Positive/Negative switched headlights

[RangerPilot]

I was talking to a buddy about cop cars earlier and how they have the headlights that pulse from side to side. He said they can do this on positive switched headlights (where the 12V is applied/removed/applied/etc), but not negative switched headlights (where 12V is always present, but the ground is cycled). I told him that didn't make sense 'cause you could pulse it either way. Correct?

On that note, is a '98 Explorer positive or negative switched? What about the parking lights? And same questions about an '02 F-250.

Thanks.

 

[Brian_B]

I believe they use what is called a wigwag to do the lights like that. I know nothing about grounds or anything.

 

[surewhynot]

The explorer is positive switched, negative grounded.

 

[smokey]

Brian your on as usual they use a wig wag circuit

 

[RangerPilot]

The explorer is positive switched, negative grounded.

So the ground is always there, and the 12V is just controlled (like a stereo amp)?

Brian_B or smokey...what's a "wig wag" and how does it work? Just pulse the 12V to the headlights?

 

[Brian_B]

Here is what wiki says about them:

http://en.wikipedia.org/wiki/Wig-wag_(automobile)

Aaron could probably be more helpful with where to get them and all that. I think you have to be fire dept or police to buy them.

There is proably a way to build one from your local radio shack, but I know nothing about electronics.

 

[surewhynot]

Yup Zach, the ground is always there. The 12+ is switched.

 

[Truckin4life]

You can get them off of ebay... I got 2 sets. The problem is that fords have each headlight with a power wire instead of one wire running the two.... So you have to get creative and install a relay to get the ebay versions to work, but ive got them on my truck, they work and do there job well actually....

Ive got them to flash wig wag the high beams on and off, if the lights are on you can still see the wig wag...

 

[dragogt]

So the ground is always there, and the 12V is just controlled (like a stereo amp)?

Brian_B or smokey...what's a "wig wag" and how does it work? Just pulse the 12V to the headlights?

http://www.swps.com/whelheadflas.html ... http://www.swps.com/headtailflas.html

 

[RangerPilot]

Oh that's pretty cool, thanks for all the info and links guys, turns out I was right and he was wrong. lol