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Discussion Starter #1
I have a parasitic drain on my battery. In trying to track it down, I must have done something because my horn stopped working and my ammeter is in the discharge side, always. I pulled the wire that powers the radio memory, but when I went to plug it back in, (as I was driving) I missed the proper aux spade in the fuse block and I saw sparks. After that no horn. There are some other wires that are spliced in and also connect with the radio memory. I am not sure what they are for. I checked and the fuses and the fuseable links all look intact. I think it may be the horn relay. Is there a test to check that relay? Maybe I missed something even more obvious. I have been disconnecting the battery at night and putting the charger on the battery. Maybe I damaged the voltage reg., too when I shorted out the memory connector? I am just lost what to do nest.
 

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A troubleshooting tool is a test light - say a 1156 in a socket and place the test light between a battery cable and battery post as the light filament will limit current demand.
If the light glows brightly - short somewhere - pull fuses helping isolate the circuit at fault.
The light should glow very dimly as the radio memory and clock using minuscule power.

Horn relay is simple - battery power -pink wire and black wire - horn button - jumper a ground wire to the black wire
and relay should click and horns work if buss bar has power from battery - big red wire(s).
Might try horns by themselves first.
Here's some diagrams to help. Take pictures, write notes, to your set-up for future reference and to regain electrical system integrity.
Ammeter always stuck in discharge when not running, battery disconnected, or only engine running?
 

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Follow Everett's advice ... I bought a light stick at Auto Value and used it alot when trouble shooting under the hood.

 

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You might look at the fusible link at the Horn Relay - which being the Swiss Army Knife of the electrical system has a few duties.

Do you hear a click when you press the horn button? If so at least the relay side of the the device is still working.

As for the drain, using Everett's troubleshooting advice will narrow it down in short order. However you may have complicated the situation if your distracted driving event shorted out anything in the fuse panel/bulkhead connector.
 

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Discussion Starter #6
I did a check on the horns, both high and low work when powered directly. Just rechecked the ammeter and it is working just as it did after I rewired it last year. Although, it reads in the discharge side at idle and goes up to just short of 12 O'clock (still discharge) when revs are increased. I am thinking I may have damaged the horn relay when I was trying to connect the radio. Checked all the fuses in the block, they were good. Is there a bench test for the horn relay if I take it off?
 

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I forgot one schematic - like it shows - hot power is there already just ground the other coil terminal and the horns will sound or relay will click.
Relay no clicky, and no horns, corroded relay contacts
Relay clicky and no horns, bad relay contacts for horn circuit replace relay or wire brush terminals on buss bar and bar itself and reassemble.
Relay clicky and horns with jumper - bad steering wheel circuit.
 

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Yes you can bench test the relay with a 12 volt supply or spare battery. I'm assuming we are speaking about the 67 RS here so no "key minder" function, only a pair of terminals besides the power "Bus bar" connection. The part number should be 1115837. Black plastic base, metal cover. However someone could have installed a 68-69 unit that has the "key minder." Looks identical but has the extra terminals for the door jam alarm.

To bench test a 67 ground the body of the relay to your negative pole of your bench power source with a test lead, then connect positive to the bus bar.

Hook a test light to the green terminal - this is the out to the horns and ground the other leg of the test light.

To test the relay: Ground the black terminal. If the relay is working you will hear it click and the light will go on. No click the points are fused or the coil is broken.

These units can be rebuilt by hand in less than an hour using a fingernail emery board from the dollar store, and if the coil wire is broken needle nosed pliers.

Use the board to clean and resurface the points contacts on the relay. If the coil wire is damaged you can repair the winding as well, by making a small twist connection between the two broken segments. just two or three turns should do it.

Or for a couple bucks at RockAuto buy a replacement relay and call it done.
 

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Ammeter check - use voltmeter and check alt BATT stud referenced to ground and note reading - should not be less than 13.5 volts at idle if OE design system - 10DN alt w/external reg.
Not measure across battery posts and should be less than 0.4 volts difference from above.
if more difference, then wire brush battery junction terminal AND check fusible link of positive battery cable and replace cable if needed.
And if you buy a horn relay, buy an electronic regulator and swap out. Be the best $20 you ever spent and don't forget the reg ground wire.
Might as well pick up an alt belt also.
 

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Discussion Starter #11
Thank you, good advise. When I took the cover off the relay, the coil looked very old and covered with a rust like substance. The wires were connected but a little loose around the coil. I gave the coil a shot of WD-40. Put it back in, no click when horn button closed. However, when I manually closed the contact, the horns work. I'll try the file on the points. If that doesn't work, I may look for the electronic relay. I think radio shack has them. Just need to find that article on wiring an electronic relay. I must say how much I appreciate the tutorial on rebuilding the relay. I really prefer to stick with all the OEM, if I can.
 

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I'd get a voltmeter and measure battery voltage when the car has not run for a few hours and when running. The ammeter doesn't tell you much, particularly because it isn't. Its a sensitive voltmeter fed from 2 slightly different 12V sources.
Not sure what WD40 is supposed to do. I don't have any or I'd check to see if its conductive. Toss it in the trash.
I wouldn't be too aggressive filing relay points.
Chances are the charging system is fine, but the gauge is wrong. The battery voltage measurements will tell the story. A test light won't tell you a thing related to charging.
 

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Discussion Starter #13
Thank you, I used the voltmeter as you suggested. I found that my radio puts a parasidic drain on the battery. I have a MSD box, too and suspect it too is energized somewhat even with the ignition off. I put a 98 amp alternator on last year, but it never puts out more than 13.5 volts; just over 12.0 at idle. I probably should have converted to an internal regulator when upgrading my alternator. Would the voltage regulator be the reason that the alternator output is so anemic? At, any rate, I now, know that the ammeter is (as you said) it not very accurate. I tracked down the horn issue to the horn button contact. It's fixed.
 
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