Jump to content

Silverado BCM wire diagram

Tommy Pennington
 Share

Recommended Posts

Tommy Pennington Enthusiast

Tommy Pennington

Posted
Posted

I've searched high and low, and can't seem to find a guide to the wiring for the BCM and the associated plugs located above the pedals. I have tow mirrors in the mail and I know for the clearance lights a lot of people just run wires to the front of the headlights but that seems a bit too sloppy. Has anyone tapped into anything else, like maybe a switched accessory wire? I also noticed that there are turn signal wires listed as well, are these independent of the yellow parking lights/turn signals that stay on in your headlights? Here's what I found online, but im unsure if it's reliable : Accessory purple/yellow + ignition sw or BCM under driver dash, green 25 pin plug, pin 5 , Parking Lights (-) green/gray - BCM under driver dash, white 26 pin plug, pin 22

Parking Lights (+) purple/gray (L); gray/brown ® + underhood fuse box, blue 58 pin plug, pins G1, F1 Turn Signal (Left) blue/white (F); yellow/blue ® + BCM under driver dash, brown 26 pin plug, pins 2, 1

Turn Signal (Right) green/purple (F); brown/green ® + BCM under driver dash, black 26 pin plug, pins 3, 4

 

Thanks!

  • Like 1
TJay74 Senior Enthusiast

TJay74

Posted
Posted

I will say this, be careful about adding extra wires onto existing circuits in/out of the BCM. The modules all talk on a high speed communication system called CANBUS, it is pretty sensitive to voltage/load changes that can cause issues.

  • Like 1
Tommy Pennington Enthusiast

Tommy Pennington

Posted
  • Author
Posted

http://www.gmupfitter.com/files/media/photo/578/Sierra_Silverado_Electrical_Body_Builders_Manual_Service_Manual_2015_en_US.pdf

 

Have fun, it's 898 pages but likely has what you need. I'd recommend downloading the PDF file so you have a copy if they remove the link from http://www.gmupfitter.com/.

Thanks! I appreciate it. And yes I think I have figured out that there is a wire in my door harness I can use. All I need is a switched hot.

  • 3 years later...
LifeLongWNYer Enthusiast

LifeLongWNYer

Posted
Posted

I realize this is an old thread, but I am new to the topic and have a follow-up question. 

 

I've downloaded the manual and gone though it carefully, I think, and have a question on the connectors.  I could not find a description on how to identify a connector on the fuse panel.  For an example, the left side underhood fuse panel is X50A.  The manual tells me that the wire I want is in connector X1, but which connector on the panel is that?

 

The same holds true for the other panels which have more than one connector....how do I sort out which is which?

 

Thanks for the help,

 

Jim P

Rochester, NY 

tbarn Senior Enthusiast

tbarn

Posted
Posted

Well I'll start with this. If you are using an actual GM service manual, Build your vehicle, go to Power and Distribution, then Wiring systems and Power management, then Component Locator, Click on X50 Underhood Fuse block - Bottom View.

LifeLongWNYer Enthusiast

LifeLongWNYer

Posted
Posted

I have that body builders manual, however the ONE page which i need the most is blank, with a "image not available" printed where the reverse of the X50 fuse panel diagram.  I attempted to fix that by downloading a second version, however the same page is missing.  I don't get it.....almost 900 pages, and the one i need is missing!

 

 

 

 

.

  • 1 year later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled I?    Stribeck says that we need a certain amount of viscosity under conditions of load and velocity to prevent two surfaces of a know roughness from tearing each other asunder. And we have marketing trying to tell the masses that those two surfaced require less of that commodity due to more exact limits being placed on the same old clearances. We also know that there are limits to how hard something can before it becomes to brittle to be viable and to smooth to 'wet' the surface and that both of those conditions have been known and met since about the Second World War.    That viscosity value shook out at 10 centistokes at 212 F just under a hundred years ago.  Give this a look: [Anton Parr]     What is advertised is the Kinematic viscosity (mm2/s) or that which has been density adjusted but the value we are after is the dynamic viscosity (mPa.s) or true viscosity. You can see that this number is dependent on density thus base stock and temperature. You can also see that an SAE 30 doesn't reach that value in this example. However an SAE 30 that is at the upper end of the SAE 30 range; 12.5 cSt (mm2/s), might. 12.5 * .83 = 10.375 (mm2/s). If you could find an SAE 30 at the upper end these days.   Then there is the complication of viscosity modifiers or VII or VM, whatever you wish to call them. Polymers added to very thin base oils, perhaps 3 to 6 cP oils, that will meet the SAE *W30 spec at 'tested' shear rates and 100 C/212F  target temperature. So a polymer fortified base that is a fraction of the 10 cP requirement Stribeck insist upon.   This could be all well and good if those polymers didn't have two very problematic 'features'. They shear or loose viscosity both 1.) permanently and 2.) temporality. And they do both omitted in the advertised data with the distinct  purpose of deceiving the consumer of the actual operating state of the fluid. I've shown the example of Warren Oils COSTCO 10.91 cSt 5W30 formuation several times where the 100 C HTHS value is 6.9 cP!! That's the temporary shear down and with and SSI or shear stability index of 9.4 cSt. Note the intentional deception in using mixed units?    After a short while that 9.4 cSt oil has a viscosity corrected dynamic value of 7.8 cP. But as the SSI is still within the range of an SAE *W30 whose lower value is 9.3 cSt.    This allows them to continue to call this SAE 16 weight oil a 30 weight, the cake, and still meet the API requirements for fuel efficiency IMPROVEMENT mandated by the EPA. The eating of the cake. By the time you've worn out your motor doing the responsible thing by adhering to the warranty requirements, (the stick), you get deprived of the carrot, wear control. So sad, to bad.   So what can be done? Do I need actually say? [Anton Parr]       Even this must be monitored if the oil is on the low side and the VII an organic or you opt for a 0W40 with an even lighter base oil and more / higher MW VII. (Note the lower density of the 40 weight versus the SAE 30 mono-weight?)    There is another workaround. Temperature. An SAE *W30 run at a bulk temperature of between 180 and 195 F.    Being the belt and suspenders sort I am I do both. Run it cook and run it heavy.    In Part II I'll work the AW package. 
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      So, do I go elbow-deep on this thing or list it for sale and play dumb? Seems to "runs good."   I'm about $1200 away from having: -a rebuilt injector ($300) -a new cat ($250) -a new cat back exhaust (OE style) ($300) -a new AC compressor ($200) -AC refrigerant charge ($150)   In theory, this should rectify the obvious detracting issues from its value and operability. Cold AC with a non-squeaking AC pulley both sounds and feels good. An exhaust that isn't cut/hacked in 17 different places and doesn't vibrate on a crossmember would make it sound and feel less janky. A working cat would help the stink, and will save the earth, but *if and only if* the fuel system is working properly, which would also address the intermittent "rich" CEL.   Heard a good one... CEL for "Rich condition" means you haven't spent enough money on the truck lately, and it's letting you know.   Rebuilding the injector would seem to be the most important part. Replacing the cat would be secondary. I don't think mine is plugged or overly restricted, but it might be a little restricted? I have no good way to tell other than seat of the pants feel. I hate the smell.   The current theory is I have a rich idle problem: A bad fuel pressure regulator, or a leaking injector(s) being the highest probabilities. I already replaced the FPR but that doesn't mean its replacement isn't also bad. It was a new part from Dorman, but the packaging looked like it had been sitting on a shelf for 20 years.   This is the (single) upstream O2 sensor shown at idle. I'm getting a lot of "rich" it seems. Sometimes it stays high like that and doesn't drop down. That makes me think it's processing injector leaks or a partially stuck open injector.     Other times it looks like this. Nice oscillations between rich and lean, which is what I think it should be. Under load and at speed, the oscillations are nice and tight and uniform looking, high and low.     Fuel trims suggest the PCM is compensating pretty hard at idle to pull fuel out. But it's not enough to trip a CEL. Something about slowing to a stop: brake vaccum booster, EGR, or the EVAP purge is delayed, or there's pooled fuel in the intake again that's draining into a cylinder is enough to set the CEL. Of course, in two days of driving, it hasn't set. I was hoping to actually look at the freeze-frame data when it sets. IAT is high because it's idling on an 83 degree day here.  
    • Another JR
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By Another JR · Posted

      Have considered installing a DC to DC charger in your camper to replace your isolator?  
    • newdude
      Gas fill door

      By newdude · Posted

      Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • newdude
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By newdude · Posted

      No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...