Flashing/pulsing exterior and interior lights

[upther]

I'm kind of stuck here since I've gone through all the normal culprits.

When the truck is running and the headlights are on, they pulse. The longer it sits idling, the more they turn into a flash. They never go completely off, they just sit there and flash. The interior lights will do the same thing. Once I start driving, everything seems fine. Until I stop and the pulsing starts up again. If I turn the key to on without starting the truck, the lights and everything work just fine. No flashing or pulsing. Leads me to believe the battery is fine.

I took my volt meter out and checked the battery anyway and it was fine. I went to Advanced Auto and had them check the electrical system. The only problem they noticed was that the starter voltage seemed a bit low.

I'm going to replace the elbow that causes everybody problems, I do have some occasional rough idle, but I'm not sure if that has anything to do with the electrical issues. I took a look at it and don't see any cracks but obviously can't see under neath it.

Any thoughts?

 

[bdmaash]

check grounds, if they are ok. Charging system - alternator

Does starting voltage = cranking, if it is, then the battery needs replacing since it doesn't have much capacity

 

[upther]

Well, it wasn't the battery. I hooked my volt meter up so I knew the old battery at least had the proper charge on it but there was no label on it anymore so I had no clue how old it was. Mainly changed it just for peace of mind.

 

[bdmaash]

unplug the daytime running module, see if the interior lights stop pulsing.
most likely it will be a power issue - weak ground/power connection.

 

[4pullingGM]

I had a F250 super duty that something similar, all of the lights would pulse (headlights, interior, dash, running), the alternator light in the dash would faintly flicker as well. Charging voltage checked good. Checked a bunch of stuff, long story short, I ended up and found the harness between the battery and alternator had high resistance where the fuseable link was spliced in. When it was running, it would actually get noticably warm, thats how I ultimatly found it. I'd run a voltage drop test on that wire.

 

[Pameypoo]

I had a F250 super duty that something similar, all of the lights would pulse (headlights, interior, dash, running), the alternator light in the dash would faintly flicker as well. Charging voltage checked good. Checked a bunch of stuff, long story short, I ended up and found the harness between the battery and alternator had high resistance where the fuseable link was spliced in. When it was running, it would actually get noticably warm, thats how I ultimatly found it. I'd run a voltage drop test on that wire.

What did you do to to fix it? Having this issue with a pre owned Explorer that I just bought.

 

[koda2000]

Possible bad voltage regulator (which is part of the alternator). Check the connections and likely replace the alternator.