Driving lights

[Jim Yergin]

In reviewing the wiring instructions for installing the optional driving lights and checking the operation of the switch for the driving lights, it appears that when the switch knob is pulled out, just the driving lights are turned on. When the knob is pushed in the driving lights are off unless the parking lights or the headlights are turned on then the driving lights also go on (because of the way the tail lights are wired into the switch). Is that correct?
Jim Yergin

[Joe Johnston]

In reviewing the wiring instructions for installing the optional driving lights and checking the operation of the switch for the driving lights, it appears that when the switch knob is pulled out, just the driving lights are turned on.

Yes

When the knob is pushed in the driving lights are off

Yes

unless the parking lights or the headlights are turned on then the driving lights also go on (because of the way the tail lights are wired into the switch). Is that correct?

No

Looking at the Electrical Manual for 55 & 56, both years show the power for the driving lights is sourced from terminal "A" of the Ignition switch not the headlight switch. In other words, no matter where the power is sourced the driving light switch is in the middle of the wiring (between the power source and the driving lights), so this accessory is only operational with the Ign switch on and the driving light switch pulled out. These are not what we call today "daytime running lights" that operate all the time. If you want that, the "parking lights" can be rewired to do so.

[Jim Yergin]

Joe,
Thank you for your reply. What I don't understand is the connections on the switch. There are three: power; driving lights; and tail lights. In the on position the power terminal is connected to the driving light terminal but not to the parking light terminal so I can see that the driving lights would be on. When the switch is in the off position the power terminal is not connected to the other two terminals but the tail light terminal is connected to the driving light terminal. That is why I assumed that if the tail lights are on (headlights on) then the same power would be sent to the driving lights and they would be on.
Jim Yergin

[Joe Johnston]

This is an excellent example of what can be learned by studying the Manuals.

Looking at the Electrical Manual diagram when the switch is mounted under the dash:

<terminal toward driver's door goes to Ign "A" terminal

<terminal toward firewall goes to lights

<terminal toward passenger door goes to the dash wiring harness 15274 connected by discarding the single connector and replacing with a double connector. An additional notation for this FEA-15274-A harness states that it is for the road lamp switch to rear lamp.

To me this means if this terminal and double connector is used, the tail lights would come on when you turn on the driving lights. This makes sense because of another diagram which shows how to connect the driving light switch and wiring so the headlights will be OFF when the driving lights are on for states that make such a requirement. In that scenario you would need tail lights to be ON because you would be driving with headlights OFF.

We have to realize years ago different states had different rules and regulations. No fed gov standardization. Even my 63SR could be "correct" with clear or amber front parking/turn signal lens depending upon the state the car was delivered to.

[Jim Yergin]

Joe,
I really appreciate your willingness to help me understand.
Until I checked the operation of the switch by checking continuity, I thought the same as you that the tail lights would come on when the driving lights were on but that is not how the switch works. When the driving lights are on the tail lights are not in the circuit. It is only when the knob on the switch is pushed in to the off position that the tail lights are connected to the driving lights and the power input from the ignition switch is not in the circuit.
I believe that, because the tail light input to the switch is "tapped" off the line to the tail lights, when the tail lights are turned on, power will run into the tai light terminal on the switch and then over to the driving lights.
I hope that someone who has the driving lights installed could confirm how they operate.
Jim Yergin

[Jim Yergin]

Here are pictures of what I believe to be my original Ford driving lamps switch. However I am confused by the connections. When the switch is off there is continuity only between the bottom terminal in the picture and the top right hand terminal. When the switch is in the on position there is only continuity between the bottom terminal and the top left hand terminal. Given those connections, I do not understand how the connections between the power source, the driving lamps, and the tail lights (as shown in the Ford installation instructions) work. Can someone help me understand them? Is my switch actually for some other application?
Thanks.
Jim Yergin