1964 Malibu horn relay - Page 3 - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

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post #31 of 47 (permalink) Old Apr 9th, 17, 6:40 PM Thread Starter
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Re: 1964 Malibu horn relay

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Originally Posted by Dean View Post
In the places where GM had fusible links originally, yes, don't replace fusible links with fuses.
Thanks. Would you stick with original wire size? I mentioned above I was thinking 8 gauge with a 12 gauge fuse wire. I have a 63 amp internal alternator.
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post #32 of 47 (permalink) Old Apr 9th, 17, 8:35 PM
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Re: 1964 Malibu horn relay

Let's back up a bit, shall we?

First off, there were no fusible links in Chevelles in 1964. It wasn't until the 1967 model year. Can you add them to mimic the later years to provide additional protection? Yes. The one catch being, if the 14 ga. fusible link from battery (+) then spliced to the 10 ga. charging line is added, I'm not sure if this will change the ammeter accuracy (well as accurate as it was meant to be in 1964).

I think there's some confusion. The 14 ga. fusible link that is the main battery connection feed to everything in the car other then the main stud on the starter beginning in 1967 is designed to protect the alternator charging circuit as well as the real estate from battery all the way to the horn relay distribution connections. This is not just to protect the horns. You don't want to use fuses or breakers in these main feeds, that is why the BIG 3 went with fusible links, --unsurpassed reliability. Later years used roughly 16.5" of 14 ga. fusible link wire from the battery (+) terminal to the main 10 ga. charging line that runs across the radiator support to the horn relay.

If the car is staying with a factory system for the most part, then you don't want to upgrade the feed that runs across the radiator support from battery (+) to horn relay. the 10 ga. wire is sufficient and the length and gauge provides some current limiting for proper battery charging.

1964 is not my year of specialty, and this is a unique issue with changing the alternator location as the wiring changes from the original design/operation of the ammeter shunt.

You're going to have to isolate your red wires at the horn relay and shunt resistor connections to verify what is what for proper connection.

Assuming the schematic provided earlier in this thread is half-way accurate......

The red that is the main feed for the vehicle interior (that comes out of the bulk head connector) will have to connect to the horn relay bussbar (the two screws on the side are your bussbar). The wire you run across the radiator from the battery (+) will have to go to one side of the ammeter shunt. The other side of the ammeter shunt will connect to the horn relay bussbar.

The alternator charging wire that starts it's journey at the rear lug on the alternator will connect to the horn relay bussbar.

This isn't exactly cut-n-dry due to the changes made in the vehicle.

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post #33 of 47 (permalink) Old Apr 9th, 17, 9:19 PM Thread Starter
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Re: 1964 Malibu horn relay

Joe, thanks for the info, I didn't realize I didn't need the fusible link. Is there anything in the system that protects from a surge then?

The manual says the wire running through the rad support from the battery to ammeter / horn relay is 12 gauge, but like you said, it's not cut and dry because it isn't all original.
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post #34 of 47 (permalink) Old Apr 10th, 17, 5:26 AM
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Re: 1964 Malibu horn relay

As I said, you will be fine with the fuse. And about carrying spare horn fuses in case the fuse blows........
There are 2 reasons why the fuse might blow:
[1] It is underrated for the device it is protecting.
[2] There is a current overload or short somewhere.

Continual blowing of the fuse of the correct rating is telling you that the fuse is [a] doing it's job & [b] you need to investigate what is causing it to blow.


There is no more reason to carry spare horn fuses with you, than there are reasons to carry other fuses used in the car.
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post #35 of 47 (permalink) Old Apr 10th, 17, 5:28 AM
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Re: 1964 Malibu horn relay

ps,
the pic of the fuseholder you showed is ok, but I would get an inline fuseholder that takes the modern blade type fuses. They are more robust.
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post #36 of 47 (permalink) Old Apr 10th, 17, 9:54 AM
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Re: 1964 Malibu horn relay

Quote:
Originally Posted by Coppertop View Post
Let's back up a bit, shall we?

First off, there were no fusible links in Chevelles in 1964. It wasn't until the 1967 model year. Can you add them to mimic the later years to provide additional protection? Yes. The one catch being, if the 14 ga. fusible link from battery (+) then spliced to the 10 ga. charging line is added, I'm not sure if this will change the ammeter accuracy (well as accurate as it was meant to be in 1964).

I think there's some confusion. The 14 ga. fusible link that is the main battery connection feed to everything in the car other then the main stud on the starter beginning in 1967 is designed to protect the alternator charging circuit as well as the real estate from battery all the way to the horn relay distribution connections. This is not just to protect the horns. You don't want to use fuses or breakers in these main feeds, that is why the BIG 3 went with fusible links, --unsurpassed reliability. Later years used roughly 16.5" of 14 ga. fusible link wire from the battery (+) terminal to the main 10 ga. charging line that runs across the radiator support to the horn relay.

If the car is staying with a factory system for the most part, then you don't want to upgrade the feed that runs across the radiator support from battery (+) to horn relay. the 10 ga. wire is sufficient and the length and gauge provides some current limiting for proper battery charging.

1964 is not my year of specialty, and this is a unique issue with changing the alternator location as the wiring changes from the original design/operation of the ammeter shunt.

You're going to have to isolate your red wires at the horn relay and shunt resistor connections to verify what is what for proper connection.

Assuming the schematic provided earlier in this thread is half-way accurate......

The red that is the main feed for the vehicle interior (that comes out of the bulk head connector) will have to connect to the horn relay bussbar (the two screws on the side are your bussbar). The wire you run across the radiator from the battery (+) will have to go to one side of the ammeter shunt. The other side of the ammeter shunt will connect to the horn relay bussbar.

The alternator charging wire that starts it's journey at the rear lug on the alternator will connect to the horn relay bussbar.

This isn't exactly cut-n-dry due to the changes made in the vehicle.
Well there I go jumping in and posting without reading again.
Can't seem to get out of that habit although I didn't know there were no fusible links in 64 and what I said about never replacing a GM fusible link with a fuse is true, it just doesn't apply to 64's if there were none.

Maybe the time has come for me to quit trying to help.
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post #37 of 47 (permalink) Old Apr 10th, 17, 5:31 PM Thread Starter
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Re: 1964 Malibu horn relay

Quote:
Originally Posted by Dean View Post
Well there I go jumping in and posting without reading again.
Can't seem to get out of that habit although I didn't know there were no fusible links in 64 and what I said about never replacing a GM fusible link with a fuse is true, it just doesn't apply to 64's if there were none.

Maybe the time has come for me to quit trying to help.
Don't you dare! Since I bought my Malibu and joined this forum I have read through a lot of threads here and your advice has been awesome.
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post #38 of 47 (permalink) Old Apr 10th, 17, 6:41 PM Thread Starter
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Re: 1964 Malibu horn relay

So I called M&H who I bought the wiring harness from and they suggested a 10 gauge charging wire (from battery to horn relay via the rad support). The original system calls for a 12 gauge wire. They said there would be no harm in going with an 8 gauge wire. Agree/disagree?
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post #39 of 47 (permalink) Old Apr 11th, 17, 5:14 AM
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Re: 1964 Malibu horn relay

There is no harm done going to a thicker cable than is needed to get the job done...except to the wallet & you are adding unnecessary weight.
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post #40 of 47 (permalink) Old Apr 11th, 17, 11:09 AM
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What is being missed here is the wire gauges chosen were to provide inherent current limiting. 10 ga. For a max alternator output of about 63 amps. Read the MAD website, he spells this out.
The charge line should be no bigger then 10 ga. to maintain the factory design--which has worked fine for not destroying batteries over the last 50+ years.
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post #41 of 47 (permalink) Old Apr 11th, 17, 11:11 AM
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Re: 1964 Malibu horn relay

Also, fuse links will always trump replaceable fuse and fuse holders when properly installed as far as longevity and reliability goes (if you choose to install them).
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post #42 of 47 (permalink) Old Apr 11th, 17, 12:07 PM
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Re: 1964 Malibu horn relay

I don't want to get too far off track here but, because we are on the subject. Why are fuse links better? Because of the "slow blow" characteristics or something else? Would a self resetting breaker of the correct voltage and amperage be even better yet?

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post #43 of 47 (permalink) Old Apr 11th, 17, 8:31 PM
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Re: 1964 Malibu horn relay

Darren,

Better for certain applications...

Let's back up. We are saying (if chosen) to protect the main charging line to the battery. We're not fusing the horns alone.

Fuses and fuse holders are NOT the choice for "mission critical" stuff like this. The wire from the battery to the horn relay is responsible for providing power in order to activate the starter solenoid, provide all the power until the alternator can or be responsible for ALL the loads if the charging system quits as well as providing the link between the battery and alternator so there is filtering of the DC in the system.

The best fuses and holders and breakers are still an introduced weak point-- for oxidation, temperature cycling, etc. When I worked for the State Patrol as a Senior Electronics Tech, you soon see with a fleet of hundreds of vehicles how even the best fuse holders, fuses, breakers, etc. succumb to not only the elements, but just age. And we're not talking vehicles used for 40 years. Some were not even subject to extreme duty fatigue.

Fusible links? Not so much. Why? It's a wire, spliced to another wire and then sealed where the splice is. It is not going to oxidize unless it is physically damaged. It's not going to get "weak" with age like a circuit breaker or certain fuse holders. They provide protection against catastrophic overload (without nuisance blowing or tripping when unexpected higher then normal increases in current draws take place) while maintaining this high level of long term reliability.
That is why they were used over a half century ago and still used today.

Fuses and breakers have their place, but I wouldn't want one in this location.
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post #44 of 47 (permalink) Old Apr 12th, 17, 4:43 AM
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Re: 1964 Malibu horn relay

He asked about the wire gauge for the horn relay wire, which is what I responded too.
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post #45 of 47 (permalink) Old Apr 12th, 17, 5:08 AM
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Re: 1964 Malibu horn relay

I do not agree that fusible links [ FL ] 'trump' replaceable fuses. It depends...
Many FLs are hard wired into the harness, making replacement difficult. Also, there tends to be just one FL in the alt cct, which is 'on' all the time the engine is running & has the highest current flow of the car's electrical system [ other than the starter & it's solenoid, only momentary use during starting ].
So it makes sense to use the FL in this situation, with it's high current rating.

Today's blade type fuses are an encapsulated fuse & are very reliable. No reason not to use to protect sub-circuits.

In the case of this thread, & the OP connecting his horn: if power to the horn relay is spliced into the alt main wire, you would NOT want to use the alt's FL to protect the horn cct, because the horn relay wire [ thin ] would have to draw a HUGE amount of current to open the FL. The horn wire could burn before the FL opened.
My assumption, & comments, are in the belief that the OP intends to power the horn relay direct from the bat [+] terminal or the alt terminal. Either way, the most effective protection is an inline fuse [ or cct breaker ] in the feed wire to the horn relay.
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