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Gary
Gary, ASE Certified Technician
Category: GMC
Satisfied Customers: 16384
Experience:  GCM master tech over 25 years
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My keyless entry wont work so when ulocked with the key the

Customer Question

my keyless entry wont work so when ulocked with the key the alarm goes off and wont let me start the truck
Submitted: 1 year ago.
Category: GMC
Expert:  Gary replied 1 year ago.

I am sorry for the long wait

this is the stock key less entry system in this truck and stock remotes that came with the truck ?

and BOTH remotes will not work ?

Customer: replied 1 year ago.
This is correct I only have one remote when I unlock the door with the key and put it in the ignition and try to start the truck before the 10 seconds is up nothing happens and the alarm system is still blowing the horn
Expert:  Gary replied 1 year ago.

so the truck will not physically crank over at all ?

this truck has 2 theft systems so to say

one does not allow the truck to start up it will crank over physically and not fire up

and the other will blink the lights and beep the horn but should still physically crank over the engine and start up

Customer: replied 1 year ago.
Won't crank at all motor does not turn
Expert:  Gary replied 1 year ago.

this sounds like we have more of an issue than the remote not working

if you connect jumper cables or remove and have the battery tested for volts and for cold cranking amps and for bad cells will the battery test out good for those things ?

did this problem happen out of the blue one day ?

Customer: replied 1 year ago.
The anti theft system is locking everything out yes it just happened out of the blue
Expert:  Gary replied 1 year ago.

no matter which theft system is activated that engine should still physically crank over

if that battery tests good can you put your fingers on the relay called STARTER in the under hood fuse box and do you feel that relay click with your fingers every time the key is held to the crank position ?

if not this issue is going to come down to a bad BCM which activates the horn and the blinking lights in that 1 theft mode and gets the signal from the ignition switch that you are trying to crank the engine and then will tell the ECM to activate the starter relay

again neither theft system should stop this engine from physically cranking over

Customer: replied 1 year ago.
I have no radio functions and cannot unlock the doors with the door switch and no response from the blue onstar button
Customer: replied 1 year ago.
Pass lock maybe?
Expert:  Gary replied 1 year ago.

all of those things are controlled by the BCM

can you remove and have the battery tested ?

pass lock will only shut off the fuel injectors it will NOT stop the engine from physically cranking over

Customer: replied 1 year ago.
Where is the bcm located
Expert:  Gary replied 1 year ago.

it is located as seen here

but if replaced it must be programmed with a programming scan tool and the programming from a computer into the scan tool to your trucks VIN number

dont forget to rate us here at Justanswer as i do not get credit for my work until you rate us here

Expert:  Gary replied 1 year ago.

how are you making out ?