I have a weird issue that i have had from day one on the truck and its about to be 3 years old. I wonder if i need to take it in before warranty expires but i have had so much run around that i hate to do that. Here's my situation:

I leave work every morning when its still dark. I pull out of the garage, let the truck warm up 2-3 minutes and then pull out of my driveway. At the exact same spot (approx 60-70 ft from my driveway) as I am accelerating the headlights seem to flutter a little that resembles loose headlights when hitting a bump. That is the only time it will do it the rest of the morning. I noticed it the other night when i was leaving the in-laws house, the truck had been sitting in the driveway for a couple of hours and when i started out of the driveway to head home, approx 60-70 ft away and it does it again. Only one time when you first take off but it will flicker (or flutter) about 5 times real quick and then its over with. I have tried letting the truck warm up for 5 minutes and still the same thing.

So what could be the issue? It didnt bother me at first but since the warranty is about to expire i thought i may need to take it in. Any thoughts?

BTW, i tried a search on this here and came up with nothing on the first 3 pages. I don't have the extra time to search all posts related but thought the most recent would be better matches.

Thanks all.

 

A simple way to test it is to hook a small 24-30 gauge long wire to a multimeter from your lights and see if you are getting any voltage issues. I'd suggest having a passenger watch the mm, and not the driver. Then approach the dealer with your results.

 

I may have to try this. I did some more testing this morning and when I dropped my youngest off at daycare, I shut the truck off this time. It did it again. When I came to a red light just down the street I shut it off again and it repeated itself. Whats, weird is that it only does it on the first acceleration after startup and it is always during second gear between 1500-2000 rpm's. I may call another dealer today to see what they say. I'm sure it will be "Bring it in and leave it and we can check it out".

 

Hi.

One headlight, or both? This is a key piece of info to nail first before going any further.

If only one - look to the wiring, socket, bulb, etc for that side.

If both - I suspect something common like the SJB, grounding, MFS, etc

BTW - next time, try it with the highbeams on instead - this will yield another piece of data that may help diagnose.

Lastly - some DVM's won't respond fast enough to notice a rapid voltage change - you may need an old-fashioned analog meter, or even a plain old test light.

EDIT - just a thought - do you feel yer ABS initializing/calibrating at the same time? This only occurs once certain conditions are met - truck in drive and has moved several feet. Just wondering if that draw is causing a drain on something - cause or effect. Yer battery is healthy right? Having difficulty explained the on-shot nature of this issue. You'd think that if it was a loose connection it would happen randomly.

Ahhhh ... need coffee, ignore my gibberish, lol

Good luck
MGD

 

Ok, its both headlights and it does do it with high beams on as well. I tried that last night. But here is something else, and it may help with the diagnosis. As i was leaving the in-laws last night, i tried with the high beams on and yes, it happened again. But also, there was still a little patch of snow/ice in the neighborhood so i thought i would play a little and slide around. Thats not typical of me but i had been painting all night and needed a pick-me-up for the short drive home. As i was spinning, you could hear the traction control working and at the same time the headlights were flickering too. I wonder if you are on to something with one of the above mentioned suspects?

BTW, what is SJB and MFS?

 

The ABS module does a self-test every time you start the vehicle and begin to roll (it may happen the first time you hit a certain speed or a certain distance travelled). Try stepping on the brakes during that moment and you'll feel the pedal pulse. I would suggest it is completely normal as the abs pump and solenoids would be quite a large electrical draw.

 

As is traction control.



Sorry fer the late response, OP - I been testin'!

Thanks for the observations, OP. This eliminates a whole bunch of stuff. Not much left.

I don't think it's normal. The electrical bus should be stiff enough. I tried to duplicate this ( easy since we have slippery crap all over our roads). Hooked up an ol' analog Simpson voltmeter, and a test light. Induced ABS function at will. Negligible voltage drop at the headlight. No discernible flicker on the test light. Sorry - didn't have time to datalog the electrical system to get a continuous bus voltage level. (SCT handhelds can do this).

I suspect grounding or a poor connection (not loose, just high resistance ) as something is introducing a voltage drop in that bus, and a small series resistance would do it.

As long as a cell isn't starting to go in the battery that is.

Oh - MFS = multifunction switch. SJB = Smart Junction Box ( lighting controller passenger kickpanel )

MGD

 

Did the OP ever find out what was causing the issue?