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Guest Message by DevFuse

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RKE - Relays in doors or dash?

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1 reply to this topic

#1 MR_Loyale


    22 Years of Ownership. 94-16

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Posted 16 July 2013 - 11:30 PM

1993 Loyale Sedan FWD SPFI. I am doing the groundwork for a remote keyless entry (RKE) system so I can press a button on the key fob and have the doors lock/unlock.   As you know, the driver side door of the Loyale is considered a "master" in that opening with the key or moving the lock latch from the inside locks and unlocks the doors.  There is no actuator in the driver's door.  In order to accomodate my RKE system's lock/unlock feature, I need to put in an actuator and a resistive restive ground relay circuit so that I can trigger the lock and unlock with a negative pulse as that is what my RKE control module requires. Got all that? LOL.


Here is a video describing the resistive rest at ground circuit I am going to be using:




MY QUESTION:  I have a pair of wires already run through the side of the door, through the door wiring boot to inside the car. Would it be best to mount the relay set inside the driver door (there is a hot wire in there according to my Haynes manual) and use the wire pair for the control signal (max 250ma). This would be the wires connected to terminal 86 in the video above. The advantage I can see here is that only a very small current would be running through the two wires. Disadvantage is that the relays would be subject to lots of mechanical shock from the door being opened and closed.





Mount the relays under the dash and use the wire pair as power to drive the solenoid (probably 1-3 amps I am guessing though I haven't measured the amperage used when activating the solenoid).  This would be the wires to terminal 30 in the video. The advantage I see here is that the relays wouldn't be subject to the mechanical shock of the first option. Disadvantage that a much larger current will be running thorough the wires.


I am leaning towards the relays in the dash just for reliability but thought I would get opinions in case I missed anything.

Edited by MR_Loyale, 16 July 2013 - 11:32 PM.

#2 Subeast-EA81


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Posted 20 July 2013 - 11:46 AM

Relays under the dash for sure.  You can accidentally have a relay make contact under mechanical shock conditions (i.e. closing the door) and depending on how the relay is oriented, and wired will depend on which function it will operate. for example if the conditions are right it could cause the doors to unlock or vise versa.  And as for the length of run and suspected amp draw which most solenoids are are in the mA range, and if it more then that, its only for a short burst, not much time to overheat a wire if its just slightly undersized. hope this helps.

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