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Need a diagram for 12V vehicle switch

Dietmar

Jun 29, 2016
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I have bought a switch from Ford to switch on external lights. My vehicle is not fitted with fog lights, but has a dud switch with a cover on. Removing that cover I found a plug connected to that dud switch. It has 4 wires connected. Two for the illumination of that switch when the lights are turned on and the other two probably to connect to fog lights which don't exist. I have cut last mentioned wired to connect to my external lights.
The problem I have, is that if I press the switch and by keeping it pressed in, the lights turn on. When releasing the switch, the lights turn off. In other words the lights do not stay on when pressing that switch.
I don't know how the switch should work!
Can I build a gadget with a relay to keep the lights on when the switch is pressed and to turn off again by pressing it again?
The switch should power 12V with lights 50 to 60 watt.
183102147_2001-2012-ford-escape-fog-light-switch---motorcraft-.jpg
 

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Harald Kapp

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Obviously you have a momentary switch (push button).
The easiest solution is using a switch with on-off positions.
 

Dietmar

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Obviously you have a momentary switch (push button).
The easiest solution is using a switch with on-off positions.

Hi Harald
The switch I bought is a Ford Fog Light switch. Why would they sell a push button switch? Can it be modified?
 

Harald Kapp

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Why would they sell a push button switch?
They possibly have a controller somewhere that controls the lights. The pushbutton is used only to give a signal to the controller. Just a guess.
I doubt it can be modified.

You could use the pushbutton to control a T-flip-flop (T for toggle). A schematic including a debouncer is described here. this circuit is admittedly rather complex but illustrates the principle.
This circuit using relays may be more in the direction you're seeking. Plus you can use a relay with additionla contact to control your gadget by the surplus contacts.
 

Dietmar

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Thanks Harald, it makes more sense now. The circut relays is an easier option. As I am still a learner of electronics. Where do the lights connect to the 'Relay Toggle Switch Circuit Diagram'?
 

Harald Kapp

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There are contacts A,B and C shown in the diagram for each relay that can be used for whatever you want to connect (observe the contact ratings, though).
 

Dietmar

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There are contacts A,B and C shown in the diagram for each relay that can be used for whatever you want to connect (observe the contact ratings, though).
Thanks again Harald. Will build the circut soon.
 

Dietmar

Jun 29, 2016
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Thanks again Harald. Will build the circut soon.
Hi Harald
Past weekend the 8-pin relays were not available in our shops. I have bought 12v automotive 5-pin relays and build different diagrams I found on the web, but they did not work. Also searched the web, but could not find a diagram to power lights with a push on/off switch.
I'm back to square one. Could you please help me with a 5-pin diagram?
 

Harald Kapp

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You can use the same diagram, just don't use pins A, B and C then you see 5 pin relays.
Connect the coil of a 3rd relay in parallel to the coil of RL2. Do not connect the contacts of the 3rd relay as on relay 2!
Instead connect +12V to the common contact (C) of the 3rd relay, use pins A and B to connect a load (e.g. light) to ground (0 V). That way the load will be turned on and off by pressing the pushbutton.
 

Dietmar

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Thank you. I have redrawn the diagram, is it correct?
I have also marked the Relay numbers.Diagram.jpg
Maybe I must swop 85 and 86 around.
 
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Harald Kapp

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This is mainly what I mewant, with one exception: the center contact of RL3 need to be connected to +12 V permanently, not via the pushbutton. Compare to RL1's center contact. Otherwise RL3 will switch, but as you release the pushbutton, the light will be off despite the contact of RL3 being closed.
 

Dietmar

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Thanks Harald. I have changed and connected it as sketch below, but attaching the 3rd relay to 12V, the light goes on. Please help?
Diagram.jpg
 
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Harald Kapp

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This is not what I tried to explain.
RL1 and RL2 are not connected as in the diagram in post #10.
RL3 looks good.
 

Harald Kapp

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Compare your diagrams.
In post #10 the pushbutton goes to RL2, in post #12 it goes to RL1.
 

Harald Kapp

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Looking closer I see that you made a few copy mistakes from the original. Also, I noticed you can omit relay RL3. The result should look like this:
upload_2016-7-22_13-24-29.png
 

Dietmar

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Thanks again Harald, for spending time with me on this project.
When connecting RL1 to 12V, the light comes on, but very weak. Pressing the switch, makes the light bright, but when releasing it, the light goes weak again.
 
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Harald Kapp

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When connecting RL1 to 12V, the light comes on, but very weak. Pressing the switch, makes the light bright, but when releasing it, the light goes weak again.
Check your wiring. I'm sure it is not fully equivalent to what the diagram shows. It sounds as if the lights are powered through a resistance, which in this circuit could only be a relay coil.

The lights other end needs to be connected to ground (not shown in the diagram).
 

Herschel Peeler

Feb 21, 2016
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I have bought a switch from Ford to switch on external lights. My vehicle is not fitted with fog lights, but has a dud switch with a cover on. Removing that cover I found a plug connected to that dud switch. It has 4 wires connected. Two for the illumination of that switch when the lights are turned on and the other two probably to connect to fog lights which don't exist. I have cut last mentioned wired to connect to my external lights.
The problem I have, is that if I press the switch and by keeping it pressed in, the lights turn on. When releasing the switch, the lights turn off. In other words the lights do not stay on when pressing that switch.
I don't know how the switch should work!
Can I build a gadget with a relay to keep the lights on when the switch is pressed and to turn off again by pressing it again?
The switch should power 12V with lights 50 to 60 watt.
183102147_2001-2012-ford-escape-fog-light-switch---motorcraft-.jpg

I agree with Harold. It looks like the switch is designed to work with an electronics module. You could confirm this by browsing a manual for your car at your local auto parts store.
.
 

Dietmar

Jun 29, 2016
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Thanks to all. I 've got it working. There was a mix up with the N/O and N/C that were switched around, although I have tried it like that. Removing the resistant at the neg/ground made it work.
Appreciate all help.
Thank you
 
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