was in a line of cars and the one in front of me started backing up as if they didn't see me.  I was blowing my horn but even people in the parking lot didn't know I was blowing it.

 

When I got the truck, the horns didn't work, so I adjusted the screw to get the loudest sound.  However I don't know if there are other settings (resonant frequencies) that are louder - I set it at the first one I found.

 

It sounds like the pitch is correct, but they are VERY sort.

 

Some horn relays are "vibrators" instead of relays - I don't know which the 620 uses.

 

But I have to do something.  (haha, it's possible I have a set of Studebaker horns which look similar)

 

Frankly I'd like to get the loudest horns I could get.  Back (way, way, back) in the day, I'd look for some Cadillac horns.

 

Or maybe newer Nissan/Datsun horns?  720, Hardbody, etc. ???

[datzenmike]

I used a 6 volt VW horn back in the day. Man it's shrill with 12 volts through it.

[Cardinal Grammeter]

Might that be "teeth shattering" shrill???  (just what I'm looking for)

[ducky]

I wish my horns even worked. Got the truck, horns don't work. Replaced with an oem steering wheel, horns work. Next year, horns no longer work. Lame.

[Cardinal Grammeter]

Just now, ducky said:

I wish my horns even worked. Got the truck, horns don't work. Replaced with an oem steering wheel, horns work. Next year, horns no longer work. Lame.

 

The 620 had electrical switches that looked like they were designed by Edison (!)  Massive blocks of copper instead of tiny thin stamped parts - these switches should last 200 years.

 

THE PROBLEM is that the contact areas are so great that the contact force is insufficient to produce the necessary contact PRESSURE that is required to break the oxide layer and complete the circuit.  My 74 had green copper oxide all over the wiper switch contacts - it had to be disassembled and cleaned.

 

The steering wheel horn buttons have the same problem.  They get corroded and with low contact pressure, they actually don't conduct.  The OE horn button does not operating some "clicking" "over center" type switch - the button is connected to a chunk of brass (not copper) that you literally push onto another block of brass.

 

Without a cleanup, mine did not work.  Of course if you had some high current load, it would burn through the oxide layer.

[datzenmike]

Later vehicles switched to relays. They are so sensitive that a test lamp will trigger them. Thinner wires and contacts last forever and the relays are out by the battery for shorter wire runs.

[Stoffregen Motorsports]

Horns can get dirty inside and loose some of their volume. If you're confident in taking apart things that aren't meant to be taken apart, you can get inside and clean the contacts and then reassemble them.

 

Some horns use an adjustable contact and are easily adjusted and cleaned for proper pitch/volume.

 

Yes, adding a relay can increase the amps to the horns.

[paradime]

Back in the 80s a friend added a GM duel driver horn to his 510 and had to use a relay to keep it working. 

[Cardinal Grammeter]

9 hours ago, Stoffregen Motorsports said:

Horns can get dirty inside and loose some of their volume. If you're confident in taking apart things that aren't meant to be taken apart, you can get inside and clean the contacts and then reassemble them.

 

Some horns use an adjustable contact and are easily adjusted and cleaned for proper pitch/volume.

 

Yes, adding a relay can increase the amps to the horns.

 

I seem to recall the 620 has a relay.  I did adjust my horns for max output - is there a single "peak"?  (I'm not familiar with the mechanism.)  Disassembly and a clean might be in order - I can't imagine they were this soft when new.   (Also trying to figure out why the dash lights are so dim.  Lots of info how to upgrade but no explanation of what happened.)

[Stoffregen Motorsports]

The dash lights are also susceptible to resistance buildup in the wiring. Some guage panels lights have a resistors and such which multiply the issue.

 

When I'm in gauge cluster mode, I remove all the parts from the panel, including the printed circuit (if it has one) and clean everything with a chemical bath before reassembly. All the bulbs get replaced (just because) and all contacts are cleaned, with a scotch-brite pad if necessary. The light buld socket tabs get tested for fit, and if they are loose, I will slightly bend the contacts to make them fit a bit tighter.

 

If the cluster uses a rheostat, it can be cleaned too. The windings on old rheostats get gunked up which causes dim lights.