How to kill door solenoids while driving?

[Brave Salmon]

I love the door solenoids I got from Autoloc. A push of the remote button and the door pops open. Works perfdct. Now, how do I kill the system so I don't mistakenly push a button at 70mph and lose a door? I can put in a relay to cut power to the remote control box if I can think of a signal I can use to trip the relay. Can't use key-on power because I would not be able to close the door while engine is running and be able to pop open the door. Aka, locked out! In my setup, it's a carb'd sbf with aod. No other computer stuff. So where do I get a signal to activate the relay?

Thanks..Tom

[RoadRacer]

don't know automatics, perhaps you can get signal from drive.. or mount a switch to handbrake

[Svtfreak]

I’d put door safety pins to manually lock them. It’s a good idea for any suicide door and damn near a necessity for a setup like yours.

[NAZ]

Since you only need the doors to open and close when parked how about a system enable while in park only or with the parking brake set only? A normally open switch that makes the circuit (closes) only when in the park position or only when the parking brake is engaged would energize the system when the car is in a safe mode (parked with zero speed). Would require some minor fabrication for a bracket and selecting an appropriate switch to interface with either the shifter or the brake handle.

If you don't have exterior door handles and are relying on solenoids to actuate the latches and you haven't already, you should incorporate some sort of locked or hidden manual method to unlatch the doors as any loss of power, short, open, or other failure will leave you unable to get in.

[Fixit]

Two ways to do it...
Depending on the gear shifter you're using, you may be able to stack a 2nd "neutral safety switch" on it, and use this 2nd switch to drive a relay make/breaking power to your lock solenoids. (Don't try and run the current for the solenoids through a dinky micro-switch, it'll melt).

Or, a little rewire job using your existing neutral safety switch would do the job. It'd take two relays - #1 to make/break the circuit to the starter solenoid (as it is now), #2 to make/break power to the lock solenoids. When the car is in P or N, the starter & locks would work, any other gear they won't. (you're splitting a single switch into doing two functions.

More details on the shifter and NSS are needed...

[Jeff Kleiner]

...Or, a little rewire job using your existing neutral safety switch would do the job. It'd take two relays - #1 to make/break the circuit to the starter solenoid (as it is now), #2 to make/break power to the lock solenoids. When the car is in P or N, the starter & locks would work, any other gear they won't. (you're splitting a single switch into doing two functions.

My thoughts exactly!

Jeff

[JimLev]

Like Fixit suggested but with only one relay that had 2 sets of contacts...common, n/o, and n/c.
One set to the starter solenoid and the other for door power interrupt.
Only one relay to mount and wire.

[Brave Salmon]

makes sense. the neutral safety switch is the Lokar standard switch. Problem I see is that it passes +12vdc through the switch when its made (neutral/park) but that's only when the key in in the start position. The rest of the time that signal (blue wires) floats somewhere near ground potential. Its not enough of a ground to fire the relay. If the blue wires were actual ground when floating, it would work. If I use a the +12 to fire the relay it would only work in the start position. man, getting old is a *****. I used to be able to do this in Boolean algebra with my eyes closed. Any ideas are welcome. I agree that this is important and btw, I will be using a mechanical door release from the trunk in lieu of a power failure. thanks guys.

[NAZ]

Tom, if you already have a relay for the door latch solenoids you don't need more relays. When you park the car you will probably have it in "P" and that's where you want a micro switch as an interlock. The switch will complete the ground circuit on your door solenoid relay coil when the trans is in park. You should have already provided circuit protection on the hot side of the door relay coil and I suspect the hot side of the coil is energized from your remote receiver for a few seconds when you command it with the remote. The typical automotive type 20/30A relay coils are very low current so no need to have a bulky high amp switch. A place like McMaster-Carr or Dell City will likely have a selection of switches to select from. You just need to get a bit creative on how to mount the switch but this should not be a big deal. Even something as simple as a spring loaded plunger type normally open switch similar to a brake light switch that contacts the trans linkage when in the park position would serve as an interlock. When the plunger is depressed the switch make the ground contact on your solenoid relay and when the relay is commanded the doors open. If the relay is commanded in any mode except park the relay coil won't be energized and the doors remain closed.

[Fixit]

Had a few minutes and CAD'd up a couple of diagrams.
In any selection other than P or N, the starter and locks will be disabled.

NSSclosedPN.pdf is a circuit using a NSS that is closed when the shifter is in P or N
NSSopenPN.pdf is a circuit using a NSS that is open when the shifter is in P or N

Your Lokar shifter may already have a micro-switch installed that has both N.O. or N.C. terminals on it. Depending on how Lokar trips the switch, you could change the connection to suit.

(Preference would be to use the NSSopenPN circuit. It will only be energized when the car is running, and is a somewhat "Fail Safe" design... if the relays fail you can start or unlock the car.)

NSSclosedPN.pdf
NSSopenPN.pdf

[Brave Salmon]

Had a few minutes and CAD'd up a couple of diagrams.
In any selection other than P or N, the starter and locks will be disabled.

NSSclosedPN.pdf is a circuit using a NSS that is closed when the shifter is in P or N
NSSopenPN.pdf is a circuit using a NSS that is open when the shifter is in P or N

Your Lokar shifter may already have a micro-switch installed that has both N.O. or N.C. terminals on it. Depending on how Lokar trips the switch, you could change the connection to suit.

(Preference would be to use the NSSopenPN circuit. It will only be energized when the car is running, and is a somewhat "Fail Safe" design... if the relays fail you can start or unlock the car.)

NSSclosedPN.pdf
NSSopenPN.pdf

Whoa, this is what I was looking for. I will try and hook it up this weekend and let you know how it works. Thank you so very much.

[Fixit]

Like Fixit suggested but with only one relay that had 2 sets of contacts...common, n/o, and n/c.
One set to the starter solenoid and the other for door power interrupt.
Only one relay to mount and wire.

This is also a possibility, but finding a readily available 2PDT 12v/30a relay (not of the industrial control base/socket type - I.E. IDEC) isn't easy. You can get the Bosch "Ice Cubes" anywhere.

[JimLev]

This??
https://www.amazon.com/uxcell®-JQX-1...+relay+12v+30a

[Fixit]

That would do the job, and save a little space!

[Brave Salmon]

Guess what? I had the best solution right in front of me all along. When I used the Lokar shifter I had to eliminate the connections to the factory neutral safety switch on the transmission. Turns out that pins 3 and 4 of the stock switch make in neutral/park and that gives me a nice hard ground I can use to switch on the remote controller box when in neutral/park and turn it off in any drive mode. Goes to show if you beat on something long enough you will find the solution. Thanks again to all the input we received and hopefully others will learn if they face this same issue.

[NAZ]

Great! One more problem you can check off the list.

[BillGardner]

If you have an electric fuel pump, you can run a wire from the power on that pump output to trigger a relay. When the pump is off, the relay makes contact with 87A automatically, but when it's energized by the fuel pump, it breaks that contact. just leave 87 open.

[gumbya55]

I have the same setup, and all you have to do is get your power source from the back of the ignition switch (don't remember which terminal) but one of the terminals when the key is on there is no power to that, so you can't activate the relay...easy