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1968 Generator and "pulsing" lights...

Started by Steve W, October 09, 2009, 03:49:38 AM

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Steve W

Its happened  twice now....I start the car at night, turn on the lights and the lights are somewhat "pulsing". Its not like they are turning on and off...just slightly dimming and then bright...at about half-second intervals.
Then, it usually stops after awhile.
I know my car has a generator....does that have anything to do with it? (All my previous cars had alternators)
No other symptoms...battery is fine, everything works, just the annoying "pulsing", or whatever you would call it.

Anyone?
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

The Tassie Devil(le)

Possibly a slightly worn Circuit Breaker inside the Headlight Switch.

These Circuit Breakers operate when there is a short in the headlight wiring, but in your case, the sudden drain on the system might be temporarily overloading a weakened bimetallic spring.

Or a bad Grounding at the Headlights, which gets a better contact after arcing a bit.

Bit hard to diagnose over the internet though.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

J. Gomez

Quote from: Steve W on October 09, 2009, 03:49:38 AM
Its happened  twice now....I start the car at night, turn on the lights and the lights are somewhat "pulsing". Its not like they are turning on and off...just slightly dimming and then bright...at about half-second intervals.
Then, it usually stops after awhile.
I know my car has a generator....does that have anything to do with it? (All my previous cars had alternators)
No other symptoms...battery is fine, everything works, just the annoying "pulsing", or whatever you would call it.

Anyone?

Steve,
Is the flickering also noticeable when you flip over to the high beams or just the low beams? Have you checked the connections at the foot switch beam selector?
If the flickering becomes more noticeable when you turn the high beams on (increasing the load) it could be a weak thermal circuit breaker at the switch as Bruce suggested, otherwise it could be in the foot switch selector.
J. Gomez
CLC #23082

"Cadillac Kid" Greg Surfas 15364

Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

bcroe

I'd try swapping in a spare alternator and/or check the alternator brushes.  68 alt uses an external voltage regulator.  Bruce Roe CLC # 14630

Misfit

The regulator is going bad. The points are opening and closing very fast. Open the hood with the engine running and the lights on. Use a stethescope or other item (long screwdriver) to 'listen' to the regulator. Hear is clicking real fast?
WARNING.....IF YOU HAVE LONG HAIR OR LOOSE JEWELRY, DON'T PERFORM THE ABOVE TASKS. YOUR HEAD WILL BE PULLED INTO SPINNING MACHINERY.
Now shut the car off, leaving the lights on. They stay the same steady brightness. If I were you, and that is the problem. I'd switch to an internally regulated alternator.

The swap is very minor, and the results are great.

MisFit

Steve W

Thanks for all the replies.  The reason I said the car has a generator is because the service manual says generator repeatedly, it never even mentions the word 'alternator'...so I just assumed. (I'm guessing they put an alternator in the car but kept on calling it a generator?)

And so far, so good. Here's an update:
I checked all the connections, all the wires coming off of the back of the alternator, gave em a quick shot of contact cleaner and made sure the connections were tight. Checked the connections at the voltage regulator too. Went to the battery and checked the cables,,,the ground was tight, but the positive cable seemed a bit loose. (I still have the original cables and spring clamps). Made sure it was tight and started the car and turned on the lights...then turned on EVERYTHING...not a single flicker!!!

So...I don't know if it was the battery cable (but that would be my guess) or the other connections...but everything is fine now.

Once again, thanks guys! This forum ROCKS!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

The Tassie Devil(le)

G'day Steve,

In the early days of the Alternators, the Auto Makers sometimes referred to them as Generators.

I think it might have been done to not confuse the motorists.

Actually, they do Generate Electricity.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Steve W

So...the battery died a few days ago. Went to start the car and it was just barely turning over, and then click, click click...
So, I have a battery charger, hooked it up, charged the battery and everything was fine...for awhile. Battery started winding down, so I went to the shop and the mechanic put his testers on the car and said..."the alternator is not putting out enough amps...about 12.7 or so. So the alternator isn't charging the battery. And MAYBE now the battery is going too, and while you're at it, lets put in a new voltage regulator. It'll only be about $360.00 for everything!"

No way.

I went to NAPA to get a remanufactured Delco-Remy alternator. It looked pretty much the same, but the mounting "ears" were different. It was the only alternator they had for my car, so I bought it.
(Now then, I have replaced alternators before on quite a few of my cars....normally a 15-30 min job. Pretty straight-forward, with or without the service manual.) Did not buy a battery or VR yet....want to see what happens by replacing the Alternator first.

But on THIS car...good god, what a major PAIN!  The A/C hoses are in the way, and they are not very flexible...PLUS...once the LONG bottom bolt is backed out it hits the fan shroud before it clears the alternator and bracket...so I had to stop and remove the fan shroud just to get that damned bolt out. (No mention of that in the Service Manual, BTW) THEN..these remanufactured Alternators have a bit of extra material on the bottom mounting "ear" making it impossible to fit the original spacer and complete the installation...so back to NAPA to have them grind about 1/8" off the spacer.

Then back to finish the install to find that the posts on the back of where the wires go are now positioned horizontally insted of vertically and the post labeled "BATT" almost hits the valve cover. I had to take the belt back off, install the wires on the post, then put the belt back on and tighten.  I found a rubber cap to put over the post so it won't "arc" to the valve cover.

Then the plastic plug that holds the two F1 and F2 wires in the middle started crumbling. After 41 years the plastic was just too brittle and it broke apart. So, back to NAPA for a new plug.

Finally finished the job, after surprising myself with a whole new vocabulary of curse words I didn't even knew I knew! Took hours to do what normally takes no longer than 30 mins on a "normal" car. (My 66 GTO, my 68 Camaro). Its cranking out the amps now too. About 14.5 on my little tester with a high idle.

Started the car, and when cold, with the choke on, the idle was high, and the pulsating lights started again.
After the car warmed up and the idle was normal. no pulsing! It only pulses at high revs.

Jeeze...I guess I'm losin' it....guess the next thing to do is replace the VR.
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

dadscad

I recently had a similar situation on my 63 CDV. The Alternator started loudly growling one morning going in to work, about 3 miles from the house. I turned around and took the car back home. When I shut it off in the garage the Gen lite did not go out. I disconnected the negative cable, locked up the garage and went to work in the truck. That day I picked up a rebuilt alternator from Advance auto that was close to the office.

That evening I installed the new alternator and cranked her up. Turned on all the lights, A/c on high. The lights were pulsating and occasionally getting very bright. The volt meter was running rampant between 14 & 14.9 volts. the tenths of a volt were running up and down slow enough I could read them but the hundredths were really flying up an down. The next day I picked up a new VR and installed it that evening. When I cranked it up the lights were steady and bright and the volt meter was siting steady at 14.58 vdc. The hundredths collum was fluctuating a digit or two every once and a while, other than that it was steady. I guess when the alternator failed it damaged the VR too.

David
Enjoy The Ride,
David Thomas CLC #14765
1963 Coupe deVille

man1ey

Quote from: Steve W on November 15, 2009, 05:06:01 AM
Jeeze...I guess I'm losin' it....guess the next thing to do is replace the VR.


For the money, replace that voltage regulator.  A solid-state regulator is a lot more reliable - I wouldn't buy an electromechanical regulator.  

The solid-state regulators are a lot shorter.  Electromechanical regulators are tall like the original.

I am an original-appearance guy and this is one of the few modifications I absolutely would recommend even if you really want to be original.  If you want it to look original, you could remove the plastic cover from your new solid-state v.r. and silicone the old cover on.  Nobody would ever know the difference.

Steve W

Thanks guys! Makes sense to replace the VR, and yes, I think I'll go with solid-state.
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Sweede64

I sugest yuo allways change the alternater and regulater as a unit, a bad alternater can kill a new vr and vice verca.
The name generator is correct in both cases, a alternater is a generator that produce AC, generators DC, in a alternator the AC must bee converted to DC before its used in the car.
The term shuold bee alternate current generator or direct current generator.
And your right, theese cars are a pa to work on....
Thomas Karlström

Steve W

OK..so I go to NAPA auto parts and ask them if they have a replacement VR for my car, and told them that I would prefer solid-state. They tell me. "sorry, but we only have ONE replacement VR for your car, and its the old style...and its 16.99".
So I say , OK...and figure I'll get that one for now.
After I get it home and open the box, there's a little note inside stating that all repacement VRs are now solid state! GOOD!

I installed it and now no more pulsing at all! It is also the same size as the old one, so I could swap the covers!
And what a treat, as well as peace-of-mind, to turn the key and hear that big motor fire right up.

Once again, thanks guys. Your advice was right-on!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

The Tassie Devil(le)

'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe