Security system discharging battery

[roadrunner]

Did some searching on the site and did not find this problem referenced. When I lock up my truck with the key fob the security light stays on unless I stand there and watch for a few seconds to see if the security light goes off and hit the lock button again if it does not. When this happens (light staying on if I don't notice it) it slowly runs the battery down. If I do the re-lock fob and watch the light will go out and no battery discharge. Had me fooled for a long time thinking something else was draining battery or battery was going bad. This only happens when I am leaving the truck sit for a month or two without driving it. Lately I have also noticed the range of the fob is greatly reduced. Used to work from 30+ feet away now need to be right by the door to lock and unlock and yes I have put new battery in the fob. I'm thinking perhaps the BCM is going bad? Anybody with any other ideas?

[HenryJ]

The receiver module is above the left kick panel. Check our mod page for the extended range mod.

[roadrunner]

The receiver module is above the left kick panel. Check our mod page for the extended range mod.

I think ya kinda missed the main point of the post. The security light will stay on and drain the battery unless I do a second lock with the key fob. I'm more concerned about that than the range of the fob. Also as stated the fob range has decreased which leads me to suspect the BCM.

[HenryJ]

You don't suspect a faulty receiver module? How about unplugging it and see if the problem persists?

[roadrunner]

You don't suspect a faulty receiver module? How about unplugging it and see if the problem persists?

I'll try unplugging but have little to no expectation of improvement. I don't suspect the receiver as it still is functional even if the range is reduced. This is why I was leaning more towards the bcm. The logic being if the receiver is sending signal to the bcm to lock the doors which it clearly is then I suspect the bcm as it is failing to complete the cycle and turn off the security dash light and then slowly draining the battery. Your thoughts??

[ApproachMedium]

When you press the lock button if the light stays on, does the doors respond with a lock? I wonder if you have a bad lock module not reporting to the computer that its actually locked. I had this problem with my Volkswagen, it turned out to be a cold solder joint in the latch module itself. My friends blazer had a similar issue with things staying lit in the cluster after shutting the truck off which was bad/cold solder points in the gauge cluster which is a very common problem with GM products with digital gauge clusters.

[roadrunner]

When you press the lock button if the light stays on, does the doors respond with a lock? I wonder if you have a bad lock module not reporting to the computer that its actually locked. I had this problem with my Volkswagen, it turned out to be a cold solder joint in the latch module itself. My friends blazer had a similar issue with things staying lit in the cluster after shutting the truck off which was bad/cold solder points in the gauge cluster which is a very common problem with GM products with digital gauge clusters.

Yes, all 4 doors lock and can't be opened with the outside handles. The way I get bounced around on the mail route with the truck that solder joint sounds like a possibility at the lock modules as I have verified the doors are all locked manually from inside as well before using the fob. The light will always go out after a 2-3 second delay on the second locking with the key fob. Not ruling out the cluster but put it low on the suspect list as it lights and goes out as long as fob is used twice with a pause in between. A quick second lock with fob honks the horn but the light stays on requiring a 5-10 second delay before attempting to re-lock. After re-lock and a 2-3 second delay the light then goes off and the battery does not run down. Thanks for the input. Gives me more directions to look into.