Wednesday, November 21, 2018

Which Direction?

Note the paper clip style tangs on the left of the cam and the contacts on the right base. You might wonder why there is a bit of black insulation on the top/left tang and it's because adjusting the tangs was a delicate process and I broke the tiny plastic 'spacer' that prevents the two tangs from touching. So I put the wire insulation over the tang to accomplish the same goal.

This should make everything clear as mud.

This pathetic silver 'push nut' is the cause of all this insanity. The two parts of the cam must be separate. The top turns on the stationary bottom base. So it can't be a tight nut that holds them in place. That push nut actually goes around the top of the turn signal arm attachment lever. As the push nut loosens the tangs no longer hit the contacts and I lose some portion of turn signals and brake lights

What I had to do is experiment with a  multi-meter and determine which tangs are hot at what times. The  tangs (when I flip the cam upside down) closest to the open 'C' are hot when the brake pedal is pushed. The Tangs furthers away from the 'C' opening are hot when the key is in the aux/run position. Ok? Then the base contacts are situated as it is installed...the right side top is the Right Tail Light contact. The Right lower is the Left Tail Light contact. The left lower contact illuminates the right dashboard indicator lamp. The top left contact illuminates the left dash indicator light. See?

So, when everything is normal and I'm not making a turn but I HIT THE BRAKE, what happens is 12v goes to the inner tang and sends 12 to both contacts on the right (right and left brake lamp). And when I'm driving and the key is in RUN then the outer tangs are also hot with 12v and when I turn left, for example, that 12v is sent to the top left contact (left dash indicator) and the lower right contact (Left tail light).,..since it also passes through a relay for the turn signals it will blink...and also cut out my brake lights. Yes, in 1969 I only had the option of indicating a turn or indicating I am stopping....I can't indicate both at once. The turn signal cuts out the brake light and blinks it instead...although the opposite brake light will come on.

I spent two days figuring out this info and although it all works right now the push nut is still going to wear out and get loose and then the contacts will not touch and I will be back to the same problem. But at least I know what the problem is and that's a positive step. Obviously, the whole assembly needs to be replaced and I promise that will happen soon. This cam is worn out, as can be seen from the amount of copper worn off the contacts. The one detail I didn't get a photo of is the custom plastic shims that I put on the handle shaft before I put the cam over it. The shim forces the cam higher so the push nut will be tighter once I hammer it on. I'm proud of that plastic shim because it had to be cut from plastic packaging with a hole the size of the turn handle shaft.
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Man in the Van by Oggy Bleacher is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.