# Turn Headlights On While Towing Rv !



## GoVols (Oct 7, 2005)

Leaving early am to go pick up the new camper and thought I would more closely look at the Chevy's owners manual. Found something I had not seen before.

The manual clearly says that if the camper has a 12V battery connected that I should turn on the headlights in order for the alternator to put out the appropriate voltage to keep the batteries up! Apparently the alternator doesn't go into a "boost" mode unless the headlights are on.

Don't know if this also goes for Ford, Dodge, etc., but it is certainly in the 2006 Chevrolet owners manual.


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## 7heaven (Jun 4, 2005)

Strange, you would think it would sense the draw from the TT...









Better check my manual, but Ford probably doesn't have that design flaw...


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## Crawfish (Sep 14, 2005)

I did not know that.







Makes sense though.







Thanks for the tip justlookin.

Leon


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## tdvffjohn (Mar 10, 2005)

I will need to look at mine but that makes no sence. The regulator senses load and recharges the battery. That means if I put any amplifiers for my stereo or extra driving lights that my battery will run down if the headlights are not turned on????

On a side note, I always pull any trailer with my parking lights on so I can see in my mirrors that the trailer is lit up. If it is not, that means my light plug came out and I have no trailer brakes.

John


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## HootBob (Apr 26, 2004)

I don't know but I always have my lights on when towing the TT
The more lights that are on the better chance of someone noticing you
Better to play it safe then sorry

Don


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## 7heaven (Jun 4, 2005)

Don, That's a good safety tip. When we lived in the Czech Republic, it was the law to have your headlights on during the "standard time" months (Fall/Winter).


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## Fire44 (Mar 6, 2005)

I learned something new today!! Did not know that. From the GM owners manual:

(2006 models)

"If you are charging a remote (non-vehicle) battery, turn on the headlamps to boost the vehicle system voltage and properly charge the battery."

Page 4-91 of the owners manual

Gary


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## nascarcamper (Jan 27, 2005)

Fire44 said:


> I learned something new today!! Did not know that. From the GM owners manual:
> 
> (2006 models)
> 
> ...


Is that under the jump starting section? It's common practice to turn on the headlights of the vehicle giving the boost so when the boosted vehicle starts the headlights act as a surge protector.


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## GoVols (Oct 7, 2005)

nascarcamper said:


> Fire44 said:
> 
> 
> > I learned something new today!!Â Did not know that.Â From the GM owners manual:
> ...


I was reading in the "Towing A Trailer" section of the Chevy's manual.

I'm with John, it makes absolutely no sense, but I read it, and read it again. Yep, that's what it says!


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## nascarcamper (Jan 27, 2005)

justlookin said:


> nascarcamper said:
> 
> 
> > Fire44 said:
> ...


That's pretty strange. I've never heard of such a thing.


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## Ghosty (Jan 17, 2005)

Makes no sense since the regulator by its very design would sense a voltage draw and kick in...

oh well -- i run the headlights always anyway...


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## Katrina (Dec 16, 2004)

Ghosty said:


> Makes no sense since the regulator by its very design would sense a voltage draw and kick in...
> 
> oh well -- i run the headlights always anyway...
> [snapback]96110[/snapback]​


thats the way regulators always worked before, but with the computers on todays trucks, who knows.

I can see how it can be done on the newer trucks, just not sure why.

I do know for sure that the headlight circuit is computer controlled and switching them on has an effect on other things in the truck.
So it is possible that turning on the headlights could very well tell the alternator to change it's output.

I'll check mine tomorrow with a good meter and see if I can tell anything.


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## 2500Ram (Oct 30, 2005)

Ghosty said:


> oh well -- i run the headlights always anyway...
> [snapback]96110[/snapback]​


Agree and do the same. If the running lights are on I know I have trailer brakes.

Bill.


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## Oregon_Camper (Sep 13, 2004)

Nice tip...

Mine is always in the "auto" mode...wonder if it is smart enough to know the rear plug is attached and then "auto"mactically turn on the lights?

Will have to test this out.


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## nascarcamper (Jan 27, 2005)

That's one of my favorite things on the Superduty. It lets you know if you're connected.


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## hatcityhosehauler (Feb 13, 2004)

That's got to be something with the newer ones, cause my '02 didn't say that. I know, cause like justlookin, I read everything I could find in the manual about towing. Like everyone else, I usually have the running lights on during the day while towing, but I don't understand way the voltage regulator wouldn't sense the draw, and boost the output of the alternator.

Tim


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## NDJollyMon (Aug 22, 2003)

The Police told me:
By driving with your headlights on...
you are 30% less likely to get into an accident.

Great safety tip HootBob.


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## LarryTheOutback (Jun 15, 2005)

NDJollyMon said:


> By driving with your headlights on...
> you are 30% less likely to get into an accident.[snapback]96176[/snapback]​


This is why so many new vehicles have Daytime Running Lights. On some cars these are the headlights, on others (like my Burb) they are separate bright white lights that are on during the day.

Our friends in Canada have been far, far ahead of us in this area.

Ed


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## Thor (Apr 7, 2004)

In Canada all cars & trucks have to have daytime running lights. This means the headlights are always on







You cannot turn them off unless you are in park and/or with the emergency brake on.

Thor


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## Grunt0311 (Aug 23, 2005)

Thor said:


> In Canada all cars & trucks have to have daytime running lights. This means the headlights are always on
> 
> 
> 
> ...


Or pull the fuse


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## Fire44 (Mar 6, 2005)

OK.....I got an answer!!!!

The 2005 and newer have a device to prevent overcharging of the battery. The device tells the computer when the battery is fully charged, the computer then reduces the output of the alternator, reducing the risk of overcharging the battery and in theory the alternator isn't as hard to spin...so it improves gas mileage. The overcharge device only monitors the vehicle battery/batteries not the hot wire going to the trailer. By turning on the headlights the computer keeps the alternator working at the higher rate (over 12.2 volts) allowing charging of the trailer battery.

The 2004 and older GM trucks do not have the overcharge device, so turning on the headlamps is not required.

Gary


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## tdvffjohn (Mar 10, 2005)

Thanks Gary, they certainly do not build them using the K.I.S.S. method anymore.









John


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## nascarcamper (Jan 27, 2005)

Way to go Gary.


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## hatcityhosehauler (Feb 13, 2004)

Jeeze....and they said Ford had the "better Idea" You'd think they would have thought of designing a monitor for the battery feed going to the trailer connection.

Tim


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## Oregon_Camper (Sep 13, 2004)

Fire44 said:


> OK.....I got an answer!!!!
> 
> The 2005 and newer have a device to prevent overcharging of the battery. The device tells the computer when the battery is fully charged, the computer then reduces the output of the alternator, reducing the risk of overcharging the battery and in theory the alternator isn't as hard to spin...so it improves gas mileage. The overcharge device only monitors the vehicle battery/batteries not the hot wire going to the trailer. By turning on the headlights the computer keeps the alternator working at the higher rate (over 12.2 volts) allowing charging of the trailer battery.
> 
> ...


RATS!!! Guess I'll just have to turn on the lights in my OLD 2004 Suburban.


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## PDX_Doug (Nov 16, 2004)

Interesting tip. Like Hoot Bob, I always tow with the lights on anyway, but still good to know.

Happy Trails,
Doug


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## Camping Fan (Dec 18, 2005)

nascarcamper said:


> That's one of my favorite things on the Superduty. It lets you know if you're connected.
> 
> 
> 
> ...


One of the advantages of the Prodigy brake controller is that it also lets' you know if you're connected or not.


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