Horn - simple test ?

[Greg Bryan]

Jim - which diagram is closest to your car T1 or T2?
Regardless, grounding terminal 85 on the horn relay should make it click (and hopefully blow the horn).
If it doesn't click, use your ohm meter between terminals 85 and 86. I don't recall what the ohm reading should be, but it should be somewhere between 30 and 200 ohms, I imagine. That will confirm whether the coil is good. As John says above, it is basically an electromagnet that pulls the relay contacts together.
If it does click, you should measure battery voltage at terminal 87 at the relay during the click. If it clicks and you don't get voltage at 87, the contacts may be dirty, also as John says above. You can remove the metal can from the relay, it is held on with small tabs, and clean the contacts with very fine sandpaper.
I will bet an adult beverage that you are dealing with a combination of problems that are giving you the grief you're experiencing. Think of the system as two different circuits. The first is the coil - you need to have battery voltage at terminal 86 and the ground is completed through the brown wire, the contacts at the slip rings and then the horn button must provide a ground through the steering shaft. This is a low amperage circuit.
The other circuit is the high amp circuit that starts at the fuse block to the power in at terminal 30 on the relay. It goes through the relay contacts when the coil is energized and sends power to the horns. Since you've verified the horns work, the ground must be good at the horns.
You said you jumpered 30 to 87 on the relay and the horn didn't blow - doing that completely cuts out the relay - don't overlook basics: Is the car battery good, including the terminals and ground strap, the wire connection at the fuse box? - tighen the screw

[John Brooks]

One more thought. The horn is a pretty high current circuit. It possible to see 6v at the horn but the total resristance is too high to get enough current (Amps) to disengage the contacts in the horn. You have a meter. Set it on 10 amps, put the red lead in the amps plugs on the meter. Then ground one side of the horn (Brown wire) put the black lead on the other spade. Now put the red lead on the + side of the battery. The horn will blow, and the current in amps will read on th meter. Next put the red meter lead on the black and yellow wire from the horn relay and ground the wheel wire. If the horn does not work, switch the meter to volts, put the red lead back in the volt ohm plug on the meter and ground the wheel wire. Read the voltage. It should be a full 6v.

If you have the 6v, and no horn, the relay contacts need to be cleaned. They are just like the distributor points contacts. A little file and Emory cloth should fix it. Be sure to photo the wires before you remove the relay so it goes back in easy.

viewtopic.php?f=1&t=10599

[Jim Clement]

I wonder if this was the problem ?

[Jim Clement]

I ordered a new horn relay from Stoddard.. well labeled.. but not quite the same and had spade connections as opposed to the original ring connections from the wiring harness..
so I simply made 4 short connector pieces with a spade connector on one end and a small hook of exposed copper wire at the other.. bent the copper over the ring connector, small piece of electrical tape.. and back in business..
then installed the new relay into one of the original holes..
this is the first time the horn has worked in 30 years !! wow is it ever loud !!!

[Jim Clement]

okay.. here is the crazy thing..
I thought what do I have to loose.. so I took the cover off the relay and gave it a cleaning..
I think it might actually work..
it will only work in one side of the 87 terminal.. but they are jumper-ed together anyway.. or I could insert a small set screw into the second side..
I am very glad that I did not cut the ends off of the correct wiring in the car..
well.. I guess i know what I am doing tomorrow..
I used a light wire brush and some dental tools to get it unfrozen and cleaned up to this stage..

what would be the best / reasonable method of doing a better job of cleaning up the rust, without total disassembly ?

[Mike Wilson]

Try a Dremel with a small wire wheel/brush.

Mike

[Jim Clement]

thanks
The dremmel tool worked well.. although would have very much liked a mini bead blaster.
i got it cleaned up... and see why there are two connections to terminal 87.. so you can connect two horns.. except that the wires are actually jumper-ed together so you actually only need one.. and given that only one side of my relay will work, and that i only need one, I simply removed the terminal connection to the inoperative side.
so.. back in the car it goes..

[Mike Wilson]

Good fix, Jim!

Mike