Dimming Headlights.
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Junior User
Joined: Jan 2004
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From: iowa
Dimming Headlights.
On extreamly cold mornigs, I have noticed that while going down the highway that the lights dim. The headlights and dash lights as well. It seams like something is kicking in and drawing down the juice in the truck.It was -15 deg this morning. I've noticed it a few times now in cold weather. Has anyone had this happen or heard of this.
steve
steve
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Joined: Jun 2004
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Do you have your headlights on the auto setting? You could have frost covering the light sensor and it turns on the light. Or in my case you go under an area or overpass where you have a lot of the sun blocked, the truck will turn them on and then weh you get more light turn them off. Check you switch to the left of center, this is the auto feature and then you pull out for the fogs.
Hope this helps.
Hope this helps.
Tuned
Joined: Oct 2004
Posts: 441
Likes: 6
From: Madison, WI
If it is just a momentary dimming, then goes away, I have this problem too. Not really a problem, but just a "thing." Let me explain, it has been on average about -30 below regular temp (not windchill) around here for the past couple weeks and I noticed when the AC kicks on (it automatically comes on with the defroster) that the compressor is so cold, that it is sticky and makes a large draw on the belt, which slows the alternator down, which causes the lights to dim.... Not really a defect, just cold temps. I've been freezing my bagettes off
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Junior User
Joined: Jan 2004
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From: iowa
mkoser, That sounds alot like it. My question is, I have the AC shut off when I use the defrost in cold temps. Will the crompressor kick in even with the AC light off ? This morning it wasn't as bad. It had warmed up to 0 degrees. The lights dimmed just barely a couple of times.
steve
steve
Tuned
Joined: Oct 2004
Posts: 441
Likes: 6
From: Madison, WI
Yes, the AC will kick on no matter what setting you have the AC in (on or off). When you turn on the Defroster, it automatically cycles the AC so it will help dry out your windows by blowing dry air across them.
Mine stops doing this after about 2 or three cycles. If yours keeps doing it, maybe you have a problem elsewhere. Maybe your alternator is bad, or you have a loose connection some where. If it gets worse, i would get it checked out under warranty.
MK
Mine stops doing this after about 2 or three cycles. If yours keeps doing it, maybe you have a problem elsewhere. Maybe your alternator is bad, or you have a loose connection some where. If it gets worse, i would get it checked out under warranty.
MK
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Joined: Aug 2004
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Wanted to bump this post up. Been having the same problems. This is not just cold weather related. Doesn't matter if the truck/weather is warm or cold. A/C or defroster on/off. Seems either like an intermittent ground or a problem with the volatage regulator or alternator. A couples times now it has lasted long enough to light low battery warning. Service department has no clue since it is intermittent. They plan on keeping it overnight to see what happens on cold start. Trying to tell them it happens while driving, leading more so to believe that there is a wire rubbing or a bad ground. Any thoughts....
Shawn
5.4 L
05 Crew XLT
Shawn
5.4 L
05 Crew XLT
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Junior User
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From: iowa
My problem ended up being a bad alternator. I took it in and everything checked fine, then they decided to put in a new alternator anyway. I did notice that it did make allot of noise. It was more noticeable actually when I noticed it was more quite with the new one. I think I read or heard from someone there were a few problems with a handfull of those alternators. I would get that checked first.
steve
steve
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From: Minnesota
Hey Guys,
I thought the AC only works automatically in defrost in temps above, say, 40F. I don't think you can dry out -15 to -30 air much more than it already is. Somebody correct me if I'm wrong. It certainly wouldn't be the first time.
I thought the AC only works automatically in defrost in temps above, say, 40F. I don't think you can dry out -15 to -30 air much more than it already is. Somebody correct me if I'm wrong. It certainly wouldn't be the first time.
