2000 Cavalier Z24 remote door lock problem

[ago]

My 2000 Z24 has a strange problem with the remote door locks.

I can lock all doors with the remote, however when I press "unlock", the only door that unlocks is the passenger door. Also the remote trunk release is also not working.

The receiver unit (wherever it is) is receiving the signal from the remote, as I can see the daytime running headlights flash (and hear the relay in the fusebox), everytime I press unlock or lock on the remote. Same thing for the trunk release button.

Therefore to sum up the problem, the driver's door does not unlock (only locks) and the remote trunk release does not function.

Any ideas ?

Is there a common connector that is used for driver door unlock and trunk release ?

Thanks for any help (or diagram if possible),

ago

[tbill]

does the drivers door unlock with the power door lock button in the car? and does the trunk open with the button in the car?

[ago]

tbill,

The drivers door unlock with the power door lock button in the car does not work either.

Therefore unlocking the driver's door with either the remote, or the inside power lock switch both fail.

There is no inside remote trunk release on this car (only on the remote), as it is an option as specified in the owner's manual.

What do you think ??

Thanks,

ago

[tbill]

i could be wrong on this, but i think there is a 'drivers door unlock relay', it is either under the drivers seat, or behind one of the side kick panels.

also, look at the trunk latch [inside the trunk], there may be a 'valet' switch, this is used so the trunk can't be opened unless you have the key, it may have been 'hit' at some point disableing the remote release function. it may even be a bright orange sliding type lever on the latch. [hard to remember how all of them are set up, they seem to change year to year].

if i think of it, i'll look for a wire diagram when at work tomorrow [i work for a chevy dealer].

[tbill]

ok, i did some checking today, there isn't a drivers door unlock relay like i thought it uses a lock/unlock relay for both doors [from the diagram i looked at]. from the one schematic i looked at, it looks like the BCM and the RFA are one unit [body control module/remote function actuation]. this may be a case where it's worth the time to have a dealer hook up a scanner and see if the key fob input is making it to the BCM and if the BCM is outputting the proper command. from what you said about how the RFA and the switches are working, i wonder if you have a BCM issue? also looks like the trunk open option on the key fob is a direct function of the BCM, as in, no relay, push the button, and the BCM sends voltage to the trunk release solenoid to open the trunk.

[ago]

tbill,

Thank you so much for your informative reply. I really appreciate this.

Should I start perhaps with measuring voltage at both solenoids ?

What voltage (+/-) is fed to the driver door solenoid for lock/unlock ? And what about the trunk lock solenoid ?

If no voltage is present at either one, wouldn't that confirm a BCM problem ?

Thanks,

ago

[tbill]

i believe you should get battery voltage at the respective solenoid connector being tested. i suppose it could be possible that the door lock actuator and the trunk release solenoid both crapped out, it wouldn't be out of the realm of possibility. i have to assume the lock/unlock relay is working due to the passenger door unlocking. another thing that may be an issue is wiring itself, i neglected to check where the relay was located, and if there were any common splices in the wiring, and if there was common splices, if they were located in a 'high moisture' area [venture/montana/silhouete[sp?] vans have water leak issues, and the wire harness under the carpet gets wet and splices corrode, usually affecting door lock operation].

let me know what you find voltage wise, and i'll see what else i can come up with depending on what you find.

tbill

[ago]

t bill,

There is only one wire going to the trunk solenoid, so I measured the voltage there while connecting the ground lead of the voltmeter to car chassis. No voltage present while actuating the trunk release on the remote.

Furthermore, on the driver door solenoid there are 2 wires, orange and brown. -12v there when locking (which was working), but no voltage when unlocking...which is the problem.

I assume that +12 volts is sent to the orange with ground on the brown lead when unlocking, and then the voltage is probably reversed for locking (that is ground now on the orange, and +12v on the brown). That is my guess.

I am beginning to agree that this may be a BCM problem. Unless there is a connector between the solenoids and the BCM which may be in question.

Would you have any idea where the BCM can be found on a 2000 Cavalier Z24 ? Under the dash ? Near what ?

And any connectors on the way ?

Let me know what you think...and thanks again.

ago

[tbill]

yes, for the door lock, the polarity is just switched. i think the bcm is on the drivers side under the dash to the left of the steering column [i think].

i'll bring up the diagram again if i remember tomorrow while at work, and also confirm bcm location.

[ago]

tbill,

No worries, I have located the BCM. I'm still wondering whether that's the culprit. I'm pretty sure now, but what do you think ?

Thanks for looking things up for me,

ago

[tbill]

i printed out the schematics for it all today, but i neglected to bring them home , but, from looking at them, and thinking about the issues you're having [obviously if the car was at hand, with test equipt. and diagrams in hand it'd be easier], i'm leaning towards a BCM. i'd hate to have you fork over the cash for a new BCM just on my on-line observations/opinion though.


what i want to do is scan the schematics, and throw them up on a web page so you can see them, then maybe we can 'walk thru' a few tests via I/M or something, what do you think? all you'll need is a test light or volt meter, and a few thousand steps between the car and your PC

lemme know what you think,

tbill

[ago]

tbill,

I have my ham radio (amateur radio) license, and I'm very comfortable with electronics, voltmeters, etc...

No problem on troubleshooting with your guidance. Let's do it.

Thanks again,

ago

[tbill]

ok, sounds good, i'll get it all scanned and on a page by the weekend, look for a page link in this thread by friday night.

tbill

[tbill]

ok, i think we can skip the schematic and i can tell you what circuit in which connector to check. at the bcm, you should be able to 'back probe' the terminal with your meter.

first test, back probe terminal A3 [wire should be white in color]in bcm connector C1 [purple in color, 16 cavities], other lead to ground, press unlock switch on door, should get battery voltage [this is unlock input to bcm from door lock switches]. if this isn't battery voltage or near it, you have a wire issue.

if ok, the next wire to back probe will be in the same connector, but terminal A6 [wire should be tan in color], press either door unlock switch, or remote unlock switch, voltage should be battery or near it, if ok, it's a wire issue, if not ok, bcm is faulty. [this is 'unlock' voltage to the drivers door power door lock actuator]

trunk release, back probe same bcm connector at terminal A5 [black/white wire], press trunk release, should have battery voltage or near it [bcm sends batt. V directly down this circuit to trunk solenoid], if no voltage, bcm is faulty, if ok, wire issue between bcm and release solenoid.

i think this should get you situated. i should be around tomorrow, so i'll check in every now and again to see how you make out, hope this helps,

tbill

[ldickson55]

Originally Posted by tbill

if they were located in a 'high moisture' area [venture/montana/silhouete[sp?] vans have water leak issues, and the wire harness under the carpet gets wet and splices corrode, usually affecting door lock operation].

tbill

Just wanted to pass on a huge thank you. My wife came home today and said "the van's possessed - the door locks keep going off randomly"

Your post pointed me in the right direction, and 15 mins later the problem was solved. You made my day (and problably saved me a couple tracking down the problem.)

Thanks again.