Trunk Sensor won't stop beeping

I need help.
I have a '98 Grand Prix GTP.
I took it to the dealer because the trunk indicator keeps flashing that the trunk is open.
The dealer charged me for a new latch.
That didn't fix it.

Is there a way to disable the trunk sensor or the sound on the sensor?
Thanks

It sounds like they didn't adjust the latch properly.

Not unless you want to do some wiring mods from the body control module (BCM) to the Instrument Panel. The trunk ajar switch is also used for the theft deterrent system. In a worse case scenario you may a bad body control module and it is not sensing the trunk is closed. The trunk ajar switch sends a ground to the BCM. The BCM is also giving you the chime warning.

Is the trunk courtesy light working? Is it staying on or turning off when the trunk is closed? The trunk ajar switch and trunk light switches are the same.

If you look carefully on the rear trunk latching mechanism (center) you will see a black lever which is part of the trunk ajar switch. You can manually control this to test and troubleshoot. Try moving it up and down and observe the trunk light.

Let us know what you find and we can go from there.

The latch was replaced by the dealer as his solution.
That obviously didn't work.

I tried the black lever in the back trunk, its still sensing that the trunk is open.

Its not the issue of the sensor responding that the trunk is open and flashing the trunk light on the dash.

But its the open/closed/open/close beeping. It goes of every 5 seconds.

My dealer couldn't seem to trouble shoot the reason for the sensor. Is there a way to turn off the sound?

Thanks

The latch was replaced by the dealer as his solution.
That obviously didn't work.

I tried the black lever in the back trunk, its still sensing that the trunk is open.

Its not the issue of the sensor responding that the trunk is open and flashing the trunk light on the dash.

But its the open/closed/open/close beeping. It goes of every 5 seconds.

My dealer couldn't seem to trouble shoot the reason for the sensor. Is there a way to turn off the sound?

Thanks


It still sounds like the BCM is not getting the signal from the sensor.

On the dealer if it involves detailed troubleshooting like reading wiring diagrams and using a mulitimeter they are normally lost. The Tech II they use probably did not reveal anything.

If it's not a wiring issue, and the BCM is bad, there are 3 different ones, depending on if you have keyless entry and/or factory security. If you need one, let me know, as i can sell you one for much less than a dealer. You can check your SPID label on the underside of the trunk lid for the option codes listed below, or give me the last 8-digits of your vin and I can tell you which you need.
with both factory keyless entry(UAO) and security(UA6)
-10439803= $90.88 + s/h
with keyless entry (UAO) only
-10427831= $48.53 + s/h
w/o keyless entry or security (neither option code on SPID label)
-10427830= $92.24 + s/h
If you're interested, PM me with your zip code and I can get you an exact shipping quote so let me know. Hopefully it's just a wiring issue, but I figured I'd mention the above pricing so you don't get gouged at the dealer for the BCM.

If it's not a wiring issue, and the BCM is bad, there are 3 different ones, depending on if you have keyless entry and/or factory security. If you need one, let me know, as i can sell you one for much less than a dealer. You can check your SPID label on the underside of the trunk lid for the option codes listed below, or give me the last 8-digits of your vin and I can tell you which you need.
with both factory keyless entry(UAO) and security(UA6)
-10439803= $90.88 + s/h
with keyless entry (UAO) only
-10427831= $48.53 + s/h
w/o keyless entry or security (neither option code on SPID label)
-10427830= $92.24 + s/h
If you're interested, PM me with your zip code and I can get you an exact shipping quote so let me know. Hopefully it's just a wiring issue, but I figured I'd mention the above pricing so you don't get gouged at the dealer for the BCM.

Strange that a BCM without keyless entry or security is more than it is with it.

The fun won't be over if he has to replace the BCM. It must be programmed by the dealer with a Tech II machine. More dinero $$$.

I'd make darn sure the BCM is bad by properly troubleshooting the circuit with a GM wiring diagram and multimeter. Very easy to determine whether it is the BCM, wiring or any sensor.

BTW - I have never encountered a GTP that did not have theft-deterrent/Passkey and a Level 4 or Class 4 BCM.

Actually Bob, I had someone on here give me a vin on a 98 GTP to check for him, and it didn't have keyless entry or anti-theft, but it had leather, heads up, power heated seat, etc...loaded. Shocked me too, I thought GTP's were all equipped with keyless and security.

Actually Bob, I had someone on here give me a vin on a 98 GTP to check for him, and it didn't have keyless entry or anti-theft, but it had leather, heads up, power heated seat, etc...loaded. Shocked me too, I thought GTP's were all equipped with keyless and security.

I don't doubt you Rich or that it is not possible. All I said was "I" never encountered a GTP without RKE and anti-theft. We've got over 25 Grand Prixs in the local club and 8 are '97 and up GTPs. All have RKE and a level 4 BCM. I spent enough time helping the guys set up sensitivity for the past 5 years along with a bunch of tech help.

I wonder if the original poster who has a GTP has remote keyless and anti-theft???

My GTP does indeed have remote keyless. I believe it has a passive alarm. I seem to remember (or it may have been a past vehicle), I entered into the vehicle which I unlocked from the outside thru an opened window which triggered the alarm. Putting the key in the ignition I believe was the solution.

Is there a way to disable the black lever in the trunk?
Or should I say is there a way to wire it that gives the BCM a constant positive signal?

Thanks

My GTP does indeed have remote keyless. I believe it has a passive alarm. I seem to remember (or it may have been a past vehicle), I entered into the vehicle which I unlocked from the outside thru an opened window which triggered the alarm. Putting the key in the ignition I believe was the solution.

Is there a way to disable the black lever in the trunk?
Or should I say is there a way to wire it that gives the BCM a constant positive signal?

Thanks

I figured you did. Like I said earlier I've never seen a GTP one without one. :biggrin:

Maybe. I'll check the the GM wiring daigrams and see what the possibilities are. A fix will only work if the BCM does not have an internal malfunction.

Is there a way to disable the black lever in the trunk?
Or should I say is there a way to wire it that gives the BCM a constant positive signal?

Thanks

The trunk lid switch sends a ground when the trunk is ajar to the BCM. It doesn't appear to be a positive level voltage. However, to keep the circuit inhibited it must have no input signal or an open.

Try unplugging the switch and see what it does. There should be two connectors on the trunk latch assembly. The smaller of the two is for the switch. The other is for the trunk release solenoid.

The ground or no signal (open) inputs the BCM at connector C2 pin D13. It should be a red black wire. Some GPs may have different wire color coding but the connectors and pins are correct.

At the trunk switch connector the output is pin A (red/black wire). Pin B of the switch is a constant ground.

There doesn't appear to be any other connection points and it is a straight shot from the switch connector to the BCM connector.

Good luck!