Electrical Shenanigans

[gfluff]

2007 4.7 V8, 108K

Turning the headlights on now lights up the dash like a Xmas tree, with the Brake, ABS, Trac, and 2 more orange lights on. If I pump the brakes while sitting, the warning alarm also sounds, like the master cylinder is dying. But my brakes are currently functioning fine..
-without headlights on, truck is fine, BUT if I pump the brakes while sitting, all the lights come on and alarm sounds for a second or two, then it all goes off.
-LED headlights went in 6-8 months ago?
-has gotten significantly worse since a long off roading trip, maybe something was bounced loose?
-hoping it’s an alternator not putting out enuf juice to keep the MC motor happy?

Thoughts? I’m going to look into it more tomorrow...

 

[gaber6]

Wow I literally had just the same issue.
I had three problems. My aftermarket amp ground had come loose, my third brake light was out and I feel like my brake switch was failing.

Most likely one of those. I still have some fuzz through my aftermarket sub and will likely just get new rear door speakers and remove the amp. I hate the room it takes up behind the driver seat.

 

[Wild Thing]

Did you drive through a colony of gremlins during your offroad trip?

Pesky devils, especially if you run one o' the li'l bastards over.

They've loved the electrical systems on every damn vehicle I've owned.

 

[Burt]

Have your alternator/battery checked. Either you battery is shot or alternator has low output. Not enough to charge battery.

 

[gaber6]

Have your alternator/battery checked. Either you battery is shot or alternator has low output. Not enough to charge battery.

This actually is what I'm looking at now on mine too.
It is NOT the amp or radio failing as I have the fuses out and it is still triggering an electrical glitch when I use the brakes or flip on the fog lights.

I measured the battery terminals with the car idling and it is only 13.4 volts. The battery is old, but I'm assuming I can get the alternator tested while in the car still?

 

[Warwicke36]

This actually is what I'm looking at now on mine too.
It is NOT the amp or radio failing as I have the fuses out and it is still triggering an electrical glitch when I use the brakes or flip on the fog lights.

I measured the battery terminals with the car idling and it is only 13.4 volts. The battery is old, but I'm assuming I can get the alternator tested while in the car still?

Did you do this with the headlights on to replicate the issue? the current load is different and will identify the issue if you load it up with headlights ETC so the problem is present when testing.

An alternator must be tested in the vehicle with a good battery. The battery should be tested with a proper battery tester or full charge with a load pile tester (but I prefer the first method)... If battery proves bad replace it and then test the alternator.

13.4 volts is charging fine but make sure it can do that with the headlights on, sound system on (esp if modified) and heater blower motor at full... essentially load up the electrical system and make sure it can keep up.

check battery connections and ground connections too.

 

[gaber6]

I keep headlights on all the time.
The issue happens when driving. Feels like bigger blips of energy into the dash the faster I'm going.

It does feel like a ground somewhere going bad, but I did have a few slightly longer crank days, so it may be a failing battery. Never hurts to replace that before I need to when it gets to be 20 degrees, then I can go from there.

 

[gaber6]

I did just get the battery checked and it was at 300 CCA and was manufactured in 2017, so it was due for a swap. Drove around and no glitches so far. If the gremlins come back, I'll get a new alternator.

 

[gaber6]

2007 4.7 V8, 108K

Turning the headlights on now lights up the dash like a Xmas tree, with the Brake, ABS, Trac, and 2 more orange lights on. If I pump the brakes while sitting, the warning alarm also sounds, like the master cylinder is dying. But my brakes are currently functioning fine..
-without headlights on, truck is fine, BUT if I pump the brakes while sitting, all the lights come on and alarm sounds for a second or two, then it all goes off.
-LED headlights went in 6-8 months ago?
-has gotten significantly worse since a long off roading trip, maybe something was bounced loose?
-hoping it’s an alternator not putting out enuf juice to keep the MC motor happy?

Thoughts? I’m going to look into it more tomorrow...

Any luck? Did your LED headlights come with any adapters to dissipate heat or were they direct plug in?

 

[gfluff]

No luck. Ran to AutoZone, who did a quick test and said battery was ok, at the low end of good. No alternator test. I may try a different shop this week, I ran out of time yesterday. I went under the hood and jiggled wires, and I disconnected and blew out headlight connectors. No change. They don’t have extra things to dissipate heat, but they do have fans built into them. I may try going back to the original bulbs to see if it makes a difference.

Today I get in the truck and the TPMS comes on. I checked all 5, just the spare was low. Added air, went to crank it back up, and the crank decided it was done. Wont budge. Wired it up, spare in the trunk for now. Time to finish the swing out tire holder, I guess...

 

[Warwicke36]

No luck. Ran to AutoZone, who did a quick test and said battery was ok, at the low end of good. No alternator test. I may try a different shop this week, I ran out of time yesterday. I went under the hood and jiggled wires, and I disconnected and blew out headlight connectors. No change. They don’t have extra things to dissipate heat, but they do have fans built into them. I may try going back to the original bulbs to see if it makes a difference.



Today I get in the truck and the TPMS comes on. I checked all 5, just the spare was low. Added air, went to crank it back up, and the crank decided it was done. Wont budge. Wired it up, spare in the trunk for now. Time to finish the swing out tire holder, I guess...

You may have a module going bad or a bad wire on the can bus network. Happened to one of my Escalades. It ended up being a bad suspension module which took down the high speed can bus network. Had all kinda of lights on on the dash, start stall sometimes ran sometimes didn't, sometimes wouldn't crank. I suspect the same is going on here. Unfortunately these are difficult to diagnose.

Sent from my SM-G950U1 using Tapatalk

 

[gfluff]

Pulled all the LEDs out, no more warning lights...fingers crossed...