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Discussion Starter · #1 ·
I’ve read a couple of other post with some similarities to issues I’m having, but some had no responses either. 2008 2500 crew cab w/ 165k miles.

Two nights ago we came out of a restaurant after a very heavy rain. Key fob would not unlock the truck. Opened it the key and set off the alarm. Put the key in ignition and turned it on to disable alarm, but it did not. Tried to start the truck, but would not even attempt to crank. The PassLock indicator was solid display on the DIC. Took Uber home to get my other key, came back and after having it turned on for a few minutes all the gauges activated and it started up. There was a constant audible tone coming from under the dash that lasted for about a minute. Lots of weird cycles through service messages, but it cleared up by the time I drove home. I went through the steps to add both fobs to the system and everything was working fine.

Came out the next morning, same problem. Would not respond and alarm went off again using the key. This time I could not get it to recover or attempt to even crank. PassLock again was solid display, not flashing. Tried again this afternoon and key fob unlocked the truck after doing nothing to it. Started up no problems. I shut it off and decided not to use the FOB to lock it. I used the electric door lock and the PassLock indicator started flashing rapidly on the dash and there were three chimes. The driver door was open. I unlocked it and locked all the door manually for the night.

WTF is going on? Someone had the idea maybe moisture from all the rain this week could be causing a problem. I’m skeptical of that, but can’t rule it out given how it just started working again after it had stopped raining for a bit. Is my BCM going bad, ignition lock issue, some PassLock component dying?
 

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I’ve read a couple of other post with some similarities to issues I’m having, but some had no responses either. 2008 2500 crew cab w/ 165k miles.

Two nights ago we came out of a restaurant after a very heavy rain. Key fob would not unlock the truck. Opened it the key and set off the alarm. Put the key in ignition and turned it on to disable alarm, but it did not. Tried to start the truck, but would not even attempt to crank. The PassLock indicator was solid display on the DIC. Took Uber home to get my other key, came back and after having it turned on for a few minutes all the gauges activated and it started up. There was a constant audible tone coming from under the dash that lasted for about a minute. Lots of weird cycles through service messages, but it cleared up by the time I drove home. I went through the steps to add both fobs to the system and everything was working fine.

Came out the next morning, same problem. Would not respond and alarm went off again using the key. This time I could not get it to recover or attempt to even crank. PassLock again was solid display, not flashing. Tried again this afternoon and key fob unlocked the truck after doing nothing to it. Started up no problems. I shut it off and decided not to use the FOB to lock it. I used the electric door lock and the PassLock indicator started flashing rapidly on the dash and there were three chimes. The driver door was open. I unlocked it and locked all the door manually for the night.

WTF is going on? Someone had the idea maybe moisture from all the rain this week could be causing a problem. I’m skeptical of that, but can’t rule it out given how it just started working again after it had stopped raining for a bit. Is my BCM going bad, ignition lock issue, some PassLock component dying?
There was a bulletin from GM about an issue like this. Water can enter the cab from the third brake light assy on top of the cab. It can then travel down the body channel and get water on the Remote Control module that is located in the aft driver side close out panel. It is towards the bottom of the cab. This normally causes numerous problems including remotes not working, security system issues and TPMS problems. Dean
 

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Discussion Starter · #3 ·
There was a bulletin from GM about an issue like this. Water can enter the cab from the third brake light assy on top of the cab. It can then travel down the body channel and get water on the Remote Control module that is located in the aft driver side close out panel. It is towards the bottom of the cab. This normally causes numerous problems including remotes not working, security system issues and TPMS problems. Dean
If anyone knows what TSB # it is or has a link, please reply with it. Thanks!
 

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Discussion Starter · #6 ·
Thank you! Will check out the receiver to see if it’s corroded and if I have a leaking third brake light seal, at least to start with.
 

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Discussion Starter · #7 ·
I went out to my truck and noticed I have big water stains in both back corners of my headliner. My third taillight also has some cracks in it and not sure there is a seal underneath it. The truck was repainted prior to me buying it so the genius who did the job may not have put a seal back in.
 

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I went out to my truck and noticed I have big water stains in both back corners of my headliner. My third taillight also has some cracks in it and not sure there is a seal underneath it. The truck was repainted prior to me buying it so the genius who did the job may not have put a seal back in.
Like the video shows, the remote sensor module looked fine, you have to open it up to see any water intrusion/damage. I chased this down when my LMM was having GMLAN serial bus issues. Mine was fine but I did see a bit of a crack in the seal on the cab brake light. A small dab of clear RTV took care of that. It sound like this might be your issue. Good Luck, Dean
 

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Discussion Starter · #9 ·
Pretty sure this is the problem! Corrosion on the components that are at the bottom of the module as it is mounted in the vehicle, meaning water was pooling in there and shorting it out. The updated part number is 20803735 and cost about $70 from GM parts warehouses.

1090073


1090074
 
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