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Power locks giving me a very hard time!!

4.5K views 15 replies 8 participants last post by  bash64  
#1 ·
I know there are more threads than I can count about power locks on here, and yes I have searched! But I can't find anything pertaining to my particular problem. My car is a 1990 se hatchback and has power everything standard. When it comes to the locks we're talking about the part where I lock one side and the other side locks or unlocks respectively while you're in the car. All the linkages are fine and I have good wiring and all that other necessary stuff. But when both doors are locked and I go to unlock them from the inside only my passenger side will unlock both doors but it won't lock them back. The driver side won't lock or unlock the doors at all and it also kinda fights back (moves back and forth but won't do anything, kind of like its stuck in the middle of locked and unlocked). I've been searching for an answer for almost a year now but I haven't found an answer so is there anyone out there that can help me on this? I've tested the wiring and the switches and I've swapped the actuators and it does the same thing. I don't know how to test the actuators so they could be a possible culprit. Anybody that can help please speak up!:feedback: oh and if this is in the wrong section I'm sorry I haven't been on here in a long while.
 
#4 ·
I've tested everything that I can find in the FSM and I've even tried a different TCU for the locks. I'm getting power to both doors. If I have everything hooked up I can open my driver side door and sort of over extend it if that make sense and the doors will lock. I found a door harness so I'm gonna try plugging that in and see if it changes anything. Is there a way to test the actuators? From the testing I've done I "think" they're good :/
 
#5 ·
You can ohm it out. The fsm should give you those specs. The other idea is a little more dangerous and could fry them. But put 12v to it one way then switch it the voltage the other way. It should pop it open then when you switch it should close. All it is, is an electric motor so power spins it one way and the other when backwards. But keep in mind you could burn them up doing this trick.
 
#6 ·
I used a 9v battery to test them and they work movement wise but when I ohm the 3 wire plug I only get a reading in the middle of the travel ( like say they move 180° I get the reading at 90°) I'm assuming they're good. I tested for signal from side to side with a speaker and when I unlock the doors you hear the speaker "click" 2 times just like the relays in the TCU. So I'm 99.9% sure the wiring and power is good. This is becoming a pita lol
 
#7 ·
They just don't work under a load? Have you lubed the hinges and moving parts to cut the resistance. Mine dont always work but then they do. That's kinda last on my list. But this is really catching my interest. I have the actual book from Nissan on my 91. Should be the same as your 90 for the door locks I'll try to take a look tomorrow.
 
#8 ·
Everything moves freely and smoothly, if I have the drivers side actuator connected and I go to lock the door 9/10 it wants to fight back you can hear the actuator trying to force the lock to the unlocked position whether the door is shut or not. There's no response from the passenger door. The only time the passenger door works is when I unlock both doors from that side. I hope that made sense cuz that's the best way I can describe my problem
 
#10 · (Edited)
This is just a suggestion.

It sounds to me like your circuitry may have come into contact with a grounding point of some magnitude, or could have damaged internal parts. The next time you open up your door panels to have a look inside, start looking for any spliced wires or damaged connections/connectors throughout the door( both doors ). As simple as it may sound, sometimes you have to start with the most simplest, sometimes even odd/dumb sounding thing. From that point, start following the wires if you can locate them, into the hood to your fuse boxes and relays etc. and see if the lines/connectors are damaged along the way.

To my understanding, the circuitry is getting the power that it needs to activate, however when it needs to revert back to its former setting ( Open and close in this case ) , something is hindering its path. It could be that when it opens/closes the wiring moves with it and gets jammed or something of that nature that causes the fight back you've been experiencing 9/10 times. I'll do some research and hopefully it leads to fruition.

If Im not back , PM me. Let's get'er done. This has certainly gotten my attention.
Best of luck dude.
 
#15 ·
I've lived with wacky power locks on my '89 for years. Everyone knows the rule when they ride with me: don't touch the locks. Only the driver should lock or unlock the doors, both on the inside and with the key on the outside. If someone breaks the rule, I have to get out, use the key on the passenger side, manually lock and unlock the passenger door on the inside, and finally pray that my car settles back to letting me control things from the driver side. Sometimes, she literally fights me when I try to lock or unlock the door; the motor pushing back against me. And just to be sure, the last passenger out of the passenger side checks that the door is locked after I turn the key on the driver side. Just to be sure it locked.