2004 Chevrolet colorado z71 3.5 4x4. Heater/fan,turn signal,brake lights intermittently flash on and off. Suspect bcm but don't know where bcm is and if it needs to be programmed when replaced

There isn't one. The function is done by the Body Control Module (BCM) along with lots of other functions.

Where is the turn signal relay on a 2006 Chevy Colorado?
The turn signal is controlled by the BCM (Body Control Module) that is located at the passenger side kick panel.
May 21, 2014

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Your hearing it coming from the diver side front speaker . There is no relay , the BCM - body control module makes the turn signals work . What problem are you having ?

Turn Signal Lamps
The FRT TRN/HAZ/CRTSY/MIRR/CARGO and REAR TURN/HAZ fuses in the underhood fuse block supplies battery positive voltage to the body control module (BCM). When the turn signal switch is placed in either the left or right position, a signal is sent to the BCM to illuminate the desired turn signal lamps. The BCM has an internal flasher that sends an ON-OFF voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, a separate ground signal is sent to the BCM to activate and flash all turn signal lamps including both IPC turn indicators. The front and rear turn signals are grounded at G105.
The IPC illuminates the TURN SIGNAL ON indicator in the driver information center (DIC) when the IPC determines that the turn signal is active for more than 1.2 km (0.75 mi). The BCM sends a class 2 message to the radio in order to activate the audible warning.

Your best bet , take it to a qualified repair shop.

In the diagram for rear lamp, the top wires are voltage, the bottom black wire is ground. The brown wire on either side should be tail lamps, goes hot when you turn on the headlamp switch. The other top wire on either should be for turn signal. With everything turned on, is there voltage on that wire?
Because the front works and the rear don't, possible wiring circuit problem? The voltage for turn signals comes from bcm. The bcm knows when you turn on turn signal switch, either side, then the bcm sends voltage to turn signal lamp at the rear and front.

Sometimes the housing the bulb is in has gone bad try cleaning out the prongs where the bulb goes in it that does not work replace the fixture the bulb goes in had the some thing happen to my trailblazer hope this helps

It can be loose wiring or issue with bulb or the battery is weak or brake light socket getting short somewhere.Car lights getting dim,there are many such common issues noticed.I will share some familiar help links,related to your problem.
Click the link below:---2004 Dodge Ram: High Beam Light is DIM? http://technoanswers.blogspot.in/2012/04/2004-dodge-ram-high-beam-light-is-dim.html
----------Ford Odometer Dims intermittently http://schematicsdiagram.blogspot.in/2012/07/ford-odometer-dims-intermittently.html
---------Turn Signals Don't Work When Brakes Are Applied? http://schematicsdiagram.blogspot.in/2012/04/2005-gmc-envoy-turn-signals-dont-work.html
--------
Brake light Switch Location? http://schematicsdiagram.blogspot.in/2012/04/1996-buick-regal-gran-sport-brake-light.html
----------- No brake lights on Buick? http://schematicsdiagram.blogspot.in/2012/04/no-brake-lights-on-buick.html
----------- Brake lights not working on 1989 BUICK REGAL? http://schematicsdiagram.blogspot.in/2012/04/brake-lights-not-working-on-1989-buick.html

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These will help.
Thanks.

Not sure, but I've heard a bad hazard switch can cause strange problems.
Also, if your truck has a body control module that controls interior and lights, that may be your problem, too. Good luck.

Replace the turn signal switch. They can be fixed if your up to it, but you have to disassemble the switch. there are parts that have to go back in the right order. Let me know. The longer you let this go , you will start to lose the headlights. All the outside lights run threw the turn switch.

I suspect there is a problem with the turn signal/ hazard switch. turn the turn signal on left or right, if it doesn't flash, grip the hazard button and gently wiggle it around, if the signals start flashing, replace the turn signal switch. The Brake lights are wired through the turn signal switch, if the 3rd brake light works, the brake switch is OK. I don't think it has anything to do with the anti theft system (at this time)

As for the brake lights push brake pedal down while pushing on and wiggling the hazard switch.If the brake lights come on then replace the multi-function switch.

your turn signals go thru the BODY CONTROL MODULE.its located on passenger side kick plate down where you feet are.i dont think that is problem ,but its is sometimes.i am not sure where sound comes from,i assume its behind the instrument cluster.BCM is like computer in your truck.turnsignal relay is in there.