Electrical Gremlin causing multiple problems

Ralph Watty · June 8, 2020

Multiple issues I think stem from same problem as they happened almost simultaneously: front diff doesn’t engage 4wd; dead battery after sitting for at least 3 days; steering pulling left or right when decelerating or accelerating (electric power steering). Thinking some electrical or computer issue is to blame for everything.

2017 RCSB Silverado 5.3 4wd WT (manual T-case). Heads, cam, DOD delete, Whipple, LT headers, upgraded ignition system, etc. Also, Odyssey battery, 300amp alternator, small stereo system (1800 watts w/factory infotainment 8” screen).

I replied to an off topic post in this forum with my issues, and after performing some troubleshooting on my own. But after searching for solutions I’m left with the same problems and no direction on how to proceed.

Troubleshooting so far:

1.) verified that transfer case is engaging properly. It is.

2.) checked to see if the front diff actuator is engaging the front diff. It is not.

3.) checked 4wd Trec fuse visually and with continuity test. It is perfect.

4.) performed amperage draw test at the battery negative terminal and found 5 amp draw with key off.

5.) disconnected the 3 fuse boxes - under hood, leftside, right side - to pinpoint which fuse box has thecircuit drawing power. Right side fuse box at dash is source.
6.) pulled infotainment fuse. Door speakers made a popping noise. Battery draw reduced to 0.01 amps.

So, I know the source of the drain but unsure what to do next. I thought BCM would monitor battery drain and prevent the truck from going dead. So, I think I have a BCM issue that’s also affecting the 4wd actuator and electric steering logic. Thoughts on what to do next?

Eddie 70 · June 8, 2020

Sounds like your amp must not be turning off when you turn the truck off. I don't know how you have it wired but when you pulled the fuse to the infotainment system it let you know it had been powered on. A 5 amp draw is a big draw. This kind of draw will kill a battery in 3 days time. A weak battery has been known to cause issues. I don't know much about stereo systems but it seems to me that the trigger wire is keeping the amp turned on.

Ralph Watty · June 8, 2020

I thought amps were draining battery too.

they get signal/remote wire from the factory infotainment/radio.
Pulled fuses from amps. Disconnected power wire from amps.
2.5 amp draw from infotainment still exists. Remove infotainment fuse and battery draw drops to 0.01.

Noticed some other things, but unsure if it’s normal: opening passenger door doesn’t turn the accessories off, but opening the drivers door does turn everything off; opening the drivers door after the truck has been off for several hours turns on the dashboard (gauge cluster, infotainment center, climate control knobs and buttons). Is that normal?

Also, pulled dash area by dash speakers and verified G218 and G210 grounds were good.

Keep thinking BCM isn’t going to sleep like it should. Which leads me to think there is some stupid little part that isn’t sending a trigger signal like it should.

JimCost2014 · June 8, 2020

1 hour ago, Ralph Watty said:

Noticed some other things, but unsure if it’s normal: opening passenger door doesn’t turn the accessories off, but opening the drivers door does turn everything off; opening the drivers door after the truck has been off for several hours turns on the dashboard (gauge cluster, infotainment center, climate control knobs and buttons). Is that normal?

That is all normal.

Ralph Watty · June 8, 2020

Thanks for letting me know.
I can stop going down that rabbit hole now.

Just weird to have multiple problems arise almost simultaneously. So, I thought they must originate from a single source.

Have a transfer case position sensor on order to see if that solves the 4wd issue. Will unplug the EPS to see if that eliminates the unpredictable steering. Have a call in with my stereo installer to see if he has any insight for battery drain. Meanwhile, I just have the fuse removed.

any other guidance still open for!

JimCost2014 · June 9, 2020

5 hours ago, Ralph Watty said:

Thanks for letting me know.
I can stop going down that rabbit hole now.

Just weird to have multiple problems arise almost simultaneously. So, I thought they must originate from a single source.

Have a transfer case position sensor on order to see if that solves the 4wd issue. Will unplug the EPS to see if that eliminates the unpredictable steering. Have a call in with my stereo installer to see if he has any insight for battery drain. Meanwhile, I just have the fuse removed.

any other guidance still open for!

You are very welcome.

Have you gone through all of the ground points?

Ralph Watty · June 9, 2020

G218 and G210 under the dash are good. I haven't gone through the rest. Not sure where they are.

Ralph Watty · June 17, 2020

Update:

Everything seems to be working correctly now.

1.) Front diff actuator replaced and 4wd is working properly

2.) Performed a relearn of the PSCM. For some reason the rack and the steering wheel lost center and each other's position. Truck no longer wandering on acceleration and deceleration

3.) Reset the BCM and cleared all codes, and it seems to have remedied the battery drain issue.