Jeep Grand Cherokee ZJ Turn Signal to DRL Mod with LED Switchbacks

Jeep Grand Cherokee ZJ Turn Signal to DRL Mod Image 1

Last Updated on January 10, 2020

I recently modded the 1997 Jeep Grand Cherokee front turn signals to be on with the side signals like DRLs. I accomplished this by using male bulb pigtails plugged into the factory wire harness and wired them to new female bulb pigtails that would plug into the light housings. Doing this I was able to convert the front bulbs to 1157 style from 1156 style, stole the extra required wire from the blue/red wire on the side signals (also by using male bulb pigtails that plugged into the factory harness that was wired to a new female bulb housing – no harness was cut at and this mod can be easily undone.)

I also replaced the stock flasher with a Novita ep27 LED flasher, I tried a Luyed brand ep27 and it didn’t work when Jeep was running.

Once that was all done put in some Amber-Off style LED Switchbacks. No hyper flash, everything works, and I didn’t ruin my factory wiring harness. 😀

**NOTE:: Check your current front lower blinker sockets before ordering, especially if you have a 1997 Grand Cherokee. My ZJ is 1997 and it must be an early production example becuase it still has the 93-96 lower front blinker style bulbs that are 1156 bayonets instead of the 3157 blade style bulbs that 97-98 should have.

Jeep Grand Cherokee ZJ Turn Signal to DRL Mod Parts List:

Pigtails and Sockets:

93-98 Grand Cherokees

Male Pigtail for Side sockets: – T10 Male Pigtail (93-98)
Female Pigtail for Side sockets – T10 Female Socket Pigtail (93-98)

93-96 Grand Cherokees

Male Pigtails for Front sockets: – 1156 Male Pigtail (93-96)
Female Pigtail for Front sockets: – 1157 Female Socket Pigtail

97-98 Grand Cherokees

Male Pigtails for Front sockets: – 3157 Male Pigtail (97-98, should be 3156 but they don’t sell those so use these and ignore blue wire)
Female Pigtail for Front sockets: – 3157 Female Socket Pigtail (97-98)

LED Flasher and Bulbs

NOTE: You could Skip all of the below parts if not converting to LED and are only wanting to mod the front signal to be on as a Parking/Running light with a regular incandescent dual-filament bulb.

LED Flasher Relay: – Novita EP27 (Luyed EP27 did NOT work)

93-96 Grand Cherokees

LED Switchbacks for Front signal: – Your choice of any 1157 style switchbacks, but I suggest a pair with good reviews and make sure they are the Amber-Off type that are White when signal is off and Amber blinking when signal is on. The other type Amber-White will alternate Amber and White when signal is on or even just keep White solid while Amber blinks – and either way they are terrible.

97-98 Grand Cherokees

LED Switchbacks for Front signal: – Get 3157 style switchbacks if you have the 97-98 blade style bulbs, obviously.

Optional Parts

OPTIONAL LED Non-Switchbacks for Front signal: – Regular dual-filament 1157 style Amber bulbs would work as well if you don’t prefer Switchbacks and want the “Stock” Look. (Again, get 3157 style if you are sticking with that socket style)

OPTIONAL Amber LED for Lower Side signal: – Regular T10 Amber LEDs, could get any you prefer.

SUPER OPTIONAL LED for Corner light:
May as well upgrade that while you have it out.
For Amber, just use the same bulbs used for the Lower Side signal above.
For White, any of these would do –

Jeep Grand Cherokee ZJ Turn Signal to DRL Mod Instructions:

  1. Disconnect negative battery terminal to not shock yourself or blow fuses/relays while working.
  2. Plug your Male pigtail connectors into the stock bulb sockets on the harness. When doing the T10 side signal, make sure the red wire on the male pigtail is on the side of the stock harness with Blue/Red wire.
  3. Wire the Male pigtails to the Female pigtails and steal the blue/red wire from the Side Signal and use it for the extra third wire needed for the new Front Signal Socket.
  4. Using the exact parts I linked to, this is the exact process:
    1. 1156 Male pigtail Red wire to the 1157 Female Socket Pigtail White Wire.
    2. 1156 Male pigtail Black wire to ONE of the 1157 Female Socket Black wires.
    3. T10 Male pigtail Black wire to T10 Female Socket Black wire.
    4. T10 Male pigtail Red wire to T10 Female Socket Red wire AND the SECOND black wire of the 1157 Female Socket.
    5. Insert all of your bulbs for testing. With Jeep turned off, key forward to the On position, make sure to test Left/Right signals and hazards with lights off, again with parking lights on, and again with headlights on. Then start the jeep and repeat the same tests.

Jeep Grand Cherokee ZJ Turn Signal to DRL Mod Image 1

(Same basic process would be used with the 3156/3157 blade style sockets on most 97-98 ZJs as well, except the extra blue wire on the Male 3157 pigtail that plugs into the Front Signal Harness would be ignored.)

Instruction Note 1: I suggest using your stock flasher for testing, it will work but just hyperflash – however, if you screwed up wiring you might fry it and I’d rather fry the stock flasher than the new LED flasher just purchased. The choice is yours.

Instruction Note 2: If using LED switchbacks and they are working in reverse (amber lights are used for parking lights and white is used for signals) – switch the TWO black wires on the 1157 Female Socket in steps B and D. Same goes if you’re not using switchbacks but your parking lights seem brighter than your signals flashing – the parking lights should be dim and the signals bright.

Instruction Note 3: If your T10 LED Side signal only comes on for parking lights but doesn’t blink for signal, or it blinks for signal but doesn’t come on for parking light – take the bulb out and rotate it 180 degrees and it should work correctly. LED lights are single polarity and only work one way, unlike incandescent bulbs, and they act wonky if reversely plugged in.

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