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65 Riv Clam Shells start to open, but close straight away


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6 hours ago, Kevrev said:

My Clams start to open, but close straight away. I have disconnected the arms, but still does it, any ideas as to why

  Opening and closing cycles are initiated in the 4 prong relay. I would check or change the 4 prong relay, they are very inexpensive and available. Make sure the relay is properly grounded through its mounting screws.....clean, bright and tight!

Tom Mooney

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To diagnose this you need to unplug the electrical connector from the motor. One of the wires should

be 12 volts when the headlamps are turned off and the other wire should be 12 volts when the headlamps are turned on. If this checks out, you have a bad motor. If this doesn't check out, you have relay problems. 

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Below are some pictures of the headlight operating motor removed from the car. The first pictures shows the two micro switches on the right side. The second picture shows the operating lever on top of one of the switches (the small silver piece that is pointed on the end). The motor crank is the part with the two spherical studs on the ends. As the crank rotates, the bottom surface of it contacts the switch operating levers. That is how the motor operation is controlled.

 

 

 

 

 

499572846_HeadlightMotor3.jpg.thumb.JPG.bbd98eae98d1c943fe71de8790790492.JPG

Headlight Motor.jpg.JPG

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Two comments.......first, the limit switches are very very brittle and when adjusting them you can easily

shatter them. Second, they cut the power to the motor when a certain position is reached......I don't see how 

they could possibly cause the motor to reverse itself and open the clams back up because they are not designed to be able to do that. What normally happens when they aren't adjusted right

is that the motor continues to try to run with the clams closed resulting in a burned out motor and a dead battery, that is why Buick engineers retrofitted the auxiliary relay on the cars so that the battery would not go dead due to no power to the closing wire with the key off. Of course, the motor would try to run all the time when driving the car, so the motor would still burn out

very quickly when the limit switches quit working right. 

 

Edited by Seafoam65 (see edit history)
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OK, I've got this problem figured out....... I had to think on it for a while.....what you 've got is a bad

main relay. When you turn on the headlamps the main relay energizes and sends power to the wire that

opens the clams. What is  happening is that when you are turning on the lights and the clams start to open, and the circuit gets an electrical load on it,

the relay is internally breaking down and going back to it's default position, which is headlamps closed.  Tom Mooney's previous post is spot on.

Edited by Seafoam65 (see edit history)
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30 minutes ago, Seafoam65 said:

OK, I've got this problem figured out....... I had to think on it for a while.....what you 've got is a bad

main relay. When you turn on the headlamps the main relay energizes and sends power to the wire that

opens the clams. What is  happening is that when you are turning on the lights and the clams start to open, and the circuit gets an electrical load on it,

the relay is internally breaking down and going back to it's default position, which is headlamps closed.  Tom Mooney's previous post is spot on.

  It happens...Lol...even a broken clock is right twice a day!

Tom

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1 hour ago, Seafoam65 said:

OK, I've got this problem figured out....... I had to think on it for a while.....what you 've got is a bad

main relay. When you turn on the headlamps the main relay energizes and sends power to the wire that

opens the clams. What is  happening is that when you are turning on the lights and the clams start to open, and the circuit gets an electrical load on it,

the relay is internally breaking down and going back to it's default position, which is headlamps closed.  Tom Mooney's previous post is spot on.

That is certainly a possibility but I doubt that is what is happening. A relay has 2 separate  circuits within it. One is the control and the other is the controlled. The control circuit is the one that comes off the light switch. The controlled circuit is the one that activates the headlight motor which has its own set of contacts that are separate from the relay coil terminals. Because of this the relay coil does not see the load that it is controlling so the load has no affect on it.The coil moves the headlight motor activating contacts to open or close via magnetism. No mechanical or electrical connection between the two circuits.  You are correct that the default position is closed on the relay. But if the limit/ micro switch on the “ closing “ field of the motor is in the open  position when the headlights are turned on, ( which is what should happen),there will be no power  going to “ close “ field of the headlight motor so the motor would not go into the close mode. The headlight visor motor has 2 fields wound within it. One is the opening field the other is the closing field. The 2 micro/ limit switches at the top,in conjunction with the relay and headlight switch control when each of these fields get power. I could be wrong and it may be the relay but in my 30 years of working on much more complicated circuits involving relays , I’ve only seen them work or not work due to the relay coil or load contacts being burnt out. 

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If the relay fails internally for any reason, the way it is wired the motor will change direction. The fix will be either the main relay or a new/rebuilt clamshell motor.  I'm still betting it is the relay. It will be interesting to see how this turns out!

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2 hours ago, Seafoam65 said:

If the relay fails internally for any reason, the way it is wired the motor will change direction. The fix will be either the main relay or a new/rebuilt clamshell motor.  I'm still betting it is the relay. It will be interesting to see how this turns out!

True relay will go to default position which is closed but  motor will not be energized if micro/ limit switch for closed position is open.

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13 hours ago, Seafoam65 said:

OK, I've got this problem figured out....... I had to think on it for a while.....what you 've got is a bad

main relay. When you turn on the headlamps the main relay energizes and sends power to the wire that

opens the clams. What is  happening is that when you are turning on the lights and the clams start to open, and the circuit gets an electrical load on it,

the relay is internally breaking down and going back to it's default position, which is headlamps closed.  Tom Mooney's previous post is spot on.

Thank you THe relay is in behind the battery ?

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