Clicking Sound When I Connect The Battery Terminal

[Gregski]

so I put together this '71 basket case GMC 1/2 ton 350/350 and when I connect the second battery terminal, don't matter which one plus or negative I hear a click in the cab, sounds like a relay maybe but I don't know which one or if it is normal

so can someone tell me if that is normal on these trucks, I don't think my '74 does that

[Stocker]

You might need to enlist a helper to make / break the battery connection while you track down the click. If I had to guess, I'd say it could be a relay.... possibly the horn relay under the dash, but that's just a wild guess.

[LockDoc]

Originally Posted by Stocker

You might need to enlist a helper to make / break the battery connection while you track down the click. If I had to guess, I'd say it could be a relay.... possibly the horn relay under the dash, but that's just a wild guess.

If it doesn't have air that would be my guess also. Unplug the horn relay and see what it does, it's just to the left of the steering column on the inside. Red, Green, and Black wires.

LockDoc

[Gregski]

Originally Posted by LockDoc

If it doesn't have air that would be my guess also. Unplug the horn relay and see what it does, it's just to the left of the steering column on the inside. Red, Green, and Black wires.

LockDoc

Thanks Doc, mine only has two wires going to that three prong plug Red and Green no Black wire? Does that mean anything?

[LockDoc]

Originally Posted by Gregski

Thanks Doc, mine only has two wires going to that three prong plug Red and Green no Black wire? Does that mean anything?

The black wire goes up the column to the horn contacts. Did you unplug the connector to see if you still had the click

LockDoc

[Stocker]

Any chance you're looking at a turn signal flasher?

[Gregski]

Originally Posted by Stocker

Any chance you're looking at a turn signal flasher?

both the turn signal flasher cylinder and the hazard cylinder have been unplugged and removed and the clicking still happens as soon as I touch the second battery lead to the battery post, it goes click, a single click in the cab

[Stocker]

Back to the horn relay then.... does the truck have working horns? Are the horns connected, or has the green wire been removed? Will the horns work if you touch a terminal with 12vdc?

[Gregski]

Originally Posted by Stocker

Back to the horn relay then.... does the truck have working horns? Are the horns connected, or has the green wire been removed? Will the horns work if you touch a terminal with 12vdc?

Spot on questions. I got the '71 truck with no engine wiring harness what's so ever. I got a '69 engine wiring harness for free when I bought the rear axle from the guy so I married that up to my truck. (As a side note, my truck is a '71 cab on a '69 six lug chassis.)

Then I found the big fat green horn wire cut on the '69 harness. So I went and bought a used green OE horn wire from a used truck parts place in town, so as of now I have the proper uncut green wire plugged into the bulkhead, but it is not connected to a horn at this time.

My truck came with no horn. So I bought a used OE horn from the same people as I bought the green wire, I have yet to mount it. Part of the problem was I could not tell where in the world the horn mounts to on the core support, I think I have seen now where it goes, I think there is a couple places but I will mount it just to the side of the radiator.

I am not sure if having the horn mounted with the green wire plugged into it will make the clicking go away but I am curious to try it.

Thank you for trying to help, and apologies for the long winded answer, but this is such a puzzle that I wanted you all to have all the pieces.

FYI: I am still missing that black wire that runs up the steering column and makes the actual horn button go Beep Beep.

[LockDoc]

Originally Posted by Gregski

both the turn signal flasher cylinder and the hazard cylinder have been unplugged and removed and the clicking still happens as soon as I touch the second battery lead to the battery post, it goes click, a single click in the cab

So you haven't unplugged the horn relay yet? If not that must be what is clicking then.

LockDoc

[Stocker]

Originally Posted by Gregski

I am not sure if having the horn mounted with the green wire plugged into it will make the clicking go away but I am curious to try it.

Connecting the green wire to the horn will not make the clicking go away.... it's just one more clue to the problem. With everything working properly, when the relay receives a ground from the horn button, it (the relay) sends 12V to the horns via the green wire.

If the click is the horn relay, having the horns wired would cause them to blow as soon as the relay operates. Best to track down the click without the horns hooked up!

Assuming the click is the horn relay, something is causing its input to be grounded. You don't yet have the black wire that is supposed to ground it.

First determine that the click is actually the horn relay, then track down the source of the stray ground.

[Gregski]

Originally Posted by LockDoc

Did you unplug the connector to see if you still had the clickLockDoc

I did, but I didn't report on it right away because I did it before and there was no click with it unplugged and so I plugged it back in and also no click, then a few days later it clicked again.

So I tried it again, unplugged the horn connector and no click plugged it back in no click, so we shall wait and see.

[Gregski]

the wiring mess was driving me crazy so I decided to clean it up a bit

now to be fair, I undid all the non sticky tape and freed all these wires, I don't know about you, but I can't read a wiring schematic worth a darn so I have to see and feel where my wires are going, I don't like it when a wire disappears into a mumbo jumbo huge wiring harness

I think I got it pretty clean, one thing I can't seem to understand, is what business do some wires have running from the wiper motor to the headlight switch, hmmm?

[Boog]

I find wiring confusing too. But you are in luck. There are a couple of wiring gurus on board here who can square you up in the wiring department.

[LockDoc]

Originally Posted by Gregski

the wiring mess was driving me crazy so I decided to clean it up a bit

now to be fair, I undid all the non sticky tape and freed all these wires, I don't know about you, but I can't read a wiring schematic worth a darn so I have to see and feel where my wires are going, I don't like it when a wire disappears into a mumbo jumbo huge wiring harness

I think I got it pretty clean, one thing I can't seem to understand, is what business do some wires have running from the wiper motor to the headlight switch, hmmm?

Sounds like the horn relay is bad then.

What color are the wires from the wiper harness to the headlight switch. I can't think of any that should do that. The Dk Blue, Lt Blue and Black wires go to the wiper switch and the Yellow goes to the fuse box.

LockDoc

[VetteVet]

Like they have said, if you unplug the horn relay and no more click, then it is getting grounded by the black wire. If you have no black wire then the relay won't click. It is supposed to run from the relay to the half-moon connector in your 4th and 5th pictures which is the turn signal connector. From there it runs up into the steering column to the horn button switch in the column.

There are no wires that run from the windshield wiper motor to the headlight
switch. You should have a yellow a black a light blue and a dark blue wires on the motor and the yellow wire goes to the fuse panel and the rest go to the wiper switch.

Here is a diagram of the underdash truck wiring. It shows the wiper motor connections in the upper left. There is a mistake in the yellow and black wire connection on the diagram. Yellow is hot and black is ground and it should go the washer motor connection.

If you follow the wiper motor wires in the first and second diagrams you can see that they yellow goes to the fuse panel and the rest go to the wiper switch in the second diagram.
Ignore the black arrows and the blue arrow. They are for another problem.
If you look at the left middle of the first diagram you can spot the red green and black wires going to the horn relay. Follow the black wire and it goes over and up to the half moon connector for the turn signal connector.

[Gregski]

Originally Posted by VetteVet

Like they have said, if you unplug the horn relay and no more click, then it is getting grounded by the black wire. If you have no black wire then the relay won't click. It is supposed to run from the relay to the half-moon connector in your 4th and 5th pictures which is the turn signal connector. From there it runs up into the steering column to the horn button switch in the column.

...

If you look at the left middle of the first diagram you can spot the red green and black wires going to the horn relay. Follow the black wire and it goes over and up to the half moon connector for the turn signal connector.

I truly can not thank you enough, for the great explanation and the diagrams, thank you so much for taking the time, it is very difficult to piece things together when you did not take them apart yourself and or when things are missing, your kind words really helped

however now when ever I plug the three wire connector into the horn relay the horn automatically sounds every time, so I have to leave the relay unplugged, is that a clue, is that a hint, do you think it's a bad relay, or is something grounding out in the steering column?

[randy500]

Originally Posted by Gregski

I truly can not thank you enough, for the great explanation and the diagrams, thank you so much for taking the time, it is very difficult to piece things together when you did not take them apart yourself and or when things are missing, your kind words really helped

however now when ever I plug the three wire connector into the horn relay the horn automatically sounds every time, so I have to leave the relay unplugged, is that a clue, is that a hint, do you think it's a bad relay, or is something grounding out in the steering column?

The horn blows when the black wire is grounded by the horn button. Does it have an aftermarket steering wheel? Usually that is the culprit, stock or aftermarket, remove the horn button and contact ring to find out why it’s grounded.

[Gregski]

I dislike abandoned threads so I just wanna close this one out with a small victory, well I think we found that short gentlemen.

the black wire being the horn wire!

[Gregski]

and the wheel back on and even the horn works now

I love this 67-68 wheel even though it's cracked, I don't care, my mother got it for me for a father's day present last year, and I just love the three spoke design, what a great center piece! brings a smile to my face every time I get in that bucket, know what I mean guys/gals?

['68OrangeSunshine]

The '67-'68 wheel is definitely a classic. Fits the hand just right.
Spokes at 9 O'clock and 3 O 'clock, so you can get the 'Ten and Two' we were tought in Drivers Ed, by feel. Also the spoke at 6 O'clock is handy when driving in reverse.
The slim shape also fits between the fingers when cruising.
I have a '71 Jimmy, and I put the OEM wheel back on it. [PO had a dumb Grant ghetto wheel that came off in my hands while in traffic]. While the original '71 wheel was a lot better, it hurt my hand trying to grip it between my knuckles like my '68's wheel.

I may change out to a '67-'68 wheel on that truck, too.

The original wheels are better made than the repops, I have heard.

About the cracks -- there are some old threads about fixing OEM steering wheels on here. Basically, you file out the cracks with a triangular file and fill back in with A/B putty, then sand down and paint.

[Stocker]

Originally Posted by Gregski

I dislike abandoned threads so I just wanna close this one out with a small victory, well I think we found that short gentlemen.

the black wire being the horn wire!

Yessir, you found the problem alright, good on ya! And thanks for the follow-up, all too often guys fail to do that and it leaves us not knowing what the problem was, or if it ever got fixed.