Adding parking light functionality to ZJ front turn signals.
By Scott Mueller firstname.lastname@example.org
Ever since I first bought a Grand Cherokee in 1996 it always bothered me that when you look at any ZJ with the headlights on, it looks as if the parking lamp bulbs in the front turn signals are burned out. Of course they designed it that way, that is the front turn signals are only turn signals, while in most other vehicles the front turn signals also serve as parking lights. Even though it was designed that way, it still doesn’t look right. After trading in the ’96 Orvis on a ’98 5.9 Limited, I decided I would correct this problem. The fix is simple: I replaced the single filament (2-wire) sockets with dual filament (3-wire) sockets, and attached the extra wire to the parking light circuit.
All this was fairly easy since the front turn signal, parking and side marker lights are on a separate auxiliary harness about 2 feet long which unplugs from the main under-hood harness. I simply removed the front turn/park/side marker harnesses and did all the modification work on the bench, then reinstalled them as before. No changes are made to the main vehicle harness or to the turn signal housing, only the auxiliary harnesses are altered. If anybody were to see it they would swear it came from Chrysler this way, it is a 100% factory appearing installation.
Note that the color codes and socket types are different for ’93-’96 and ’97-’98 ZJs. It is strange but true that in ’97 (NOT in ’96 as you would think) Jeep changed the ZJ turn signals from an S8 (Straight side,
8-eighths of an inch in diameter) 15mm Bayonet Candelabra base type bulb to an S8 Wedge base bulb. Specifically the ’93-’96 ZJs used a trade number 1295NA (Natural Amber) bulb, which is the brightest (38cp) and most powerful amber colored single filament S8 bayonet base bulb on the market, and the ’97-’98 ZJs used a 3454NAK (Natural Amber, Krypton filled) dual filament S8 wedge base bulb. A friend of mine at Sylvania actually *designed* the 3454NAK for Chrysler, and it is the brightest and most powerful amber colored dual filament S8 wedge bulb in existence (38/2.2 cp major/minor).
What is even more interesting is that the 3454 used in ’97 and ’98 is a *dual filament* bulb, even though the ZJ only has a single filament socket! Unlike the 15mm bayonet based bulbs, which use a different base and socket for dual vs. single filament types, all S8 wedge based bulbs (whether single or dual filament) use the same base and socket. Since the base is the same for S8 wedge type bulbs whether they are single or dual filament, my friend at Sylvania decided to include the minor filament in the bulb even though it was specifically being created under a contract bid for the ’97-’98 ZJ (Sylvania was the supplier), and only the major filament would ever be used in that application.
He decided to add the minor filament so the bulb could be used not only in the single filament application for which it was designed, but also in possible future dual filament applications. The sad thing is that no other manufacturer ever did use it and in fact the bulb was recently discontinued (you can still get them from Chrysler inventory but not from Sylvania). The “454” designation was also my friend’s idea (the designing engineer usually gets to select the trade designation for a new bulb), because in his mind this was the “big block” of signal bulbs, being more powerful (brighter) than all the rest. I told him he should have called it the 3426 or 3440 instead, but he is a GM man and doesn’t speak Mopar.
The ’96 and earlier ZJs use a 1295NA (natural amber) single filament bulb. This is a Bay15s (bayonet 15mm single contact base) S8 amber bulb, which is also the brightest available in the 15mm bayonet candelabra base. It is in fact the same brightness as the wedge base 3454NAK (38cp), but unfortunately it only has a single filament. Also unfortunately there are no dual filament Bay15 base amber bulbs that are equally as bright, but there is something close. The next closest would be the 2357NAK (Natural Amber glass, Krypton filled) or 2357AK (Amber coated glass, Krypton filled) which are both rated 30/2.2 cp major/minor. If you are converting a ’93 to ’96 ZJ to dual filament turn signal sockets, then you would want to change the socket to a dual filament index base type, and install one of the 2357A bulbs I listed above.
For the ’97-’98 which uses the 3454NAK, all you need to do is change the turn signal sockets to dual filament types, and the dormant minor filament already present in your stock 3454NAK bulbs will then illuminate. Unfortunately the socket mounting tabs are unique on the ZJ front turn signals and sockets with those unique tabs are not available separately in a dual filament version. Fortunately I found a compatible socket that can be purchased, disassembled and used for parts to essentially “remanufacture” the stock sockets as dual filament types.
To do this I purchased 2 of p/n 04636359 ($9.45 list ea., about $7.09 net ea.) which are dual filament socket pigtails, and with the same bulb positional depth. Sockets are available in several depths, you need the 1.00″ depth version listed above or the bulb will not be positioned at the focal point of the reflector. Then I disassembled both the stock front sockets and the new sockets I bought (this can be tricky, but I devised a method that works flawlessly and does not damage the socket), and used the needed extra parts from the new sockets to rebuild the stock sockets as 3-wire types. This involved removing two bulb contacts, one additional wire with terminal and the three wire silicone seal from the new socket and installing them into the existing stock socket. This essentially remakes the stock 2-wire socket into a dual filament 3-wire socket.
To proceed, first remove the headlights, side markers and turn signals from the ZJ, and then disconnect the front turn signal harnesses. Then you can work on these harnesses on a bench away from the vehicle.
For ’97-’98 ZJs only:
The stock 2-wire sockets where the turn signal bulbs are mounted will have to be disassembled and reassembled with parts from the new 3-wire sockets you purchased.
To disassemble these sockets:
-Loosely clamp the socket by the edges in a vise with the bulb facing up,and remove the bulb.
-Obtain a very small and thin flat blade screwdriver, and wedge it between the base and the cylindrical bulb holding insert portion.
-Use a small hammer to tap the screwdriver all the way down between the cylindrical portion and the base. This will break the glue bond between them.
-Repeat this in at least 4 positions around the sides of the cylindrical portion. Eventually the entire glue bond between the cylindrical portion and the base should be broken, and you should be able to grab the cylindrical part and pull it out.
-Remove the wire seal, lift up the bulb contact portion and pull it out, then extract the wires with terminals from the socket. You will have to use the small screwdriver to bend the terminals slightly as there is a tang that helps to lock them in place. Set all of the socket parts aside for now.
-Repeat the socket disassembly procedure for the other original socket as well as both of the new sockets you purchased. Use the small screwdriver to scrape off any glue residue to prepare the surfaces for re-gluing.
-Reassemble the original sockets using the internal parts and silicone seals from the new sockets, adding the extra (third) terminal wire for the minor filament. You’ll see how this works and how they go back together once you actually do it.
-When reassembled, the original sockets should have 4 metal contact tabs visible to touch the contacts on the bulb, and an extra wire coming out for the minor filament.
-Once you are sure the socket assemblies are correct, then take them apart and reassemble for a final time adding some cyanoacrylate glue (Super Glue, Krazy Glue, Loctite QuickTite, SuperBonder, etc.) around the base components. You’ll see where the parts were originally glued, I’d recommend placing glue in these same positions.
-With the socket reassembled it looks and functions exactly as if the socket came that way from the factory. Then splice the new 3rd wire to the running light circuit (blue/red wire) from the park light.
For ’93-’96 ZJs only:
You’ll have to get a compatible dual filament bayonet index base that has the correct mating ears for the turn signal housing from a parts store and then simply cut the existing socket off, and splice the new one on. Then install new 2357AK bulbs (currently the brightest bayonet base amber dual filament bulbs) and your turn signals will now light as they should have from the beginning.
Note: The factory seals all splices with adhesive lined heat shrink tubing, which is exactly what I recommend. You can get this at any good electronics supply store. Then rewrap the harness using harness wrap tape. This was all fairly easy to do on a bench since the front turn signal harness is about two feet long and be easily unplugged and completely removed from the vehicle. I merely unwrapped the harness tape, found the blue/red wire, spliced (and soldered) the new wire into that circuit (using adhesive lined weatherproof heat shrink tubing to seal it watertight just like the factory uses). Then I re-taped the harness and installed it back into the vehicle using all the stock clips and routing. If anybody were to see it they would swear it came from Chrysler this way, it is a 100% “factory engineered” installation.
I really like the additional park lights on my ZJ, they really complete the front end look with the lights on. To add to the appearance up front I also installed brighter W5yW (5W amber wedge bulbs) in place of the stock 3-watt 194NA bulbs in both the existing side park light and front side markers (you can get these from a Mercedes dealer under Mercedes part number 002-544-26-94 for $3.54 each). 4 bulbs are required, two on each side.
A note on the 3454NAK bulbs:
Unfortunately the 3454NAK bulb found no other OEM vehicle applications since Sylvania introduced it in ’97. Because of the limited OEM use of the bulb (only Chrysler ever used it and only in the ’97-’98 Grand Cherokee), no other bulb manufacturers (i.e. GE, Wagner) ever made them, and in fact my friend at Sylvania just told me Sylvania recently discontinued it due to lack of sales. I can still get them from Chrysler (who has an inventory of them) at about $2.50 a pop under p/n 154862AA. I bought 10 of them recently just in case Chrysler stock runs out. I’m not worried that I’ll burn out that many turn signals in my GC, but since the 3454NAK can serve as a brighter replacement for any amber 3057A/NA, 3156A/NA, 3157A/NA, 3357A/NA, or 3457A/NA bulbs, I’d like to have a few around for future vehicle upgrades.
TS01.jpg – ZJ front left w/lights off.
TS02.jpg, TS04.jpg – ZJ front left w/park lights on (after modification).
Note turn signal portion is illuminated.
TS03.jpg, TS05.jpg – ZJ front left w/turn signal on. Note lower left side marker light is off in this picture, as it flashes off as the turn signal flashes on (standard function).
TS06.jpg – Stock front park/turn signal harness, note the 2-wire grey socket on the left, which will be disassembled and rebuilt into a 3-wire socket (adding a wire for the minor filament) using internal parts from the new 3-wire socket.
TS07.jpg – New 3-wire socket with 1.00″ deep center section. This will be disassembled and the internal components used to rebuild the 2-wire socket in the part/turn signal harness into a 3-wire socket.
TS08.jpg – Disassembled 3-wire socket showing all of the individual components. From the upper left going clockwise the parts include the inner metal terminals and support, cylindrical bulb support, socket base,
socket seal, wire seal, and three wires with terminals attached.