2000 Cavalier Z24 remote door lock problem

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

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?

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

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].

ok, i did some checking today, there isn't a drivers door unlock relay like i thought :mad: 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.

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

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

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

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.

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

i printed out the schematics for it all today, but i neglected to bring them home :confused: , 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 :smile:

lemme know what you think,

tbill

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

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

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

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.

haha, glad i helped out, in a round about way :smile:

tbill,

I've been super busy in the last few days. I'll do these tests in the next couple of days or so, and report back here.

You are great. Thanks for the info...

more later...

ago

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

Hi again tbill,

Sorry about not getting back to you sooner. I've been so busy.

Anyways I did the above diagnostics, and it turns out that the BCM is the culprit.

Thanks for your detailed info.

Now the search for a good deal on a replacement BCM.

Any ideas ??

Thanks so much,

ago

Hi tbill,

Now that I have a new BCM (actually a used one from a used parts dealer), I need to find out how to program it for my car.

When I install it (disconnect 12V at fuse box first to avoid power spikes), I cannot start the car (fuel gets shut off) and the radio showes "Locked" on the radio display.

My car has the Passlock key theft deterrent system, where if a non-authorised or other car key inserted, the fuel is cut-off and the car will not start.

I tried to "relearn" the key with the new BCM installed, by turning the key to the "ON" position (not "START") and leaving it ON for 10 minutes. The security icon flashes for awhile, then goes steady, then goes out. Then I turn off the key for 10 seconds then turn over to start and still no luck in starting the engine. Tried this 2 or 3 times (10 minute wait while in "ON", then 10 sec. "OFF" then "START"). No luck.

I also tried to resynchronise the remote, by pressing and holding "LOCK" and "UNLOCK" for several seconds. The response should be a unlock/lock cycling of the door locks. No luck there too.

Re-installing the original (but faulty) BCM allows me once again to start the engine, get my previous partial door locking condition, and also clears the "LOCKED" car radio that I got with the new BCM.

I am not 100% sure of my programming steps. What am I doing wrong ?

Thanks,

ago

hi, to be honest, it's been awhile since i put a bcm in one of those. i'll have to look up the procedure in our service info on how to program it monday. i honestly can't remember if it is a plug and play with a key relearn, or if it is an actual 'scanner/PC re-program'. i'll post what i find for you monday evening when i get home from work.

Hi tbill,

Thanks for the quick reply. It may require a "Tech II", or just a scan for codes first, but I also heard that it just requires a key relearn (3 times the 10 minute ON, and on the last cycle go straight afterwards to start". Then resync the key remotes...standing by for your info on Monday.

Thanks again bigtime !

ago

hey, looked it up today, and it does need to be programmed with a tech 2, then most likely it will need the key fobs programmed and the theft deterrent [pass lock] will need to be learned as well.

hope this helps,

tbill

I just wanted to say I am having the exact same problem with my 2000 Cavalier Z24 remote. Could you please tell me what was the solution?

I have a 2000 Sunfire, the Drivers door will not lock with the key, the manual lock button, the automatic lock button, or the keyless entry fob. I had the door apart, and I have good power goin to the unit. The door linckages all seem fine but still won't lock. seems like it is seized. My question is, how do I fix this?, could I just take out the electric lock module ( this is where i think the problem is, or is there an easier solution?

Thanks
Geo

geo, sounds like the door latch itself is seized. might get it working again if you spray the daylights out of it repeatedly with penetrating oil.

geo, sounds like the door latch itself is seized. might get it working again if you spray the daylights out of it repeatedly with penetrating oil.

Thanks, I guess that's what I'll have to try until I get the time to tear the door down and get a good look at what is going on in there(or not going on).

Thanks
Geo.

tbill,

Hi again. Finally brought the car to the dealer (for Tech 2 reprogram). Turns out it was just the "RFA" fuse. The BCM wasn't at fault all along. $30 later for a fuse change (I felt so silly), I was on my way. I should have checked all the fuses in the fuse panel on the left side.

Now I have a spare BCM to sell...oh well...

Thanks again,

ago

tbill,

Hi again. Finally brought the car to the dealer (for Tech 2 reprogram). Turns out it was just the "RFA" fuse. The BCM wasn't at fault all along. $30 later for a fuse change (I felt so silly), I was on my way. I should have checked all the fuses in the fuse panel on the left side.

Now I have a spare BCM to sell...oh well...

Thanks again,

ago
Thank you so much Ago for telling how you resolved the problem. I really appreciate you helping others such as myself. Thank you again.

Wow I just went down and check that fuse after reading this thread>>>>>>and bam everything works now. Cheers