Steering Column Horn/Flasher Connections

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Carl Luck
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Steering Column Horn/Flasher Connections

#1 Post by Carl Luck » Fri Jun 16, 2017 10:03 am

I'm all most there with reassembly of the electrical circuits on my 59' 356A coupe but have a problem with the horn connection. I have a solid 2 ohm resistance between the copper sleeve and the steering column. The flasher, lower band, is OK. I have taken it apart several times, cleaned everything, put a sleeve down the wire length inside the column, flossed the gap in the insulator under the copper band and nothing effects the 2 ohm reading. There is no resistance in between the copper strap and the wire terminal at the steering wheel end. I am not sure it worked when I bought the car ~20 years ago, or ever worked???
Any suggestions/ideas would be greatly appreciated. Fall back is to forget the flasher and use the lower band for the horn!
Carl

Robert Vaughan
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Re: Steering Column Horn/Flasher Connections

#2 Post by Robert Vaughan » Fri Jun 16, 2017 5:23 pm

Can a photo help explain the objects that are making trouble? I don't understand where the resistance measurement is being made (from / to).

Carl Luck
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Re: Steering Column Horn/Flasher Connections

#3 Post by Carl Luck » Fri Jun 16, 2017 5:45 pm

Unfortunately I didn't take any photos before reassembling and temporarily moving on. There are two copper bands around the inner steering columns that the horn and headlight flasher connect to. There is then a wire for each that is brought up the center of the column and connects to the horn button and horn ring on the steering wheel. With everything disconnected, I am measuring the resistance from the copper ring to the column itself. This should be an open circuit, I believe. It is for the flasher but the horn ring is shorted to the column, almost, 2 ohms. Flasher ring to column is open, greater than 1,000 ohms, makes sense. Close inspection shows no issues.
Worst case, no flasher and the horn gets connected to the copper ring that is not shorted but I sure would like to have everything correct and working.Thanks for helping find the issue.
carl
 

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David Jones
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Re: Steering Column Horn/Flasher Connections

#4 Post by David Jones » Fri Jun 16, 2017 7:20 pm

Carl, first off are you connecting the horn and flasher to the right place. On the "A" car the button in the center is the headlight flasher and the ring is the horn operator. The two circuits are the same in that they use a carbon brush to contact the copper strip so there will be some resistance there. I cannot remember what the circuit contacts look like under the headlight flasher button but I suspect that the problem will lie there. Connect everything up and see if it works then start digging further if neither horn or flasher relays work.
I assume you have a workshop manual so you are not flying blind.
If I had known I would live this long I would have pushed the envelope a little harder.
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Jim Alton
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Re: Steering Column Horn/Flasher Connections

#5 Post by Jim Alton » Mon Jun 19, 2017 8:34 pm

How are you measuring the 2 Ω resistance?

To accurately measure resistances that low you need a Wheatstone bridge or a very fancy and expensive Ohmmeter.

I'd recommend you hook things up press the button or horn ring and measure the voltage drop across the brush on the steering column. It looks like the horn button/ring ground one side of the relay so you probably should connect the negative voltmeter input to ground somewhere near the steering column and the positive voltmeter input to the brush on the steering column or the 85 terminals on the relays.

The horn [flasher] button and hornring work through a relay so a voltage drop of a fraction of a volt (probably even more) shouldn't hamper reliable operation.
 
Jim Alton
Los Angeles County, CA
1958 Porsche 356A Cabriolet
1965 Porsche 911 Coupé
1966 Volkswagen Type 2
2003 Porsche 986 Boxster

Robert Vaughan
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Re: Steering Column Horn/Flasher Connections

#6 Post by Robert Vaughan » Tue Jun 20, 2017 8:07 am

Usually broad flat insulating spacers don't fail unless they are smashed. Look for a wire with failing insulation or a solder joint with a big solder blob. At 2 ohms some wire is touching the steering column. This isn't leakage through an insulator. This is contact.

Carl Luck
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Re: Steering Column Horn/Flasher Connections

#7 Post by Carl Luck » Thu Jun 22, 2017 3:52 pm

Thanks to all for the input. It sure looks like a unwanted connection between the upper copper ring and the column itself. I have put a insulative "sleeve" of the wire that exits the column for connection to the horn button all the way down to where it comes out of the column at the sleeve. Lifted the wire at the exit hole so it is not touching anything and the nearly short still exists. This may never be solved but I appreciate the ideas. I'm going with the assemble it all and see where we are. Thanks again.
 

Robert Vaughan
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Re: Steering Column Horn/Flasher Connections

#8 Post by Robert Vaughan » Thu Jun 22, 2017 6:10 pm

Before you assemble it and hide it for ever, take a macro photo of the area where the wire is joined to the slip ring. I have never seen one of these things, so I don't know what insulating material they used beneath the slip ring. I would suspect a solder blob or a frazzled wire near the assumed solder joint to the slip ring. Usually close visual inspection with un-aided young eyeballs will reveal short circuits in technology of this vintage.

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