Piston Slap: JK-ing Around With LED Headlight Upgrades? (PART II)

Sajeev writes:

Apparently the ears of noted lighting consultant Daniel Stern begin to burn whenever Piston Slap discusses lighting upgrades. While I gave an analysis of the current LED-landscape to the best of my knowledge, I am honored to publish his insights on Jeep JK headlight upgrades.

And those of us with old-school halogen reflectors get a little feedback, too. Stick around for that.

Daniel Stern answers:

Like their predecessor “HID kits,” today’s “LED bulb conversions” now flooding the market are not a legitimate, effective, safe, or legal product. No matter whose name is on them, these are not capable of producing light in the right pattern for the lamp’s optics to work; you get a random spray of unfocused light instead of a beam pattern.

But there’s a number of engineered LED headlamps on the market — they range in quality and performance from pathetic to excellent. The 701C from Peterson (in Peterson or Sylvania Zevo packaging — same lamp) is good. The Truck-Lite unit is good, but the king daddy of them all is the 8700 Evolution-J from JW Speaker: these units are plug-and-play in the JK (’07+) Wranglers. With any of the other LED headlamps worth considering you will need anti-flicker/adapters pigtails.

None of the LED headlamps linked here is an advisable choice if you do a lot of wintertime driving with heavy snow and slush; the LED headlamp lenses run cold so snow and ice can build up on them instead of melting off like they do from a warm halogen or BiXenon lamp lens. There is a heated-lens versions of the Truck-Lite lamp and there’s now a heated-lens version of the JW Speaker lamp as well. No heated-lens version of the JK-specific Evo-J lamps, and you’ll need those anti-flicker/adapter pigtails.

There’s also the factory-optional LED headlamp assemblies, but it’s tough to see them as cost-effective: they’re very expensive, their performance isn’t better than the lamps listed above, and they have no lens heater.

About Lamp Aim:

Lamp aim is by far the main thing that determines how well you can (or can’t) see at night with any given set of lamps, so this is crucial: you will need to see to it that the lamps are aimed carefully and correctly with an optical aiming machine per the “VOL” instructions here (unless you install the Peterson or Truck-Lite LEDs, then the correct setting is “VOR”). It can be difficult to find a shop that has (and uses) an optical aiming machine; keep calling around until you get the right answer. “We shine them on a wall/on a screen” is the wrong answer. To get an idea of what a proper lamp aim job looks like, see this VW document.

US/Canada-market JK Wranglers do not have a provision for adjustment of the horizontal (left/right) aim of the headlamps, only for the vertical (up/down). At least in theory this is fine; the horizontal aim is fixed at straight ahead, which is correct.

However, some individuals may need or want to alter the horizontal aim. To add horizontal aim adjustability, you will need two Mopar part number 5507 8114AA (Screw, headlamp horizontal) which should cost only around $5 from any Chrysler/Dodge/Jeep/Ram dealer. To install them, remove the grille and headlight assembly. Carefully remove the black headlamp mount ring/bucket by pulling straight out. Unscrew the pivot stud, thread in the new adjustment screw, push the ring back on, and put the light back in. Then you will have to carefully aim the headlamps not only vertically but also horizontally, keeping in mind headlamp aim is not subject to opinions or preferences; there really is a correct setting for a given kind of headlamp at a given mount height.

If your JK has the daytime running light function enabled (mandatorily in Canada, optionally in the States), and you’re installing anything other than the JW Speaker Evo-J lamps, you will need to rework the daytime running light function to move it off the headlamps — a dealer service department must de-activate the DRLs with their diagnostic computer interface, or you can do it yourself with a device called a ProCal. If you don’t do this one way or the other, the DRLs will operate in an unsafe and illegal manner until the LEDs cook to death (and they will). Why? Because the DRL function runs the headlamps at reduced voltage. This is not safely compatible with LED headlamps that haven’t been specifically designed for it.

Daytime running lights *do* significantly reduce your risk of being in a crash during the daytime, and are required equipment in Canada, throughout Europe, and in a large and growing number of other countries throughout the world because they are a very cost-effective safety device (i.e., they work). The ProCal dingus lets you move the DRL function to the front turn signals, or if you don’t wish to buy a $200 widget you won’t use much, you can add turn signal DRLs, which comply with US and Canadian Motor Vehicle Safety Standards and are approved in all states, provinces, and territories, with a standalone module.

(This is where Sajeev asked Daniel about future LED replacements for the OG 9004 bulb in his beloved 1980s Aero-Fords, like this Mark VII GTC Stage I)

[That is] Overwhelmingly unlikely to ever happen.

We’re starting to begin to approach getting close on the single-axial-filament types (9005, 9006, H7, H11…), and there’s some promise on the dual-axial-filament types (H4, 9007, H13…) but it is effectively impossible to do it with twin transverse filaments (9004). That’s because the low beam filament is both aft and above the high beam filament. You could make a board with its flat surfaces facing up and down, with its LED emitters in transverse rows one ahead of the other, but that wouldn’t address the “above” aspect.

[Image: Shutterstock user Oleksiy Mark,© 2018 Sajeev Mehta/The Truth About Cars]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.