controlling door locks

Folks:
I have a question regarding hooking up an aftermarket alarm/starter to control the power door locks.

Should I use the door lock wire directly, or should I use the factory alarm arm/disarm wire? It's said that the door locks can be controlled either way.

Is there any advantages in using the factory alarm arm/disarm wire? Would this indirectly control the interior dome light as well? For instance, when unlocking with the factory fob, the dome light and cargo light would illuminate and the parking lights would flash. It would be great if the factory arm / disarm wire triggers all of these functions.

2005 Dodge Ram 1500:
Power Lock = PURPLE / dk. green
Factory Alarm = PURPLE / lt. blue

Thanks,
-Ken

The factory arm/disarm will work the locks as long as your unit can do double pulse unlocking. As far as the other functions, it will do whatever happens when the key is turned in the driver's door cylinder to unlock.

You can also do all that with a 457C interface module from DEI...that will also bypass the factory immobilizer for remote starting if you go that route.

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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two

Chris:
My truck does not have the immobilizer, so I'm all set there. I got the remote starter portion working last night.

That's a good suggestion. I should check exactly what happens when I turn the key to unlock the door.

I have another question regarding resistor wattages:

Bulldog has a diagram on how to connect to the door locks which is a multiplexed-single-wire. It says to use 330 ohm to unlock, and 820 ohm to lock. However, it does not specify any particular wattage rating. Would 1/2 watts be enough?

Door wiring

My unit has the onboard relays (6-pin diagram).

Thanks,
-Ken

2005 Dodge Ram 1500

That has to be driving relays, since using those resistance values would supply very little current, at least not enough to drive actuators directly.

1/2W should be fine even in a worst case situation where full power were applied directly to it, so if you have 'em, go ahead and use 'em. You'd need to see what it's actually driving to find out how small you can get away with.

I'd guess you don't need that big a resistor, but you usually can't go wrong going bigger, unless it just doesn't fit.

Looked at that diagram further, since it uses the resistance values to control whether it locks or unlocks, there's probably a comparator circuit in there, using the resistors in a divider circuit, so I'm sure you could get away with the tiniest of resistors, as long as the value is accurate. Doubt it pulls much current at all.

1/2 watt resistors are fine for multiplex lock or arm/disarm circuits. If you wanted to use the arm wire, use 644 ohms for arm/lock, and 1565 ohms for disarm/unlock, and set the unit to do double pulse unlocking.

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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two

Guys:
Thanks for the quick responses and great information! I browsed thru the forum more and came across the following thread concerning whether to use the door wire or factory alarm to control the keyless entry.

Dodge Ram Keyless Entry Thread

It sounds like your suggestion of going with the arm/disarm circuit is the way to go.

Thanks,
-Ken
2005 Dodge Ram 1500
Westminster, MA