Doors won't lock/unlock with fob or door switches ***FIXED!***
05-17-2024, 07:33 AM
#1
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Doors won't lock/unlock with fob or door switches ***FIXED!*** 2000 Trans Am
My keyfobs (I have 3) will turn factory alarm on & off, but will not lock or unlock the doors. The "panic" horn alarm and hatch release buttons still do what they are supposed to as well.
Also, the doors will not lock or unlock using either of the interior door switches/buttons.
I assumed it was just a fuse, but that doesn't seem to be the case. Unless I'm somehow not finding it.
I think, but am not 100% sure that this started happening soon after my Holley Terminator X Max conversion. It is mounted in glovebox and obviously, the related wiring is there and routed next to old factory engine harness.
I do still have the factory ECU as well, which still operates gauges, fuel pumps, etc.
No idea where to start diagnostics, so any ideas or insight is definitely appreciated.
My keyfobs (I have 3) will turn factory alarm on & off, but will not lock or unlock the doors. The "panic" horn alarm and hatch release buttons still do what they are supposed to as well.
Also, the doors will not lock or unlock using either of the interior door switches/buttons.
I assumed it was just a fuse, but that doesn't seem to be the case. Unless I'm somehow not finding it.
I think, but am not 100% sure that this started happening soon after my Holley Terminator X Max conversion. It is mounted in glovebox and obviously, the related wiring is there and routed next to old factory engine harness.
I do still have the factory ECU as well, which still operates gauges, fuel pumps, etc.
No idea where to start diagnostics, so any ideas or insight is definitely appreciated.
Last edited by rel3rd; 05-17-2024 at 10:21 PM. Reason: Fixed
05-17-2024, 04:48 PM
#2
The door locks are controlled by the BCM. The door switches are grounding switches which provide a ground signal to an unlock input and a lock input at the BCM. The remotes simply send a signal to the BCM in place of the door switch ground signals.
Since the locks don't work with the remotes, it's probably safe to assume that the door switches are not the problem. Fortunately, troubleshooting at the BCM is fairly straight forward other than being awkward to access. All of the door lock wires are in the green 6-pin connector at the BCM. Unplug it and use a jumper wire and a test light to provide power and ground to various combinations of the pins (use the jumper wire for ground and the test light for power - the lamp in the test light will prevent an accidental short to ground).
Connect tan wire to ground then touch the probe of the powered test light to the gray wire - all door should lock.
Connect gray wire to ground the touch test light probe to tan - driver's door should unlock.
Leave gray wire connected to ground then touch test light probe to black - passenger's door should unlock.
If you don't get these results then the problem is either the lock mechanism in the door(s) or the wiring from the BCM to the locks. If these tests work properly (as I expect will be the case) then the BCM is the problem.
Since the locks don't work with the remotes, it's probably safe to assume that the door switches are not the problem. Fortunately, troubleshooting at the BCM is fairly straight forward other than being awkward to access. All of the door lock wires are in the green 6-pin connector at the BCM. Unplug it and use a jumper wire and a test light to provide power and ground to various combinations of the pins (use the jumper wire for ground and the test light for power - the lamp in the test light will prevent an accidental short to ground).
Connect tan wire to ground then touch the probe of the powered test light to the gray wire - all door should lock.
Connect gray wire to ground the touch test light probe to tan - driver's door should unlock.
Leave gray wire connected to ground then touch test light probe to black - passenger's door should unlock.
If you don't get these results then the problem is either the lock mechanism in the door(s) or the wiring from the BCM to the locks. If these tests work properly (as I expect will be the case) then the BCM is the problem.
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rel3rd (05-17-2024)
05-17-2024, 05:04 PM
#3
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iTrader: (43)
The door locks are controlled by the BCM. The door switches are grounding switches which provide a ground signal to an unlock input and a lock input at the BCM. The remotes simply send a signal to the BCM in place of the door switch ground signals.
Since the locks don't work with the remotes, it's probably safe to assume that the door switches are not the problem. Fortunately, troubleshooting at the BCM is fairly straight forward other than being awkward to access. All of the door lock wires are in the green 6-pin connector at the BCM. Unplug it and use a jumper wire and a test light to provide power and ground to various combinations of the pins (use the jumper wire for ground and the test light for power - the lamp in the test light will prevent an accidental short to ground).
Connect tan wire to ground then touch the probe of the powered test light to the gray wire - all door should lock.
Connect gray wire to ground the touch test light probe to tan - driver's door should unlock.
Leave gray wire connected to ground then touch test light probe to black - passenger's door should unlock.
If you don't get these results then the problem is either the lock mechanism in the door(s) or the wiring from the BCM to the locks. If these tests work properly (as I expect will be the case) then the BCM is the problem.
Since the locks don't work with the remotes, it's probably safe to assume that the door switches are not the problem. Fortunately, troubleshooting at the BCM is fairly straight forward other than being awkward to access. All of the door lock wires are in the green 6-pin connector at the BCM. Unplug it and use a jumper wire and a test light to provide power and ground to various combinations of the pins (use the jumper wire for ground and the test light for power - the lamp in the test light will prevent an accidental short to ground).
Connect tan wire to ground then touch the probe of the powered test light to the gray wire - all door should lock.
Connect gray wire to ground the touch test light probe to tan - driver's door should unlock.
Leave gray wire connected to ground then touch test light probe to black - passenger's door should unlock.
If you don't get these results then the problem is either the lock mechanism in the door(s) or the wiring from the BCM to the locks. If these tests work properly (as I expect will be the case) then the BCM is the problem.
Unfortunately, rain is coming the next few days, but I will report back ASAP.
05-17-2024, 10:19 PM
#5
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Thread Starter
iTrader: (43)
This got me thinking...especially after realizing where the BCM is.
I put the Holley setup in the car over a year ago, and remembered (once you jarred my memory), that while running wiring harnesses under the carpet, into the glovebox, and through the firewall, I came upon some sort of shoddy installed aftermarket alarm system wiring spliced into the BCM wiring.
I cut all of that spliced and T tapped wiring out, and evidently, I inadvertently cut the 2 door lock wires by accident....went out this evening and found that issue, reconnected and back in business.
Thanks again!
I put the Holley setup in the car over a year ago, and remembered (once you jarred my memory), that while running wiring harnesses under the carpet, into the glovebox, and through the firewall, I came upon some sort of shoddy installed aftermarket alarm system wiring spliced into the BCM wiring.
I cut all of that spliced and T tapped wiring out, and evidently, I inadvertently cut the 2 door lock wires by accident....went out this evening and found that issue, reconnected and back in business.
Thanks again!
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wannafbody (05-18-2024)
05-19-2024, 02:13 PM
#6
You're welcome. I'm glad it turned out to be an easy fix.
I've always accessed the BCM the traditional way - dropping the glove box out of the way. Is it easier to access through the radio opening? That would be helpful since removing the radio only takes a minute or two.
I've always accessed the BCM the traditional way - dropping the glove box out of the way. Is it easier to access through the radio opening? That would be helpful since removing the radio only takes a minute or two.
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rel3rd (05-19-2024)