Neutral Safety Switch

Stephenorf

Senior Member
I have a 1959 Mercury Monterey that I've been working on. It has cranked/started with no problems since I started working on it (off-and-on couple of years). Yesterday, I turned the key to 'Start" and it turned over a couple of times and then nothing.

1: Jumped from the POS side of the starter solenoid to the "S" terminal and the engine cranks over like normal (Proves out that the battery, solenoid, starter and related wires are in good working order)

2: Disconnected and reconnected the two-prong lead from the NSS with the red/red-black wires to make sure there wasn't a bad connection. The prongs/sockets look clean. The connection came apart with minimal effort (I've encountered these types of connection with so much corrosion that they would not separate). After re-plugging in the dual prong leads, still nothing. (Kind of proves out that the connection between the NSS and the engine harness is good)

3: Disconnected the red/red-black lead from the NSS and jumped the ends on the engine side of the harness together. Turn the key to Start and the engine cranks like normal. (Proves out that the feed between the NSS and the solenoid/ignition switch are in good working order.)

Seems the problem must be the NSS

4: Removed the NSS and observed no cracks in the Bakelite housing and no cracked/frayed/corroded wires. I 'bench tested' the NSS with an ohm meter and the connection between the contacts and the plug-ends have good continuity i.e. zero resistance. (Proves out that the NSS is in good working order.

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5: Next I jumped the connectors on the inside of the NSS and plugged it back into the harness. Turn the key to Start and the engine cranks like normal.

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Uereka - When I was attaching the alligator clip to one of the copper tabs I noticed it move. Come to find out the copper contact is loose. It isn't crimped down properly with the factory rivet, allowing a loose connection between the rivet and the copper contact which allows an open circuit between the contact and the wire lead. Tested and confirmed with my ohm meter. Open circuit. If I wiggle/move the tab the circuit closes.

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Question: Is there a good way to mash the factory rivet in order to tighten the connection between the housing and the copper tab? Or...drill out the existing rivet and use a rivet tool to put in a new pop rivet? Seems like if I can just tighten the contact the problem will be solved. I'm a little nervous about cracking the Bakelite housing.

Thoughts?
 

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  • 1959 Mercury Monterey NSS Jumpered.jpg
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Solder, put the solder iron on the rivet head with just a touch of resin, as the resin starts to smoke apply a touch of solder. If the looseness is on the wire end of the rivet that will not help. The cause of the issue is heat. Over the years the current draw caused the areas where wire/rivet/contact to heat up. That causes the Bakelite to break down, thus to loose fitting.
 
Solder, put the solder iron on the rivet head with just a touch of resin, as the resin starts to smoke apply a touch of solder. If the looseness is on the wire end of the rivet that will not help. The cause of the issue is heat. Over the years the current draw caused the areas where wire/rivet/contact to heat up. That causes the Bakelite to break down, thus to loose fitting.

Hmm...I wonder if I should solder all the contacts. Seems like if one is loose, eventually they will all loosen up? I don't doubt that the Bakelite has broken down over the years, and that would explain why it is just now becoming an issue. When I observe the NSS, I don't see any signs of excessive heat or discoloration on the contacts. 66 years of wear and tear, who knows what other components are on the verge of wearing out.

BTW...the looseness is on the contact side of the rivet. So your advice should be good for a fix.

Thanks!
 
Closing the loop on this one.

I soldered the contact as Ford blue blood suggested. Solder weld is good and strong.

After reinstalling the NSS, the car cranks like it should.

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  • 1959 Mercury Monterey NSS Fixed.jpg
    1959 Mercury Monterey NSS Fixed.jpg
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