Sudden battery drain with hot horn relay

[myles66]

So I just registered to the forum not too long ago and have been lurking for quite a while. I have a question that may have been answered, but I haven't been able to find it in FAQ.
I have a 66 gmc c1000 I bought about a month ago and am using as my daily driver. 3 weeks ago I replaced starter and battery cables, truck was running fine. Started on a dime up until this week a few days ago... I've been on vacation and haven't started the truck in two days, I get in and to my surprise... No power at all. Jumped batt for about 15 min and it started up, but horn relay was very hot to touch, let it idle for about 20 minutes. I shut it off and started right back up. Went out a couple hours later, dead as a door nail. Took battery to get tested, only had 3 volts!!! So it's charged at store and battery is good. Can my horn relay be causing this? I'd rather not take alternator off and starter off to get tested if anybody has had problems with a horn relay before. I'm no electrician by any stretch of the imagination, so maybe the horn relay couldn't drain the battery at all. Any advice or experience with this situation could be very helpful... And hopefully it doesn't cost a arm and leg to fix!!!
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[myles66]

Also I don't have a horn hooked up to horn relay, if that makes any difference? Is there a way to bypass or disconnect the horn relay completely?... Just more wires in the eng compartment than I need.
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[myles66]

Is there a way to completely take out horn relay from vehicle?
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[tincan1966]

These relays are common to stick and cause your problem.
If the relay is hot to touch and battery is losing charge, then most likely that is the problem. But to make sure it isn't a stuck horn switch, unplug the connector on the relay that has the black and green wires. If relay "releases" or cools down, then problem solved and you can leave it unplugged if you're not using it for the horn.
Just buy a replacement relay. They are not expensive.
GM used them as a junction for battery power to the ignition switch and the alternator.

If you want to eliminate the relay(not sure what you'd use for a horn, then) you can by simply splicing the large red wires together.

[myles66]

Hey thanks tincan66! I won't be using the horn at all, possible air horn with switch in the future. Just wanted to make sure I wouldn't overload anything bypassing the relay for the time being or unhooking anything, like I said im far from an electrician... Most of the time I'm just thinking of not getting shocked (got zapped by a faulty wired light socket 15 ft in the air, so yea. Me no Likey electricity. and now that you mention the horn being stuck I did pull it off and reinstall born parts to steering wheel, I'm sure I messed that up; luck is rarely on my side. Thanks again
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[myles66]

Tincan66 "If you want to eliminate the relay(not sure what you'd use for a horn, then) you can by simply splicing the large red wires together."

So what would I do with the black wire running from relay to pos on battery? Would it need to be spliced in to to the voltage regulator or something?
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[tincan1966]

Originally Posted by myles66

Tincan66 "If you want to eliminate the relay(not sure what you'd use for a horn, then) you can by simply splicing the large red wires together."

So what would I do with the black wire running from relay to pos on battery? Would it need to be spliced in to to the voltage regulator or something?
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Yes that wire will splice with the others. Normally this is a red wire from the battery. Basically what you need to do is connect all the wires together that are on the terminals with the screws. You can move them all to the same post and be done. That way no splicing wires. Just leave the green and small black wires disconnected.

[myles66]

Oh, I see... The po must've swapped that wire out. I'm finding a lot of things that have been "altered" as far as wiring both in the engine compartment and the cab, in other words I'm sure my days of headscratching and migraines have only just begun! Thanks again tincan66!
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