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Old 04-07-2021, 09:27 PM
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Jack 1957 Jack 1957 is offline
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Location: Strongsville,OH
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I need to replace the original exterior door switches. The CTS had electronic touch pads rather than mechanical door handles. The originals (Pictured split open on the right) were too big to use so I need to replace them with the smaller momentary push button switches
The problem is, the original performed two separate functions. Most likely when pressed the switch activated the door latch and also activated the drop down feature for the side window.

After studying the printed circuit on the original, it was clear that the engineers wanted these two circuits to remain isolated from each other while at rest. Only to be connected when the button is pushed.
In order to get function without sacrificing form, I needed to separate the switch from the actuator.n I'll use a 16mm momentary push button mounted in the mirror stands, then a couple relays inside the door to keep the two circuits separated unless activated.


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This is what I came up with. Typically, a relay is used to convey a heavier load on the power side (+) but in this application the switching is done by connecting or disconnecting the ground (-). You can see in my crude diagram below that there is 12v+ going into the relay coil, through it, and to ground-. This activates the coil creating an electromagnet which pulls the contact across from it and completes the circuit. The 12v+ that activates the magnet never comes in contact with anything else. The wires connected to the other side are isolated and can be either positive or ground. Whatever is needed. I used two separate relays so that the two ground feeds never come in contact with each other unless the button is pushed and connects both of them to chassis ground.



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This is the new rig that will replace the original touch pad.


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Button locations on both sides. Discrete but easy access.


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Both mirrors finished and installed. The rest will be tied in inside the door.


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Last edited by Jack 1957; 04-07-2021 at 09:42 PM.
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