No featured offers available
Learn more

No featured offers available

We feature offers with an Add to Cart button when an offer meets our high standards for:

  • Quality Price,
  • Reliable delivery option, and
  • Seller who offers good customer service
“No featured offers available” means no offers currently meet all of these expectations. Select See All Buying Options to shop available offers.
Select delivery location
See All Buying Options

LumaWerx H4/9003 Switching Ground Polarity Module

3.9 3.9 out of 5 stars 17 ratings

Product Description

Solution - A common problem found on many older Japanese vehicles: a switching ground opposed to traditional switching power for headlamp systems. While it is not a problem for incandescent and halogen lighting, when converting to LED, polarity matters. This module will retain the ground and mimic the functionality of a traditional switching power system. Designed - LumaWerx has designed and produced these ground switching modules to create a simple plug-and-play solution for most vehicles using an industry standard H4/9003 headlight plug with a switching ground when going from low to high beam. Installation - The LumaWerx H4/9003 polarity cancelers are designed to simply plug in-between the stock H4/9003 plug and allow your aftermarket LED lights to function properly while switching from high to low beam and low to high beam. To ensure proper functionality, we recommend installing one module on each side and installing at the same time as some cars and trust will not work properly without two modules installed together (one on each side). Note - Some cars and trucks have factory connections that are reversed on either side, we strongly recommend checking each circuit with a volt meter or test light to check for low beam power, high beam power and ground or in some cases: ground, ground and power as one side of the vehicle may be different than the other.

Product information

Technical Details

Additional Information

Warranty & Support

Amazon.com Return Policy:Amazon.com Voluntary 30-Day Return Guarantee: You can return many items you have purchased within 30 days following delivery of the item to you. Our Voluntary 30-Day Return Guarantee does not affect your legal right of withdrawal in any way. You can find out more about the exceptions and conditions here.

Feedback

LumaWerx

LumaWerx H4/9003 Switching Ground Polarity Module

Found a lower price? Let us know. Although we can't match every price reported, we'll use your feedback to ensure that our prices remain competitive.

Where did you see a lower price?
/
/
/
/
Please sign in to provide feedback.

Looking for specific info?

Customer reviews

3.9 out of 5 stars
3.9 out of 5
17 global ratings

Top reviews from the United States

Thomas M Ritter
5.0 out of 5 stars Made my 1983 FJ60 Land Cruiser's XPRITE LED headlight upgrade work!
Reviewed in the United States on October 3, 2021
Verified Purchase
This module was easy enough to install (It would be great if this thing had longer leads). It adapted the polarity of the Land Cruiser to the polarity that worked with the XPRITE headlights.

More detail: The Land Cruiser has one positive 12v wire and two wires connected to switches that complete the circuit to ground. The XPRITE headlights needed two switching positive wires, and one static ground wire. This module uses relays, not MOSFETs or other solid state circuitry ( just for extra information).
One person found this helpful
Helpful
 Report
Junior Diaz
3.0 out of 5 stars 50/50
Reviewed in the United States on September 4, 2023
Verified Purchase
Product came with no Wiring/Pinout diagram.

Fortunately I have Electrical experience and managed to figure correct pinout for harness being plugged in.

Worked great after pinout was figured. Ended in a super clean and satisfying install.

Definitely a problem solver for reverse polarity issues.
Helpful
 Report
Mike Lianza
5.0 out of 5 stars Awesome fix!
Reviewed in the United States on April 11, 2019
Verified Purchase
These worked perfectly on my 1986 Suzuki Carry. Without them, my LED lights would only work on High Beams. This looks to be really well built and it was easy to install and hide behind the light assembly. a+
One person found this helpful
Helpful
 Report
Milton Y.
1.0 out of 5 stars Did not work at all
Reviewed in the United States on March 9, 2021
Verified Purchase
The reverse polarity module did not work at all. Even when power is applied at one end, there is no output of any kind on the other end. One not working sure, but both were the same.
Helpful
 Report
Dirk S.
5.0 out of 5 stars Quick way to make LED headlights work on a classic car
Reviewed in the United States on March 17, 2024
My Datsun 510, like many cars of the era, has ground-switched headlights, meaning that the 12V lead is always hot to both the low and high beam, but the ground wire for each is only connected to ground on one or the other depending on what position the high beam lever is in. Works great for the high beams, but on the combination headlights this means the terminals that would normally get 12V get ground, and the shared ground wire for both is always at 12V.

Most LED headlights won’t work when you reverse the polarity like this.

Caused me a few head scratches when my new Holley Retrobright headlights didn’t work. I quickly realized I was either going to get working low beams or high beams by just switching pins around. Took me a while to know what to even search for until I found this little box and a few similar options from even more mysterious brands.

Sure, it would be cleaner to delete the old headlight relay near the firewall, rethink that setup, adjust wiring to the fuse box for that change, and then rewire from there to the headlights with a modern switched positive setup.

But, for 40 bucks (one box on each side) this is a very quick and easy temporary solution that may very well become permanent. The hardest part was finding good spots to zip-tie the boxes to.

How to: Connect the black wire to ground, basically any piece of metal on the car body (I wedged have each of them under a nut that hold the front blinkers in), plug the little box between your old connector and the new headlight and you’re good to go.

If you’re confused about the pin-out, look up what the pin-out for a standard H4 connector. Hard to mess up.
Helpful
 Report
derrick
5.0 out of 5 stars Awesome
Reviewed in the United States on January 1, 2020
Verified Purchase
Life saver of my own wiring. Plug and play working great.
One person found this helpful
Helpful
 Report
Amazon Customer
5.0 out of 5 stars Reverse polarity adapters.
Reviewed in the United States on March 18, 2020
Verified Purchase
Very nice. Easy to install. Great product.
One person found this helpful
Helpful
 Report
James S.
1.0 out of 5 stars Do not recomend
Reviewed in the United States on December 9, 2019
Verified Purchase
Did not work as advertised, intact after installing this as directed the headlights didn't work at all. I returned them.
Helpful
 Report