I will be getting my fully restored original 1950 AM radio back from repair shop and will need to connect to power source. I know it goes to the ignition switch and to a prong that only gets power when car is on/key turned but how can I choose the correct prong if I do not have multimeter. Can I just test each with ignition off and radio on and the one that does not light the radio is the correct prong?

 

I know nothing about 50s wiring. GM used a yellow wire as a radio power feed in the later years. I have no clue if they did the same on the earlier cars.

Use a test light to find a fused power source that has power in both the run and accessory ignition position.

 

Both a multimeter and a test light are cheap enough and Harbor Freight, Northern Tool, even yer local chain parts store etc have both. They'll do fine for a hobbyist and are must-have tools for anything electric-related on your car. Keep in mind a 12v test light will work on your 6 or 8 volt 50, it'll just be dim.

 

Thanks. I think I may even have something I got for outlet replacement job I did. I beeps and lights up if you touch a hot line. Should do the trick. It is a voltage detector.

 

Pretty sure a voltage detector for household current will be useless in a automotive application.

Get a automotive test light. They are dirt cheap, and probably second only to a multimeter in overall usefulness.

Keep in mind, a self powered test light is not the same as a test light!!! Attempting to use a self powered test light as a voltage tester will result in a burned out tester.

 

A household tester is useless on cars. To me the test light is my primary tool for troubleshooting and the multimeter is secondary in overall usefulness.

 

A meter is far more useful due to the different ways it can be used, such as voltage, resistance, current, not to mention the added accuracy (a test light will light at around 6 bolts, abd will continue to light with increased voltage, right up until the bulb burns out). The only drawback to a meter is knowing how to use it and it’s added capabilities.

A cheap test light is about as easy as it can be to use, and will handle probably 90% of the diagnostic needs on these cars.

 

[QUOTE=matt69olds;1333116]A meter is far more useful due to the different ways it can be used, such as voltage, resistance, current, not to mention the added accuracy (a test light will light at around 6 bolts, abd will continue to light with increased voltage, right up until the bulb burns out). The only drawback to a meter is knowing how to use it and it’s added capabilities.

A cheap test light is about as easy as it can be to use, and will handle probably 90% of the diagnostic needs on these cars.[/QUOTE
i will stop into ace hardware tonight. Thanks.

 

It's for AC voltage and doubtful it will work with low-voltage DC, but you can try. Keep that test light in mind though.

Non-powered test light- used to detect voltage. Connects to ground and then probe connections to see if circuit is hot. Lights if there's voltage present.

Self-powered test light- used to detect continuity in a circuit and best used with no voltage present. Connect wire clip to one end of circuit, then probe other end. If it lights, the circuit is intact with no breaks or "opens" in the circuit. Useful for checking fuses and switches.

Multi-meter- used to check AC and DC voltage, voltage drop, resistance in ohms, any number of things. Very useful tool and reasonably easy to learn.

Plus I'm one who believes you can never have too many tools!😁

 

I should be all set. Now how do I use it to test ignition switch to find proper locator ion to connect my radio’s hot line?

 

Connect the black probe to a good metal body part (ground), use the red probe to check voltage at points that you can hook up your radio to a keyed on power source. Set the dial on the meter to the DCV 50 setting if your car is 12v or the DCV 10 setting if its 6. If the car originally had a radio, there should already be a connection for it.

 

With the instrument switch OFF-

Plug the RED lead into (+) jack, BLACK into (-) . Then set the switch to DC VOLTS, either 10v (for 6 and 8 volt systems) or 50v scale (for 12 volt systems). Put black lead probe to chassis ground and RED to the ignition switch terminals while moving the switch between OFF, RUN and ACCESSORY. You want radio power in RUN and ACC.

You'll soon get the knack of using the meter to troubleshoot both automotive and household electric issues.

Just remember when checking resistance (ohms) there must be NO VOLTAGE PRESENT on what you want to check. It will fry the ohmmeter section of the instrument.

 

[QUOTE=oldcutlass;1333174]Connect the black probe to a good metal body part (ground), use the red probe to check voltage at points that you can hook up your radio to a keyed on power source. Set the dial on the meter to the DCV 50 setting if your car is 12v or the DCV 10 setting if its 6. If the car originally had a radio, there should already be a connection for it.[/QUOTE

this is great. So appreciated. The radio is original but wire was connected to radio housing with inline fuse not car