Chrysler Repair: when insert key to open doors it clicks back to lock, electrical resistors, memory seats

Question
hello,MR,Finston.
i have 1999 Chrysler t&c limited, and i am having issue with locks and alarm, i only have key to lock and unlock doors when i am trying to open the door with key it will go unlock and lock 3-4 times and finally it opens, some time lock will open and then alarm will go off and have to lock and unlock again, its from driver side if i do it from passenger side its not same, or from trunk, now i can unlock the door and lock it but alarm is not working, its sound to me some kind of electrical issue my memory seats don't work every time i sat on seat or get of i hear click sound from under the seat? looking forward for your advise in the past you have giving me detail info on changing evaporater and charging ac could not have done with out you , you are the best thanks nauman ashraf

Answer
Hi Nauman,
The chances are the problem is with the electrical contacts in the door key lock switch. There are two different electrical resistors in the switch, one is activated by the locking motion, one is activated by the unlocking action. A single wire carries the current from the body computer to the switch and a single wire carries the current to a ground return point on the body.
You could observe the electrical connection for the reliability of the reading by going to pin 45 of the natural color plug at the body computer which is located on the back side of the fuse box under the dash: unplug the plug, then attach an ohmmeter to the pin #45 and measure the resistance to ground when you turn the lock key in either direction to see if it is a solid reading of either 250 ohm or 1,500 ohms. It not then you will want to remove the door panel and spray contact cleaner on the internal switch contact to improve the solidity of the readings, and if ineffective then change the lock/switch itself. Let me know if you want to remove the panel to do that and I'll give you the steps.
Let's deal with the memory seat after the lock is fixed.
Roland
PS Thanks for the kind remarks.