Electrical Problem

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Electrical Problem

Postby Maine Pilot » Fri Sep 29, 2017 9:55 am

This might be considered a "general" problem and not limited to my '66.

Lately, when driving at night I've noticed the headlights/radio/dashboard lights all brightening up momentarily then dimming whenever the horn is used. Last night I had to make a "panic stop." I hit the horn at the same time with the previously mentioned results except this time the horn's volume was much lower and it sounded at a much lower frequency. So I'm thinking, there's got to be a voltage drop--possibly due to the battery?

The battery came with the purchase of the car 5 years ago, but I don't know when the previous owner installed it. During winter storages I've attached a float-type battery charger and throughout the driving year there seems to be plenty of cranking power for start up.

Is this an indication the battery is starting to go or should I be looking elsewhere such as the alternator?
My wife says I only have 2 faults. I don't listen...and something else
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Re: Electrical Problem

Postby Comechero65 » Fri Sep 29, 2017 11:52 am

Maine Pilot wrote:This might be considered a "general" problem and not limited to my '66.
Lately, when driving at night I've noticed the headlights/radio/dashboard lights all brightening up momentarily then dimming whenever the horn is used. Last night I had to make a "panic stop." I hit the horn at the same time with the previously mentioned results except this time the horn's volume was much lower and it sounded at a much lower frequency. So I'm thinking, there's got to be a voltage drop--possibly due to the battery?
The battery came with the purchase of the car 5 years ago, but I don't know when the previous owner installed it. During winter storages I've attached a float-type battery charger and throughout the driving year there seems to be plenty of cranking power for start up.
Is this an indication the battery is starting to go or should I be looking elsewhere such as the alternator?

It's very likely the batt being 5 years old at least could be at the end of it's life. Most batteries don't last any longer than that and many don't even make it that long. Only the best i have found last a max of 7 years.
But there still could be other things like poor connections including grounds, loose fan belt or brushes going bad in gen or alt.
The horns can sound weak or not working well can happen even when everything is good as ford did away with the horn relay in 65 so that alone makes for lousy horns. Best thing i ever did was adding my own horn relay. Add your own relay.
Swap in another known good batt as a test and as the quickest fix. If the problem is still there then dig deeper.
Ron
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Re: Electrical Problem

Postby popscomet » Fri Sep 29, 2017 2:40 pm

IT seems to me that a battery on a gen lasts longer then one on an alt,,,this old comet has had the same batt for yrs,,,It doesn't have big stero and speakers and AC and all other power draining stuff, but it does have MSD ign,,but even on all my tractors with a gen ,,seems like the batt's last longer...I buy good batt's to start with and the tractors are not driven in the dark having to have lights,,,as really my comet anymore is seldom driven at night other then once a month when I take it to a monthly cruise,,,,all my short lived batt's are always on a alt...it may not be nuttin to it,,but for me it sure seems that way... :shock: :shock: pop
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Re: Electrical Problem

Postby lavron » Fri Sep 29, 2017 2:53 pm

popscomet wrote:,It doesn't have big stero and speakers and AC and all other power draining stuff, but it does have MSD ign,,but even on all my tractors with a gen ,,seems like the batt's last longer


I don't know if it is generator or drain, my old tractor has an alt. and I finally changed the battery last year after 8 to 10 years (I can't really remember it has been so long) and that is even with the tractor sitting for extended periods without being run plus the battery is not even protected from the elements too well.

I did finally change the battery on the truck last year and it looked like the original 2006 battery, I hope the new one lasts that long. The indication I had with it was it cranking slow never noticed lights dimming etc. or course we are talking 60's tech vs 2K tech a lot has changed.

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Re: Electrical Problem

Postby Lou's Comet » Fri Sep 29, 2017 4:40 pm

Maine Pilot wrote:This might be considered a "general" problem and not limited to my '66.

Lately, when driving at night I've noticed the headlights/radio/dashboard lights all brightening up momentarily then dimming whenever the horn is used. Last night I had to make a "panic stop." I hit the horn at the same time with the previously mentioned results except this time the horn's volume was much lower and it sounded at a much lower frequency. So I'm thinking, there's got to be a voltage drop--possibly due to the battery?

The battery came with the purchase of the car 5 years ago, but I don't know when the previous owner installed it. During winter storages I've attached a float-type battery charger and throughout the driving year there seems to be plenty of cranking power for start up.

Is this an indication the battery is starting to go or should I be looking elsewhere such as the alternator?


If it cranks good and the problem only occurs when you use the horn then,
I would check the horn first, might be going bad. Bat is 5 years old how old is the horn?
Also check the ground on the horn . After checking the horn and it's ground I would move on to other items.

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Re: Electrical Problem

Postby Maine Pilot » Sat Sep 30, 2017 5:57 pm

Thanks for all of the responses to my question. I intend to use your suggestions next weekend when I'll have some free time.

Does anyone have a theory why there's a brief brightening of the lights before they dim-- It almost sounds like a momentary voltage surge?
My wife says I only have 2 faults. I don't listen...and something else
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Re: Electrical Problem

Postby Comechero65 » Sat Sep 30, 2017 6:45 pm

Maine Pilot wrote:Thanks for all of the responses to my question. I intend to use your suggestions next weekend when I'll have some free time.

Does anyone have a theory why there's a brief brightening of the lights before they dim-- It almost sounds like a momentary voltage surge?

If you know for a fact that the batt is good then the dimming is either a failure in the charging circuit either the alt or regulator. The horn issue is another problem and probably not related. From 65 on horns didn't work well after the horn relay was elininated. Adding your own horn relay may resolve that problem. Been there.
I would dwell on the charging system first.
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Re: Electrical Problem

Postby Jims65cyclone » Sat Sep 30, 2017 8:55 pm

I had a Nissan pickup truck that the battery pooped out on my way home from work one day. All of a sudden the radio got louder. Didn't know what was going on until the next time I tried to crank it and it wouldn't even grunt. My theory was that the battery must have open-circuited, and I was putting the full 14+ volt output of the alt. through the system without the resistance of the battery. That's a weak theory that may, or may not hold water, or acid, as the case may be. :roll:
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Re: Electrical Problem

Postby Comechero65 » Sun Oct 01, 2017 12:39 am

Jims65cyclone wrote:I had a Nissan pickup truck that the battery pooped out on my way home from work one day. All of a sudden the radio got louder. Didn't know what was going on until the next time I tried to crank it and it wouldn't even grunt. My theory was that the battery must have open-circuited, and I was putting the full 14+ volt output of the alt. through the system without the resistance of the battery. That's a weak theory that may, or may not hold water, or acid, as the case may be. :roll:
Jim

Never heard that theory before and never even thought it could happen but who knows. Anythings possible. I would think once the charging circuit loses the load of the battery the regulator should still hold the output at the regulated setting. But electrical devices can sometimes do weird things and it may be possible that either it could act like an intermittant connection or the reg goes irregular and sort of flutters. The headlights flickering could be a result. Don't know how else to explain it. Who knows maybe the Nissan reg was poor quality or badly designed. Or that any reg could handle a load that comes and goes intermittanly.
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Re: Electrical Problem

Postby Lou's Comet » Sun Oct 01, 2017 9:14 am

Maine Pilot wrote:Thanks for all of the responses to my question. I intend to use your suggestions next weekend when I'll have some free time.

Does anyone have a theory why there's a brief brightening of the lights before they dim-- It almost sounds like a momentary voltage surge?


This only happens when you use the horn??

Do you get the same effect(brief brightening and then dimming lights) when you use any other electrical items? Such as wipers, heater blower motor, brake lights, etc. when driving at night?

The brief brightening before they dim could be like a momentary voltage surge. When you hit the horn the VR senses the voltage drop and has the alt put out more for the demand. The initial increase in voltage from alt could be the brief brightening.

If it is only happening with the horn then that is where I would start. Even if it was to eliminate the horn as the problem.

Assuming you have two horns a high and low. Quick and easy test would be to disconnect one horn at a time and see if the problem goes away. I would disconnect the high horn first(reason being you said last time your horn worked at lower freq)

Not sure if the horns are marked high and low but disconnect one see if problem still there then reconnect the one and disconnect the other and see if problem still exists

Next I would check the amperage draw of the horns. test the draw of each horn and test the amperage draw at the power supply wire for the horn going into the steering column just in case something flakey is going on inside the column.

Does the car have any amp or volt gauge? Or a light? If it has a light does it come on.

Just some ideas.

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Re: Electrical Problem

Postby Maine Pilot » Mon Oct 02, 2017 8:10 am

Lou:

I've only notice this condition at night, but yes, whenever another electrical accessory is used, there's a slight dimming, (compared to using the horn.) There's the standard dashboard AMP gauge, but it's essentially useless--no deflection of the needle even with the engine off and using the lights, horn, cigarette lighter, etc.

I'm on a short vacation for the rest of this week, but when I return, I'll go to the local Auto Zone store as they advertise they'll check your battery for free. My cheap, (free from Harbor Freight) multimeter), shows the battery at 12v.

Bob
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Re: Electrical Problem

Postby Lou's Comet » Fri Oct 06, 2017 7:02 am

Maine Pilot wrote:Lou:

I've only notice this condition at night, but yes, whenever another electrical accessory is used, there's a slight dimming, (compared to using the horn.) There's the standard dashboard AMP gauge, but it's essentially useless--no deflection of the needle even with the engine off and using the lights, horn, cigarette lighter, etc.

I'm on a short vacation for the rest of this week, but when I return, I'll go to the local Auto Zone store as they advertise they'll check your battery for free. My cheap, (free from Harbor Freight) multimeter), shows the battery at 12v.

Bob


Bob,

Hope your mini vacation is going good!

Your Battery seems a little low, volt should be 12.4 or better. Autozone will want to sell you a new one.

Even with your batt being low i don't see how it would cause your problem (lights brightening momentarily then dimming with horn use)

You said the car cranks good and starts up. Once the car is running the alt/VR take over. Now if the alt or voltage reg were going bad I could see it causing your problem. But if the alt or VR were causing your problem you would have the same problem/effect when you use any item of higher electrical demand such as heater blower motor, wipers on high, etc.

You do say you have a slight dimming with other items that draw a higher demand. But from what I get from your post it is much worse with the horns? IMO this shows something with the horns is drawing excessive current

As I said earlier first I would try disconnecting the horns one at a time to see if any improvement. The even disconnect both and try it. If problem still exists with both horns disconnected then you have a problem with the horn wiring or in the column.

Also test your volts at the batt with the car running and see what you have.

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Re: Electrical Problem

Postby poboyjo65 » Fri Oct 06, 2017 10:19 am

when I put my car back together I bought a new voltage regulator for it. the head lights would dim & do crazy things after a good 2 or 3 gear floggin, & sometimes for no reason. I bought another new reg. still did it. I finally put the old rusty old style one back on & it cured it. for some reason the newer type regulators dont do right in my car, & have heard of others doing this too. do you have the newer thinner style or the old thick v. regulator?
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