Soldering wires to turn signal switch


I need to put a new turn signal switch in my '52 merc, but before I can do that I need to solder the new wires on. How difficult is this and if you do it wrong could you ruin the switch?


Have you soldered anything before? If not - get someone with a little experience to do it. Too much heat can cause dammage - I know just about nothing about a 52 Merc but I do know about soldering - it’s easy if you know how to do it correctly - and easy to screw it up if you don’t.


The only way to hurt the switch is if you touch the iron to it and melt it. Here’s some options;

Good- Insulation displacement connectors. These do not require any soldering but they have some limitations. Basically a crimp connector where you place the two wires into the connector, fold the cover down and then press it together with a pliers. The insulation is displaced and the wire is pressed into a slot in the terminal. They are not good for weather exposure or vibration. Probably last the life of the car in the steering column.

Better- soldering with electrical tape to insulate. Twist the wires together. Allow the iron to fully heat for 5-10 minutes. Apply the iron to the wire and allow it to heat up for a few seconds. Now apply the solder to the opposite side of the wires from the iron. When the solder starts to melt, keep feeding it into the joint until all sides are soldered. Allow to cool and wrap with tape.

Best- soldering with heat shrink. Before joining the wires, slide a short length of heat shrink tubing up one of the wires. Keep it well away from the heat to avoid shrinking it prematurely. Solder the wires and allow to cool. Slide the heat shrink over the joint and apply heat to shrink. Almost anything can be used as a heat source from matches, heat gun or even the soldering iron tip. Just apply the heat evenly as it shrinks and avoid melting the wire insulation.

Super duper fanatic- heat sealing crimp connectors. These come in a number of form factors. A barrel connector is fine for this job. Their advantage is they offer a hermetic seal against moisture and corrosion. Strip wire ends, place in connector up to the insulation, crimp, apply heat with a heat gun and viola!

Any of these solutions are available at most home centers in the electrical aisle. Good luck!


Soldering shouldn’t hurt anything but it is not really necessary. Simply twist together the bare ends of the wires and wrap well with electrical tape. That simple method should serve you well.


the switch doesn’t have wires coming off of it there are just little round metal loops for the wires to go through.


Just loop the stripped end of the wire through the switch terminal and solder it. The switch is pretty robust and can withstand the soldering temperature as long as you don’t leave the iron on it for too long. Make sure the iron is up to temp before starting. The biggest mistake I see is when people try to start soldering before it’s fully heated. Then they have to keep the iron on the terminal too long and risk damage.


well, I’d say even if you don’t really know how to solder, this is a good time to learn- as it’ll come in handy later too, I’m sure. Personally, I prefer a small butane torch to most soldering irons. You can get one at your home center that even comes with different attachments (including a soldering tip); plus that way you can even heat shrink tubing with the same tool. It’s pretty handy.
Then what I did was take a bunch of old wires I had lying around, and practiced soldering those together till I felt competent.


Practice is a good idea. Also make sure you use a rosin core or flux core solder - the stuff you buy for soldering copper pipe has no flux in it. Also make sure you don’t move the wires until the solder has completely solidified - if you do you will get a “cold” solder joint that is prone to premature failure. You can identify a cold joint by it’s appearance - a good joint will look smooth and shiny where a cold joint will look “krinkled” - I’m sure a quick web search on soldering will result in photos of good and bad solder joints.

As I said before - soldering is easy if you know how but easy to screw up if you don’t.


Also be sure the metals to be joined are melting the solder rather than the pencil melting the solder (you do not need a large soldering gun, that’ll only do damage). You need sufficient heat for good wetting.

You might want to look on the 'net for basic soldering instructions. J-STD-001 or IPC-610D are good, but they’d be overkill.


You need sufficient heat for good wetting.

Can be said about other things too :wink:


Here is the step by step. After reading Safety directions with soldering iron, and having on safety glasses.

  1. Plug in the soldering iron to heat it up,(place it on something that wont burn)
  2. Strip the wire, and thread it thru the switch terminal hole and wrap the wire around the terminal one time.
  3. Apply flux to the terminal, and wire
  4. Dip the hot iron tip into the flux for a second
  5. Apply some solder directly to the tip of the soldering iron to load up the end with solder.
  6. Apply the soldering gun tip directly on the wire terminal, once the terminal heats up enough the solder will automatically flow from the
    iron to the terminal.
    Thats it.


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