Doggone Electrical Issues... Probably self made but trying to resolve.

'03 Z71 Avalanche 1500...

So when I installed my dual battery system I used a Solenoid to connect it to my charging system.

Apparently the factory alternator isn't liking charging two batteries. I bought a 250 amp alternator (One suggested by MS03 2500) but this alternator is only marginally better than the factory alternator. (At 1000 rpm its only putting out like 40 amps. 2000 RPM is like 70 amps.. To get 250 amps you have to be spinning it at 6000 RPM) Still showing only 13.8 on the system when running with the new alternator.

Probably has something to do with my ~1600 watt stereo system and having two batteries in the system.

Anyhow, my main battery died and so I jumped the coil on the solenoid to jump start the truck. This worked fine. However I seem to keep killing the main battery and did this a couple more times.
Unfortunately I didn't think much about it and never put a diode in the solenoid coil line. I had this connected to the SEO/Ignition lead in the under hood fuse panel to charge the coil when the truck is running.

So a couple weeks ago I started having issues with no power when the key is on. Did the jumper thing again thinking it was a dead battery again. (Starting to think I am having a parasitic drain from somewhere. ) Left my clip in place, charged up the battery for like 10 minutes and turned off the ignition. However the truck continued to run... After cussing a couple times I pulled the jumper off the solenoid and the engine died.

So last week the truck has been hit and miss. Sometimes it would start and others not so much. No power at all.

The last time I did the "jump the truck" trick to get it to start I blew the 10 amp fuse I was using to power up the solenoid. Truck did start but not sure what is going on now.

Replaced the Ignition switch with no change.

Not sure where to go next other than to possibly pull the under hood fuse panel and check for damaged wiring. Will also follow some trouble shooting and see if I can figure out where the power is stopping.

As to the under powered alternator... I am looking at doing one of two things... The original alternator was working fine other than under sized.
Since the 250 amp alternator was like $130 I could return it and purchase a new better high powered alternator for like $500-600 or grab a dual alternator bracket for $300 and run the factory alternator for the normal stuff and run the 250 for just the stereo system. Each its own battery.

Thinking if I go with dual alternators and I decide to add additional lighting and such I could at that time pick up the better high powered alternator and move the 250 in place of the factory one.
I will likely keep the solenoid but have it only for jumping the truck if the main battery is dead.

So once I have this sorted out I need to figure out possible parasitic drain. I have heard of issues with Starters with the solenoid staying partially engaged but not enough to actually engage the starter.

Guy at work also told me if the fuel pump is not working properly it can send an issue back to the PCM which can cause the no power issue but seems wonky to me. He said it happened in his '04 Suburban where he turned the key on and no power with the battery still good. Ended up being diagnosed as the fuel pump was not returning a required signal telling that it was running and so the truck did not power up when key was turned on When the truck powers up when turning the key the truck runs great so not sure what the deal is there.

Hoping someone has an Idea...

Without reading the entire post did you do the big 3 upgrade

MS03 2500 said:

Without reading the entire post did you do the big 3 upgrade

Click to expand...

Original Battery has original wiring except I upgraded the Alt to Power tap to 4gauge.

Using 1/0 gauge wiring from secondary battery to stereo distribution panel.

Using 4 gauge wiring from Power Tap to secondary battery.

Believe original OEM wiring is only 6 gauge to the starter and like maybe 8 gauge to the under fuse panel.

Since the only thing from the audio system still on the old wiring is the radio I have not been concerned with upgrading the OEM supply wiring.
Wiring is still in decent shape with no corrosion issues.

Ok I have decided to fix my electrical problems once and for all.

Mechanic buddy mentioned that the RPM values for the Alternator are for the RPM of the alternator and most alternators are 2:1 so maybe the "cheapie" alternator isn't bad after all.

With that in mind at 2000 RPM ( Assuming 1000 engine RPM) is 76 amp.
3000 RPM = 185 amps which would equate to 1500 Engine RPM
4000 RPM = 227 Amps which would equate to 2000 engine RPM which is about where my truck is most of the time while cruising.

So what I am currently seeing...

Voltage at Alternator 14.5
Voltage at main battery with stock wiring (4 gauge wire from alternator to red box)  13.8
Voltage at secondary battery using 4 gauge wiring from red box to solenoid with 2 circuit breakers in circuit.  13.8 volts.

So looks like my best bet will be the big three upgrade. I have seen suggestions that one ground the battery directly to the alternator for the best charging voltage.

I have a parasitic draw as well... 5.5 amps by the looks of my VOM. This is new and I wouldn't be surprised if related to how I was backfeeding the ignition system.

I pulled some fuses and got some interesting results.
Pulling the MBEC fuse drops the amperage to 2 amps immediately.
Pulling the DIC/Cluster fuse drops it to 4.5 amps initially then to 2 amps.
Pulling the Radio fuse drops to 4.5 amps initially then to 2 amps.

Pulling the MBEC fuse after the radio fuse does nothing.
Pulling the MBEC fuse after pulling the DIC/Cluster fuse drops me to .08 amps.

So looks like my cluster has an issue. My guess is that it is not sleeping for some reason and "keeps everybody else awake". Need to track down the MBEC fuse yet.
The .08 amperage is likely reasonable due to the aftermarket alarm on the truck.

This is a new thing that has been going on over the past month so we shall see... Will talk to the "dashdr" and see if he can check out the cluster to see what happened with it.  And will continue to track down what I can.

Suggestions welcome?
(Reasonable ones related to the issue to help resolve it... )

Also, is there a thread about doing the big three upgrade?

Rodney

Before I purchased a new (rebuilt) cluster from Digital Dash Solutions, Inc. a couple of months ago, my old cluster was doing some really weird stuff.

For one, sometimes if you walked by the truck while it was really dark outside, you could look at the DIC through the driver's window and there would be some low light gibberish on the display.

Other times, not.

One of the most consistent things you would see, would be as soon as you opened the driver's door, a brightly lit bunch of gibberish characters would flash brightly on the display for around 5 seconds, or until you turned the key on.

After the key was turned on, the normal characters you would expect appeared.

Replacing the old cluster fixed all of these and some other weird issues.

But my point is, the cluster absolutely has power running through it, in some form or fashion, with the ignition in the off position and when the truck is shut down and the doors are closed and locked.

I don't know if this helps any, but there you go.

Perhaps you could unplug your cluster during your search for the power leak.

It ended up being the MBEC fuse. If I pull that fuse and wait 5 minutes my amperage drops to .06 which sounds about right with my aftermarket alarm that has an internet connection to it.

So now on to figure out what is causing that fused circuit to use up power.

I have power everything so I need to pop fuses and such. Was 95F here and was also working on sprinkler system so I put off diagnosis on the fuse until later.

From what I can tell the MBEC fuse powers a relay panel left of the steering column and the seats too.

Since I have been moving stuff around for the new 1/0 gauge wiring anything is possible.

So what I can tell is I need to leave the battery disconnected, pop open the MBEC panel, pop out some components (Relays/fuses), close the door and then connect my VOM. Since I am seeing almost 6 amps with nothing going on I will pop the fuse in my VOM if ANYTHING is going on. Considering grabbing a DC amp meter that you clamp over the wire. Harbor Freight probably has them.