HELP - Intermittent Electrical Issues

[Oh four Tahoe]

Hi everyone!!

My Tahoe completely shut off on me while driving the other day. I disconnected the battery and reconnected it and it started right back up. Now from time to time it will start up slow and then when it starts the right side of the dash board doesn’t work. The AC and power windows don’t work and my back up camera stays on. The dome lights also stay on during this time.I have to disconnect the battery multiple times and then it will work for a few days and then happen again. Do I need a new battery? Ground wire? Any suggestions would be appreciated. Thanks.

 

[Oh four Tahoe]

Few pictures

 

[TollKeeper]

Sounds like either a ignition switch has gone south, or a faulty ground.

The ignition switch is a common failure, and easy to replace. I dont recommend using a Dorman, try to find a ACDelco, or a Delphi branded.

 

[Fless]

Define "start up slow." Slow crank (turning over)? Good crank but long crank before it fires up and runs? Runs like crap initially but smooths out within a minute or so?

 

[OR VietVet]

What @TollKeeper said but let's start with the basics. How old is the battery? Dirty, loose, corroded battery connections/cable ends? Condition of the battery? Charges ok and stands up to a load test? After charging, test voltage and should hold/be at, at least, 12.6 to 12.8 volts and then load test.

 

[Oh four Tahoe]

Define "start up slow." Slow crank (turning over)? Good crank but long crank before it fires up and runs? Runs like crap initially but smooths out within a minute or so?

Slow cranks and then fires up. If it does the slow crank then it will do all the things stayed above. If it starts up normal everything will run great.

 

[Oh four Tahoe]

What @TollKeeper said but let's start with the basics. How old is the battery? Dirty, loose, corroded battery connections/cable ends? Condition of the battery? Charges ok and stands up to a load test? After charging, test voltage and should hold/be at, at least, 12.6 to 12.8 volts and then load test.

Battery is 4 years old. Clean cable ends. Battery condition is good but 4 years old. Just noticed with everything running and holding the window switches up the batter drops significantly

 

[OR VietVet]

Battery is 4 years old. Clean cable ends. Battery condition is good but 4 years old. Just noticed with everything running and holding the window switches up the batter drops significantly

How do you know battery condition is good? Did you open up the cable insulation, close to the cable ends and look for corrosion?

 

[Fless]

Let me see if I understand this:

At times the engine cranks (turns) over at a good speed, then it fires up and runs.
Other times the crank speed is slow, then it takes a longer cranking time to fire up and run. Does that describe it?

I would suggest disconnecting the battery, using a good battery charger on it, then having it load tested. The battery is old enough to be suspect and the symptoms point to a dead or compromised internal cell, bad battery cables, or both.

And as @OR VietVet noted, the battery cables can rot from the inside out, but can look fine on the ends.

 

[Doubeleive]

voltage drop test to starter 10.5v is no good

ground test to starter

if both pass then probably fried starter
pull it and bench test, but that would have no load so ??? might not show symptoms
but there is really no reason for a slow crank if voltage and ground is solid, the starter is it's own beast unless the motor is seizing up

 

[dwinters14]

Sounds like an electrical issue. You could have an intermittent short to ground/short to power which is adding a ton of resistance to the system making it hard to start/keep power going through the system. In terms of the lights and back up camera staying on, I wonder if that's any aftermarket components you have installed? The fact that you removing the battery terminal and re-attaching seems to temporarily fix it, could point to the system being reset.

Rule out your battery first.

Confirm it's good, then tighten all your connections. Positive terminal, negative terminal, engine to ground, positive to alt, and positive to starter. Ohm test your grounds, battery to ground, and engine to ground. You will be able to see if there's something internal going in with the wire if the resistance is very high or not consistent, this would be good under load.

Next the only other thing that connects ALL of those components is your ECM/PCM. Could be a short in the system there which is causing all the random crap going on. I'm not exactly sure how it all lays out on your truck, and it'd be tough without a diagram but see if the smaller modules (AC, windows, starter, radio) all connect to the bigger ecm.

Could be corroded wires, loose pins, shorts etc... but it definitely sounds electrical to me.

GL!

 

[51Davek]

Everyone talks about the cranking issue and not the lights and shutting down. It appears to me that there may be an issue with the Body Control Module. And it may not be the unit itself, but, a short in the network. Check the condition of the HVAC front fan. If the resistor shows signs of burning, this may be the problem. Sounds weird, but I had the same issue. And after $2500 and replacing many parts. This resistor was my problem.

 

[tc8510]

I have had these same issues as you back in 2021. It was killing me. Where the truck shuts down while driving or doesn't start randomly, especially after rain. I had someone look it over for me. The very 1st thing that he checked, were all the ground wires. Come to find out it was the one under the hood that connected to the engine block. It was on its last thread literally! He replaced it and has not had an electrical issue since. I hope this helps... Good luck!!!

 

[JayHow]

I also had very similar issues recently and it was the ground strap from the firewall to the rear driver side of the engine block.

I ran a new ground from the firewall to the engine block, on the mounting bolts for the alternator. Also ran a new ground from the negative battery terminal to the other mounting bolt for the alternator. Most people do this when installing aftermarket sound systems so I just copied a "Big 3 Upgrade" video and I have had no issues since.