2005 5.3 silverado 1500 electrical issue

taho · December 24, 2019

My truck sat for about 2 months while I was overseas. When i got home, my battery was completely dead. I had my buddy give me a jump and after a minute or 2 there was enough juice to get the truck started. Now with the issues, the only guages that work are the speedometer and tach. Fuel, Oil pressure, battery volts, engine and trans temp gauge don't work. Windows and door locks don't work. Dome light will not turn on, radio comes on but wont play any audio. Radio stays on after you shut the truck off and open the door. Radio is an aftermarket. The truck runs and drives fine. Battery charges just fine but the radio eventually kills the battery because it wont shut off. Also the Battery and ABS light are illuminated in the cluster. Hooked up 2 different scanners up to the truck and they cant communicate with the truck.

Before I left, I would get the "service brake system" every now and then but it would go away on its own. Happened maybe 2-3 times months apart from each other. The check engine light never came on but i was able to pull some codes, don"t remember exactly what they were, but it was something like "lost communication with abs module"

Gauge cluster was rebuilt in October by DRSpeedometer. With everything that is going on, I don't think there is anything wrong with the cluster.

I have an aftermarket remote start that i am able to start and monitor the truck via an app on my Iphone. I can start it, lock/unlock, see its GPS location and see the battery volts. About a month a half after i left, i lost communication thru the app with the truck and knew there was something wrong before i even got home.

Any ideas on where i should start looking?

Thanks in advance!

Merry Christmas and Happy New Year!

Mikebtte · December 25, 2019

Have you tested the battery to see if it's any good?

The alternator itself can run the truck, but that battery may have failed and you don't have enough Amps to run all the accessories

riverbanks · December 25, 2019

How about a inspection under the relay center, critter? somebody making a nest under there, chewing on a feed wire

taho · December 29, 2019

On 12/24/2019 at 8:39 PM, Mikebtte said:

Have you tested the battery to see if it's any good?

The alternator itself can run the truck, but that battery may have failed and you don't have enough Amps to run all the accessories

Battery checks good!

On 12/24/2019 at 10:26 PM, riverbanks said:

How about a inspection under the relay center, critter? somebody making a nest under there, chewing on a feed wire

No critters/nest were found. One of the first things I looked for.

After further research, seems like this is kinda common with these trucks. Common causes is the ABS/Door/SRS modules causing issues with the class2 data line and BCM.

I first tried cleaning the ground on the ABS module, that didn’t work, then I just tried unplugging the abs module, that also didn’t work.

Second thing I tried was removing the driver seat and unplugging the SRS module, that didn’t work either.

Third thing I tried was unplugging the DDM(driver door module) and it worked. My radio immediately shut off, my radio would stay on all the time. Fired the truck up and everything worked fine. All gauges worked, battery and ABS light went away, windows/door locks worked again, center dome light started working again and codes scanners could communicate with the truck. Not even a Tech2 could communicate with the truck.

I have a new/used switch on order from eBay. I went this route so hopefully it will work when I plug it in and don’t have to have the stealership program it. I’ll report back when I get the switch...