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Keyless entry issue.

698 Views 15 Replies 2 Participants Last post by  cart7881
I had not driven my 2006 crew cab in a week or two. Key fob didn't work the next time i went to drive it. Got home and grabbed the spare to find it didn't work either. Cleaned the contacts and new batteries got them to pass the tester at OReilly. Now they work while the truck is running, but basically don't work after you power down the truck. No codes other than dimmer circuit (had that code for a long time) No other malfunctions. Truck is stock except radio, which was swapped 3plus years ago.
Any ideas?
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Does the horn blow when you push the red button on the remote? If this is an OEM remote it only has door lock/unlock and alarm functions. If the horns blows every time, it may be a door lock issue, not a key fob problem.

Try cleaning the ground points. There is a small black box, in the engine compartment, attached to the fender wall, next to the ABS module. Remove the one attach bolt and clean the surfaces. There is a second ground, exactly the same type box, located on the fender wall behind the air filter case. Could also be a problem with the driver's door lock switch logic board.

Keep us posted.
First off, the remotes are oem, not aftermarket. I believe they are original to the truck. I have an aftermarket key fob, but have not programmed it to the truck. I did not try the red button from inside the truck. It does dont work from outside the truck. The door locks all work from the driver's switch. I have not tried the passenger side. It's cold out and the shop is full, so only giving it a few minutes here and there. I will look at the grounds when I get a chance, Thanks for the reply.
Well, if the doors lock using the internal switch, there probably isn't a need to bother with the grounds. When the key fob is used the BCM locks/unlocks the doors with signals to the driver's door switch. What is most confusing is the symptom that the remote works with the engine running but doesn't when it is stopped. With the engine off, will the remote work if the key is in the on/run position? Looking for clues.
The key fob actually worked with the key off, until I opened the door and shut down the RAP. It almost acts like it is losing a power source. I Need to look at the circuits. I have a Haynes manual. It has redrawn diagrams, but sometimes they aren't terrible.
Just for the hell of it, with the engine off, hook up a jump start, battery charger or another battery and see if that changes anything. Also confirm whether or not the passenger door lock switch works (for all doors). It uses the same circuit as the BCM.
I pulled my truck in the shop Friday after work for a few minutes.
Door locks lock and unlock from both switches. Auto lock and unlock functions work as normal.
With key on and window open, key fob works but has very poor range. I could reach my arm out the open window and fob would work. You have to be right at the window for the fob to work. Again, this is with the key in run position. Turn off key and fob works until a door is opened.
Strange symptoms. Seem to point to an issue with the BCM. Maybe check the terminals in the connectors at the BCM for condition. Also check the antenna connection for the remote. It is a single wire plugged into the face of the BCM.

The control wires for the door locks are in the Black connector as are the door ajar switch inputs.

Note from the Service Manual (no explanation given): "Always remove the Black connector first and install the black connector first".

Did you try the suggestion in Post #6? You previously mentioned no problems while the engine was running. Wondering if it might be a power problem.
Update; I went out to get in the Colorado this morning to go to work. Got up by the driver's door before I thought to try the key fob, and to my surprise it unlocked the door. I made two stops on the way home. Seems to be back to normal. I have no idea why.
Hope it's permanent. Thanks for the update.
Update; I really haven't been driving this truck much because it needs a hub bearing replaced, and I haven't got it done yet, so driving the old S10 to work unless the weather is bad. I drove it one day last week due to slick roads. When I hit the unlock on the remote, it gave me the horn chirp like when you are trying to lock the doors with the key in the ignition. Tried it later while driving down the road and got the same response. Really hard to figure out what is going on, since you need the key on to read any data on the scanner. If you get it to lock with the remote, then it won't unlock with the fob and you have to use the key, it sets the alarm off (which it should, but annoying) .
Back in post #3 you left this sentence in regard to whether or not the horn sounded when you pushed the button on the remote: "It does dont work from outside the truck." Can you elaborate a bit on that? If the horn doesn't sound it could indicate that the BCM either isn't getting the signal from the remote or has an internal issue.

What did you find when you checked the condition of the connectors at the BCM? Was the remote antenna lead secure in the BCM?

If you know someone with a bi-directional scan tool, have them check to see if the BCM will actuate the door locks.
I got something out of the truck earlier today. Remote unlock worked, but horn chirped like it does when you hit the door lock button with the driver's door open. I have the locks on the no chirp on unlock, single chirp on lock mode.
I haven't pulled the trim off to check the bcm connections. It's been cold and I have only driven it 2 or 3 times
I have a SnapOn Solus edge scan tool, but i normally keep it at work.
I think we are finally getting past the bad weather, so I should be able to tinker with it more.
The problems with the remote seem to occur most often when the battery is the only source of power. How old is it and have you had it load tested?
The battery is probably 3-4 years old, but checked good around Thanksgiving. I have never had a problem startring it, even in below zero temps this winter.
Well, something strange is happening. So far you have had the remotes confirmed good. The switches for the door locks both operate normally and all door locks will lock and unlock.

What you have is a remote door lock system that seems to work with power turned on in the truck, but not with power off. As mentioned before, if you can get a scan tool to do a functional test of the locks it would indicate whether or not the circuit from the BCM to the door switch is good. Of course you would need the key on for that, but we only need to confirm that the circuit is good. If we know the BCM will lock/unlock the doors, when instructed, means the problem is with the BCM and the associated circuits and not in the doors.

Maybe there is a battery feed missing at the BCM. There are three fused circuits to the BCM that are direct from the battery+. Maybe pull and inspect the following fuses for condition and corrosion: Fuse# 34 TDC 10A, Fuise #28 TRN/HAZ RR 15A, Fuse #37 TRN/HAZ FT 15A. Check to make sure there is power to both sides of the fuses when installed. Also check to make sure that the turn signals and Hazards work normally.
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