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1995 gmc Sierra 1500 4x4 headlight electrical issue

K

Kkerr

New Member
Messages
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Location
Bellingham WA.
My truck starts up fine with no problems. I have a new battery and the battery gauge says it is closed 14 volts. When I turn my parking lights on, the gauge drops 1-2 volts and i turn on headlights it drops even further. Checked alternator and battery already. Just seeing where a good starting to narrow the problem down?

Thank You for reading
 
Remove and clean battery cables, load test batteries while cables are off. If you dont have a load tester, after cleaning drive to autozone or similar for them to test.
 
Sorry, got swarmed by trick or treators.

Once that is verified- you need to inspect and ohm out the cables.
How fast does it recover from lower voltage when you turn back off headlights?
 
The truck was sitting for 8 months. I needed to get a new battery and radiator. I replaced them and notice the drop in my battery gauge when using any accessory but notice a big drop when using lights.
 
Talk to Chris about the radiator- get a killer one that is coated and be set!
I am a firm believer in agm batteries. Optimas keep working amazingly long for me, even since the move to Mexico
 
Haha- ok sorry I missed the “ed” though you said need.

This really sounds like what I just went through on the wifes truck. It turned out to be the battery was goofing up. But it was dying a slow drawn out death. What I did was drained the crap out of it and had it recharged at Oriellys with their $10,000 testing unit since it was under warranty. They finally replaced it and the new battery solved the issues.

That is a 6.0 gasser with only 1 battery.

Which leads me to question time.
Please fill out you signature like ours is so we always know what rig and what modifications we are dealing with. Are you in a gasser, diesel, 1 battery or 2, what year, what modifications, etc.?

battery cable age / condition?
Pics never hurt and sometimes a different set of eyes spot things.
 
Start with cleaning all Grounds no matter what they look like. Then use a volt meter to start checking voltage drops across cables and wires. With the engine running the voltage/current should come from the alternator. Bats should be out of the picture - keep this in mind when tracking the voltage drop down. The alt also has a sense wire to raise voltage for any voltage drops on the alt charge wire.

Clean fuses as the contacts can oxidize.

Is the ground strap from engine to body behind passenger side head present and in good shape? Add ground strap from engine to body and engine to frame. (Use bolts and locations that don't have other wires on them!) Leave batteries out of any new ground straps because they start the engine and then are a only 6A load each for charging from alt. Ground loops will result if you touch the batteries for additional grounds: JUST DON'T DO IT.

Get a relay kit for the headlights... Still need to track bad connection down. Note the old gauge can be ultra sensitive so make sure by your volt meter you really have a problem.
 
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