1998 Trunk Issues
Thread Starter
Cruising
Joined: Jul 2016
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1998 Trunk Issues
Just recently bought a 1998 C5 Vette. Trunk is popping open after we close and lock everything up. Some times its within 20 minutes, other times it takes as long as an hr. Any one know if heavy vibrations on the road can cause this? Could something be wrong with the latching mechanism inside that it is not catching and when a semi-drives by the vibration helps to kick the trunk open? Has not happened when driving yet, but has happened when parked multiple times. If it is the latching mechanism is there a way to adjust it or do we need to buy a new one all together?
Any help you can provide would be greatly appreciated.
Thank you
Any help you can provide would be greatly appreciated.
Thank you
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
Vert? FRC? Targa Top? I don't know how much IF any difference it makes but it's good to know anyway what you have... the more info the better. Some things (electrical) changed from year to year sometimes...
Read thru this and see if anything is applicable...
https://www.corvetteforum.com/forums...ng-open-2.html
Read thru this and see if anything is applicable...
https://www.corvetteforum.com/forums...ng-open-2.html
Last edited by 73Corvette; Jul 16, 2016 at 08:06 PM.
Thread Starter
Cruising
Joined: Jul 2016
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Thank you for getting back so quickly. I have a targa top. I read the thread you provided, I actually didn't check the passenger side door to see if it unlocked too, I will have to check that in the morning. Also I am very new to the Vette community and stuff, the thread mentions cleaning the BCM, what is a BCM and where is it located?
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,441
Likes: 2,186
From: Buffalo Texas
Thank you for getting back so quickly. I have a targa top. I read the thread you provided, I actually didn't check the passenger side door to see if it unlocked too, I will have to check that in the morning. Also I am very new to the Vette community and stuff, the thread mentions cleaning the BCM, what is a BCM and where is it located?
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
The BCM is the Body Control Module it is the Central Nervous System of your cars functions.. seats, stereo, doors, lights, that kind of stuff... The PCM - Power Control Module is the Nerve Center for the engine, trans, steering...
So, the BCM is like Mr Pounder said the footwell on the passenger side hiding behind a James Bond type panel to conceal it...
MANY electrical issues in the C5 are caused by LOW BATTERY VOLTAGE... should be at least 12.6 volts at the battery.
Your C5 is VERY smart and can tell you when something is wrong most of the time... but, you have to PULL the CODES to find out what it could be... somethings it doesn't tell...then you have to go by experience and knowledge to make a diagnosis.
Here is how you pull the codes... write them down and post them...
So, the BCM is like Mr Pounder said the footwell on the passenger side hiding behind a James Bond type panel to conceal it...
MANY electrical issues in the C5 are caused by LOW BATTERY VOLTAGE... should be at least 12.6 volts at the battery.
Your C5 is VERY smart and can tell you when something is wrong most of the time... but, you have to PULL the CODES to find out what it could be... somethings it doesn't tell...then you have to go by experience and knowledge to make a diagnosis.
Here is how you pull the codes... write them down and post them...
Thread Starter
Cruising
Joined: Jul 2016
Posts: 10
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I have the owners manual. Car is currently at my parents house cause I didn't trust it in my driveway/neighborhood if the trunk is going open up again overnight so I cant look into this until tomorrow morning. but I think it is super helpful. I am so thankful for these forums. My dad is super handy at these kinds of car issues, so even if I don't understand fully he will probably have an idea or know what you all are talking about. I have a 1998 Corvette Coupe, with a targa top. Not quite sure what else you need to know. The previous owners didn't have the FOBs for the car and we ordered two from one of the corvette magazines, could the FOBs be the issue too? We got the FOBs because the locking button/switch on the drivers door doesn't work but everything else does, like the windows, memory settings, mirror settings, and even the unlock button works, but not the lock. The passenger side works fine tho.
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Thread Starter
Cruising
Joined: Jul 2016
Posts: 10
Likes: 0
BCM/Trunk Issue
Thank you for this, I will certainly look at this tomorrow with my dad!!!
The BCM is the Body Control Module it is the Central Nervous System of your cars functions.. seats, stereo, doors, lights, that kind of stuff... The PCM - Power Control Module is the Nerve Center for the engine, trans, steering...
So, the BCM is like Mr Pounder said the footwell on the passenger side hiding behind a James Bond type panel to conceal it...
MANY electrical issues in the C5 are caused by LOW BATTERY VOLTAGE... should be at least 12.6 volts at the battery.
Your C5 is VERY smart and can tell you when something is wrong most of the time... but, you have to PULL the CODES to find out what it could be... somethings it doesn't tell...then you have to go by experience and knowledge to make a diagnosis.
Here is how you pull the codes... write them down and post them...
https://www.youtube.com/watch?v=SviRjIsy9G4
So, the BCM is like Mr Pounder said the footwell on the passenger side hiding behind a James Bond type panel to conceal it...
MANY electrical issues in the C5 are caused by LOW BATTERY VOLTAGE... should be at least 12.6 volts at the battery.
Your C5 is VERY smart and can tell you when something is wrong most of the time... but, you have to PULL the CODES to find out what it could be... somethings it doesn't tell...then you have to go by experience and knowledge to make a diagnosis.
Here is how you pull the codes... write them down and post them...
https://www.youtube.com/watch?v=SviRjIsy9G4
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,441
Likes: 2,186
From: Buffalo Texas
I have the owners manual. Car is currently at my parents house cause I didn't trust it in my driveway/neighborhood if the trunk is going open up again overnight so I cant look into this until tomorrow morning. but I think it is super helpful. I am so thankful for these forums. My dad is super handy at these kinds of car issues, so even if I don't understand fully he will probably have an idea or know what you all are talking about. I have a 1998 Corvette Coupe, with a targa top. Not quite sure what else you need to know. The previous owners didn't have the FOBs for the car and we ordered two from one of the corvette magazines, could the FOBs be the issue too? We got the FOBs because the locking button/switch on the drivers door doesn't work but everything else does, like the windows, memory settings, mirror settings, and even the unlock button works, but not the lock. The passenger side works fine tho.
Last edited by Pounder; Jul 16, 2016 at 10:19 PM.
Thread Starter
Cruising
Joined: Jul 2016
Posts: 10
Likes: 0
So we removed the batteries from the FOBs and the trunk still pops open - so we ruled this out. We removed the BCM and cleaned it (although it was fairly clean to begin with). The trunk still pops open. we cleared the following codes:
P1431 - FUEL LEVEL SENSOR PERFORMANCE
B0521 - TACHOMETER SIGNAL CIRCUIT MALFUNCTION
B2252 - KEY CYLINDER SWITCH CIRCUIT
B2253 - KEY CYLINDER SWITCH CIRCUIT
B2282 - BATTERY #1 CIRCUIT
B2283 - BATTERY #1 CIRCUIT
B2284 - BATTERY #2 CIRCUIT
B2285 - BATTERY #2 CIRCUIT
B2205 - RIGHT WINDOW DOWN SWITCH CIRCUIT
B2265 - VERTICAL POSITION SENSOR CIRCUIT
B2177 - SEAT FRONT DOWN SWITCH SHORTED TO GROUND
B2197 - SEAT REVERSE SWTICH SHORTED TO GROUND
B2600 - SEAT MOTOR TO BATTERY VOLTAGE
B0851 - BATTERY #1 OUT OF RANGE
B0856 - +5 VOLTAGE REFERENCE OUT OF RANGE
We cleared all of these and waited, and 30 minutes later the trunk popped again and the following codes appeared
B0507 - LH DRL RELAY CIRCUIT
B2587 - COLUMN LOCK/UNLOCK DRIVE A
B2592 - COLUMN LOCK/UNLOCK DRIVE B
B2252 - KEY CYLINDER SWITCH CIRCUIT
We cleared these and are charging the battery and while charging the battery the trunk popped again.
Any ideas what could be causing it. I've tried all your suggestions so far. Let me know, I have all day to work on this if you have any other suggestions. Thanks again.
P1431 - FUEL LEVEL SENSOR PERFORMANCE
B0521 - TACHOMETER SIGNAL CIRCUIT MALFUNCTION
B2252 - KEY CYLINDER SWITCH CIRCUIT
B2253 - KEY CYLINDER SWITCH CIRCUIT
B2282 - BATTERY #1 CIRCUIT
B2283 - BATTERY #1 CIRCUIT
B2284 - BATTERY #2 CIRCUIT
B2285 - BATTERY #2 CIRCUIT
B2205 - RIGHT WINDOW DOWN SWITCH CIRCUIT
B2265 - VERTICAL POSITION SENSOR CIRCUIT
B2177 - SEAT FRONT DOWN SWITCH SHORTED TO GROUND
B2197 - SEAT REVERSE SWTICH SHORTED TO GROUND
B2600 - SEAT MOTOR TO BATTERY VOLTAGE
B0851 - BATTERY #1 OUT OF RANGE
B0856 - +5 VOLTAGE REFERENCE OUT OF RANGE
We cleared all of these and waited, and 30 minutes later the trunk popped again and the following codes appeared
B0507 - LH DRL RELAY CIRCUIT
B2587 - COLUMN LOCK/UNLOCK DRIVE A
B2592 - COLUMN LOCK/UNLOCK DRIVE B
B2252 - KEY CYLINDER SWITCH CIRCUIT
We cleared these and are charging the battery and while charging the battery the trunk popped again.
Any ideas what could be causing it. I've tried all your suggestions so far. Let me know, I have all day to work on this if you have any other suggestions. Thanks again.
Thread Starter
Cruising
Joined: Jul 2016
Posts: 10
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FOBS/Trunk Issues
So I ruled out the FOBs because I removed the batteries from both FOBs and the trunk still popped open. The car does have memory seats included. Not sure what else it could be. Trying everything, BCM, FOBs, Clearing Codes.
it could very well be the FOB's or the receiver, I know just the other day I hit the wrong button and after closing the door the hatch opened ????? that is also why I mentioned the owners manual, you can have different options as far as what the FOB's do ???? But that also depends on what options the car has like memory seats and such.
"My Dad's a TV Repairman"
Joined: Jul 2014
Posts: 471
Likes: 153
From: San Diego
As simple as it sounds, I had a similar issue with my old 2001, and it turned out to be the hatch button on the dash, shorting out against itself... Changed the button assembly with a used housing / button set from fleaBay and problem solved...
Last edited by Fed Up; Jul 17, 2016 at 12:15 PM.
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,441
Likes: 2,186
From: Buffalo Texas
I was just going to suggest the same or the wire grounding somewhere to the hatch solenoid !!
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
Interesting how the BCM is involved in operating the relay that releases the hatch whether one presses the button on the dash or uses a signal received from the FOB requesting the hatch be released....
That is why I suggested checking whether the BCM had ever been wet......... Corrosion inside the metal box that houses the BCM is not an uncommon C5 issue........
That is why I suggested checking whether the BCM had ever been wet......... Corrosion inside the metal box that houses the BCM is not an uncommon C5 issue........
and our "hunt" would turn into some extreme, danger filled, life threatening, wacko, OMG kinda of day...they were "interesting" 
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,441
Likes: 2,186
From: Buffalo Texas
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,441
Likes: 2,186
From: Buffalo Texas
That was another of my tongue in cheek "interesting" comments. I was well aware that the BCM controls FAR more things in these cars than most people realize/want to accept. Allows for great and varied functionality but can add a triple back flip with a double twist to problem diagnosis..... 
Especially to the old timers who are used to a switch directly operating what should be on the other end... 
Especially to the old timers who are used to a switch directly operating what should be on the other end... 
Thread Starter
Cruising
Joined: Jul 2016
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So like I said before, we removed the silver box (THE BCM) next to the fuse box. No oxidation (white spots) were found but we did clean it as suggested. The carpet is not wet nor are there any stains suggesting that it ever got wet previously. There is no evidence inside that panel that any water has gotten in that area. The only thing I can guess is the software to the BCM was compromised when we programmed the FOBs, because this issue happened after we programmed the FOBs. We have had the FOBS disconnected and batteries removed all day but the trunk still pops open, so I have ruled out that maybe the trunk release button on the FOB was causing it. We charged the battery and that did not help, we cleared out the codes under the diagnostics and that did not help. we removed the BCM and cleaned it. When we reinstalled the BCM within five minutes the trunk popped open again. This is leading me to believe that the programming of the FOBs has disrupted something in the software and is making this mechanism malfunction. Unless there is something else we haven't tried, but I have tried everything that has been suggested thus far. Does anyone know how much a new BCM costs?
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
That was another of my tongue in cheek "interesting" comments. I was well aware that the BCM controls FAR more things in these cars than most people realize/want to accept. Allows for great and varied functionality but can add a triple back flip with a double twist to problem diagnosis..... Especially to the old timers who are used to a switch directly operating what should be on the other end...
Especially to the old timers who are used to a switch directly operating what should be on the other end... ... Thanks Chuck for what you do... I am just a slow old timer, that's learning a lot from you.