door lock

[onechou2304]

Hi people,
is it normal (for a 91 NSX european) that when you close the left door (driver) with the key that passenger doesn't lock? there is no centralization on 91 NSX? you should manually locked doors?
Is there a fuse to check? or something to do?
best regards
PS: I have other trouble (maybe no links beetwen them); for example the trunk button on the panel door doesn't seem to work either

 

[drew]

Do both sides lock with the interior lock and/or keyless? If so, then your exterior door key switch is bad...

As for the trunk. Check your glove box for the "ON/OFF" rocker switch. If OFF, click to ON and try your door Trunk switch again.

 

[onechou2304]

Do both sides lock with the interior lock and/or keyless? If so, then your exterior door key switch is bad...

As for the trunk. Check your glove box for the "ON/OFF" rocker switch. If OFF, click to ON and try your door Trunk switch again.

thanks Drew, I will do the test, butin my mind, I find the switch in the glove box and it doesn't change anything at all.

 

[onechou2304]

I just try; it doesn't work.
sitting in the car, driving, when I push the "lock down" button, nothing happens.
I stop the car, try to turn the key in the driver door, It lock only this door; the passenger stil unlock.
I use the switch in the glove box; and the button open trunk in the panel door; it doesn't work; but I can open the trunk with the key.
Any ideas? usual default?

 

[Heineken]

Sounds like the whole lock/unlock mechanism isn't working. Have you checked the repair manual for fuses and tests?

 

[onechou2304]

Sounds like the whole lock/unlock mechanism isn't working. Have you checked the repair manual for fuses and tests?

yes, i think it is N°35 fuse ( 20 A) in the main relay box. i change it yesterday but no change

 

[Old Guy]

Was the #35 fuse burned open when you replaced it? If it was, that would explain why neither the trunk or the central lock system works. The trunk and central lock system are the only tow items supplied by fuse #35 (on North American market NSXs). Failed fuses are rarely ever the problem. They are just a symptom of some other problem (a short circuit). If the #35 fuse was burned open chances are the replacement fuse is also burned open and you have a short circuit someplace.

If the replacement #35 fuse is OK, then you need to carry out the input check for the central lock unit as described staring on page 23-256 of the 1991 service manual.

 

[onechou2304]

Was the #35 fuse burned open when you replaced it? If it was, that would explain why neither the trunk or the central lock system works. The trunk and central lock system are the only tow items supplied by fuse #35 (on North American market NSXs). Failed fuses are rarely ever the problem. They are just a symptom of some other problem (a short circuit). If the #35 fuse was burned open chances are the replacement fuse is also burned open and you have a short circuit someplace.

If the replacement #35 fuse is OK, then you need to carry out the input check for the central lock unit as described staring on page 23-256 of the 1991 service manual.

Thanks Old Guy for your answer. To be honest, the fuse was partially burned (?!) so I change it. When I test the centralisation yesterday, first time I pushed the"lock button" on the driver panel door, I heard a very little/light noise (1 or 2 secondes)...and after..something.
Is the power door lock control unit a usual failure on the NSX?
Best regards

 

[Heineken]

Certainly not a common fault.
Have you had a look at page 23-256 of the 1991 service manual yet? :smile:

 

[onechou2304]

Certainly not a common fault.
Have you had a look at page 23-256 of the 1991 service manual yet? :smile:

yes, the trunk and the lock door are on the same fuse (N°35 of 20A).
i will buy new fuses tongue
and I will disconnect the "button lock door" left and right and the "trunk button" and try to find which of doesn't work...
I have an idea: i think there is maybe some water/humidity in the passenger door....
How can I mesure the "continuity" between to points?

 

[Heineken]

Ah, that's good to hear :biggrin:

If there's moisture in the doors, carefully remove the inner door panels and check behind the plastic sheet. If yes, let it dry out sufficiently before continuing the analysis.
Continuity should be checked with a "Continuity Checker" or in case of these rather crude circuits also with a "Test Light". A Multimeter can be used, too, simply measuring the resistance between two test points (should not be more than 1-2 Ohm).

 

[Old Guy]

The power door lock control unit has electronics in it; but, the trunk lock system has no electronics in the system. The trunk lock system is very simple and as long as the valet switch in the glove box is set correctly (and has not become disconnected ) your problem is likely loss of 12 V DC power.

Moisture in the doors might be a problem; but, the switches and connections are normally protected from moisture by a plastic barrier. Your comment

first time I pushed the"lock button" on the driver panel door, I heard a very little/light noise (1 or 2 secondes)..

suggest that the problem might be in the lock motors which are in the latch and not directly protected by the plastic barrier. I suggest that before you disassemble the doors you do the input checks as described in the service manual. The input tests will tell you whether you have a problem with the lock motors. You will need a multimeter to do those tests (measures both voltage and resistance). If the tests indicate a problem, then you will need to trace down the location of the problem. Gradually disconnecting everything on a problem circuit and testing each time can help you locate the source of the problem. To do this, you need a separate document called the Electrical Trouble Shooting Manual which provides a map of how everything is connected in the car (the service manual does not have all the information). [MENTION=30613]Heineken[/MENTION] may be able to help you with the trouble shooting manual. If the problem is a short circuit in the wiring harness that can be a major problem to find and repair. Depending on where the problem is you may need to remove a lot of stuff (the dashboard) to get to the repair location. If the input tests indicate that everything is OK then disconnect the power lock unit and see if the fuse stop burning up. If the fuse stop burning up then the problem may be in the power lock unit which may be repairable or can be replaced.

 

[Heineken]

Checked my books and found the description of the Power Door Locks in the 1992 ETM (Electrical Trouble Shooting Manual), please have a look.

 

[onechou2304]

Checked my books and found the description of the Power Door Locks in the 1992 ETM (Electrical Trouble Shooting Manual), please have a look.

Marvellous Heinken!
thanks for the explanations.
I tried something:
change the fuse N°35.
turn the key in the cylinder door driver; the 2 doors locked.
turn the key to open; only the driver door open and the passenger door stay lock; and the fuse burns. I think there should be a trouble with passenger lock (maybe due to humidity).I will try to dismantel the panel of the passenger door.

 

[Heineken]

Very good! We're getting somewhere, it seems :smile:

When removing and especially when re-attaching the door panels be very careful with the mounting screws. The plastic mounting tabs break off very easily - tighten them only very little (I broke one when I loaded the panel into the trunk).
In case they broke (or more likely, are already broken) consider this: http://www.nsxcb.co.uk/entry.php?2661-Plastic-Repair

 

[Old Guy]

If you check the wiring diagram in the service manual, you will note that the passenger and driver side lock motors are connected in parallel. If the driver side door is getting the lock and unlock commands the passenger door is also getting those commands. The fact that the driver's door unlocks; but, the passenger door remains locked and the fuse burns out suggests one of two things, something in the passenger lock motor is shorting out during un lock or the latch mechanism is jamming internally preventing the latch from moving and causing a high lock motor current which blows the fuse. It is also possible that when you go to unlock the passenger door one of the two switches in the latch mechanism is briefly shorting to ground.

If you unlock the passenger door with the key does it unlock smoothly? If you operate the lock knob on the passenger door does it operate smoothly? If not, I suggest trying to spray some silicone oil into the latch mechanism to see if that improves the operation and then see if the fuse still blows when you try to unlock the doors. I give this a low probability of being successful; but, it is easy to try.

The lock motor and the lock switches are internal to the latch mechanism and are not serviceable (although I recall that @Honcho was going to experiment with modifying his latches so he may be able to advise). The repair according to the service manual consists of replacement and the list price for the replacements are about $900 each US $. So, you will want to carry out the tests for the latch as described on page 23-258 of the service to confirm that the problem is in the latch rather than just order a replacement.

 

[drew]

Take a bad internal door lock seriously. It is a major incident if it fails and the door cannot be opened.

 

[onechou2304]

I do some new test today.
New fuse.
use the key on the passenger door; it lock and open this door; and I heard a litte sound coming from the glove box.
use the key on the driver door; it lock and open this door; and I heard a litte sound coming from the glove box and from the interior of the door (soud taht I didn't heard in the other passenger door). the driver button lock panel door close the door but impossible to use to open.
And the fuse is hafly burn!!! not complete burn!! it's the third one ;-))

 

[Old Guy]

The power door lock control unit is located in the area behind the glove box. I expect that the lock control unit has internal relays that operate the lock motors and the "little sound coming from the glove box" might be the sound of the relays opening and closing to lock or unlock the doors. I am always outside of the car when I lock or unlock the car so I have never noticed a noise. If that noise sounds like a ''click - click' , that noise might be perfectly normal.

You should stop testing by installing fuses and then burning them out. You have confirmed that there is a problem and if you continue to replace fuses and try different operations at some point you may cause additional damage. Based upon what you have told us so far, you have two logical places to start doing further checking. Either remove the door liner to check the passenger side door latch mechanism to check the operation of the lock motor and switches or remove the glove box to get access to the power lock control unit and door lock control unit connector to do the input tests described in the service manual. My recommendation is to start by testing at the power door lock control unit. You can get access to it with less risk of damage to plastic body parts and if necessary you can do most of the functional checks of the door latch lock motor and switches from that location (you can't access the passenger lock knob switch from that location).

 

[Honcho]

The lock motor and the lock switches are internal to the latch mechanism and are not serviceable (although I recall that @Honcho was going to experiment with modifying his latches so he may be able to advise). The repair according to the service manual consists of replacement and the list price for the replacements are about $900 each US $. So, you will want to carry out the tests for the latch as described on page 23-258 of the service to confirm that the problem is in the latch rather than just order a replacement.

I gave up on my door lock weight-reduction project because I discovered that the internal motor and switch are integrated into the housing by press-fit metal into plastic. I was too scared to crack the plastic trying to remove them, since none of these internal components are available separately. A more adventurous person might be able to fully remove them, but even then, I'm not sure how they would get the parts back together again.

 

[drew]

Is the door unlock actuator an actual motor (the visible one) or a solenoid?

[MENTION=37562]onechou2304[/MENTION] it is time to get a multimeter, start testing, and documenting your results.

At this point, I would start tearing down the door. At least take off the door card at a *minimum* until you get this resolved.

Do some testing, but it appears that the removal of the door lock mechanism to bench test is in your near future, which is a fair amount of work.

What you don't need is the door lock to fail and you will be in a world of hurt. If you are not carrying around any passengers, I would remove both the seat as well as the door card.

 

[Old Guy]

Is the door unlock actuator an actual motor (the visible one) or a solenoid?

@onechou2304 it is time to get a multimeter, start testing, and documenting your results.

At this point, I would start tearing down the door. At least take off the door card at a *minimum* until you get this resolved.

Do some testing, but it appears that the removal of the door lock mechanism to bench test is in your near future, which is a fair amount of work.

What you don't need is the door lock to fail and you will be in a world of hurt. If you are not carrying around any passengers, I would remove both the seat as well as the door card.

On two wire lock actuators the actuator is typically a motor which is how polarity reversal gets you the open and close operations. Solenoids which typically have unmagnetized ferrite cores only generate a pull in force regardless of the energization polarity. You can build a lock actuator using solenoids; but, then you need separate open and close solenoids - a 3 wire device. The electric motor likely has a better torque / force versus current characteristic than a solenoid.

That said, the fact that the lock motor is a 'DC motor' may be key to [MENTION=37562]onechou2304[/MENTION] 's fuse blowing problem. As long as the motor is rotating it generates something called a back EMF which reduces the current flowing into the motor. If in the opening operation something is jamming causing a premature hard stop on the motor the motor current will go way up which is what may be popping the fuse. The power lock controller typically has an internal timer which applies 12 v to the motor for just long enough to get it closed or open; but, short enough to prevent it from the blowing the fuse. If the lock mechanism is jamming the motor at the start of the unlock cycle then the current may be staying high for long enough to blow the fuse.

It is also possible that the problem may be inside the actual lock motor and that the brushes are jamming when it rotates in the un lock direction. From @Honcho 's photograph, it looks like the actual motor might be accessible so may be serviceable if the problem is inside the motor.

To re enforce @drew 's point, you really need to determine whether the problem is in the latch mechanism which could be an early indication of latch failure (a very bad thing unless you plan to turn you car into a racecar where you get in and out through the window) or is in the electric motor or a wiring problem which is more of an inconvenience.

 

[onechou2304]

hello everybody.
I am very happy today because i can solve one of my problem: the trunk!!
Button door paneldoesn't seems to work. during a vaccum session, I find a blue plug not connected . I plug it and the trunk button work perfectly... so strange...I can imagine how it unplugged?

 

[onechou2304]

i hope there is no multipexing on a 1991 car because maybe it was unplugged intentionnelly to cover another issue...

 

[Heineken]

Maybe someone tried to solve the problem with the fuse and unplugged it - then forgot to re-connect?