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Austin
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| Posted: Jun 06 2005 at 10:51am | IP Logged
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It works!
I've modified the wiring to the Diff Lock Control Unit - now my rear
e-locker will lock up in 2WD, 4HI and 4LO. I used a DPDT relay
and a lit rocker switch controlling the relay to switch both power and
ground.
When I flip my rocker switch in 2WD, 4HI or 4LO, I get a lit DIFF LOCK
light on the instrument cluster, and nothing else. So, I can have
a locked rear diff and keep ABLS to the front wheels.
I verified the diff is actually locked by putting the truck up on
jackstands, locking the rear diff in 2WD, shifting to Neutral and
spinning one rear tire - the other tire spins the same direction.
(An open differential would cause the tire to spin the opposite
direction.)
I also verified the diff is actually locked by playing in the
dirt. In 2WD with the diff locked, I lay down two beautiful marks
with no SLIP light. While turning, the inside rear tire slips -
it's obvious the diff is locked.
I'm still able to lock the rear diff in 4LO using the OEM switch.
I used a separate rocker switch (instead of using the OEM switch) and a
DPDT relay so that the installation wouldn't cause any malfunction
lamps, blinking no-worky lamps, or other unintended results.
Click here for the main thread on this.
First - a failed attempt:
I tried to simulate the transfer case in 4LO by grounding out the 4LO switch. Here's a bit of info about that:
The 4LO switch is a normally open switch, and it closes when the
transfer gear is under 4LO condition, detected by the L-H shift fork
position. The 4LO switch is located on the transfer case, just inside
of the front prop shaft flange. The 4LO switch inputs to the Transfer
Control Unit.
I jumped across the 4LO switch, and across the 4LO and the Wait
Detection Switch. All it'll do is confuse the Transfer Control Unit.
The problem is that the 4WD Shift Switch inputs to the Transfer Control
Unit, which then compares it to the various sensors on the transfer
case.
With the 4WD Shift Switch in 2WD or 4HI, when you jump the 4LO switch
(pin 24 to ground) you'll get a flashing 4LO light - indicating a
faulty 4LO switch or faulty wiring to the 4LO Switch.
With the 4WD Shift Switch in 2WD, when you jump the 4LO switch (pin 24
to ground) and the Wait Detection Switch (pin 17 to ground), the 4WD
Shift Indicator Lamp (the little drivetrain picture that tells you if
you're 2x4 or 4x4) will go out and the 4WD Warning Lamp (the lamp that
says 4WD) will flash.
The problem is that the 4WD Shift Switch inputs to the Transfer Control
Unit, which then compares it to the various sensors on the transfer
case. When the 4WD Shift Switch position isn't consistent with the
position sensors on the t-case, you get blinking lights and no-worky.
Having failed at tricking the control units into thinking conditions
are met to lock the rear diff, I bypassed the control units entirely –
I wired 12volt power directly to the diff lock solenoid.
Here a picture where all the stuff is:
Here are a couple wiring diagrams:
Here’s a pin explanation:
+12volts is applied on terminal 12, with terminal 11 being switched
ground – power to the diff solenoid is controlled by switching the
ground at terminal 11. I’m betting the diff control unit can
isolate the +12volts on terminal 12, so I wanted to switch both power
and ground.
Here's how I wired it:
The quick’n’dirty:
Cut the [Y] yellow wire at terminal 12 at the diff lock control unit harness.
Cut the [V] violet wire at terminal 11 at the diff lock control unit harness.
Strip insulation from black wire at terminal 3 at the diff lock control unit harness.
Strip insulation from [R/B] royal blue wire at terminal 1 at the diff lock control unit harness.
Connect DLCU side of yellow wire to relay terminal 1.
Connect jumper from royal blue wire (power) to relay terminal 3.
Connect diff lock solenoid side of yellow wire to relay terminal 5 (diff lock solenoid terminal 4).
Connect DLCU side of violet wire to relay terminal 2.
Connect jumper from black (ground) wire to relay terminal 4.
Connect solenoid side of violet wire to relay terminal 6 (diff lock solenoid terminal 2).
Connect jumper from royal blue wire (power) to hot side of rocker switch.
Connect jumper from black wire (ground) to other side of rocker switch.
Connect jumper from load terminal on rocker switch to relay terminal 7.
Connect jumper from relay terminal 8 to black wire (ground).
I'll post some pics of the install in a bit.
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Austin
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| Posted: Jun 06 2005 at 10:51am | IP Logged
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The Diff Lock Control Unit is positioned right between the two rear
seats - so, if you want access to it, you need to remove both rear
seats. There is no need to do this, though - there is an easier
place to do the wiring.
Here's the harness connector at the Diff Lock Control Unit. Note
the two blue wires on terminals 1 & 2 of the connector (upper
right). The manual labels them as color "R/B" which must mean
royal blue. Remember that blue color.
The best place to do the wiring is in the driver's kick panel.
There is only one wiring loom which runs to the rear of the
truck. There is also a nice place to house the relay - inside the
white plastic housing, right next to the little brown connector.
Good'n'protected.
Note the two smaller blue wires you can see in this photo - they are
not the ones you want to cut. If you see two colors of blue, go
with the darker blue. Royal blue vs. sky blue.
When you pull the tape off that loom, locate the yellow, violet, black
and royal blue wires. They're all a bit larger than most of the
other wires - 16 awg vs 18 awg. Separate them from the rest and
follow the wiring diagram in the first post above.
Here's the truck on jackstands to verify the diff is locked.
Okay, okay, so I got lazy... two jackstands and the jack under
the back pumpkin.
Here's where I mounted the lit rocker switch.
Anybody need more/different pictures?
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Austin
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| Posted: Jun 06 2005 at 10:53am | IP Logged
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The relay is Radio Shack p/n 275-218. DPTP relay,
12VDC/10A. The Diff Lock Control Unit is fused upstream by a 10A
fuse (as you saw in the first wiring diagram in the first post), so a
10A relay is large enough. I wanted a DPDT relay to maintain the
circuit in the original orientation when not in use, for two
reasons. 1, all the control units check all their switches and
sensors regularly, communicating via lan/can. If I'd isolated the
diff lock solenoid from the DLCU, there'd be a malfunction lamp.
2, both ground and power are routed through the DLCU, so I'm betting
it's able to isolate both, meaning I needed to supply both ground and
power for a complete circuit.
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Austin
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| Posted: Jun 06 2005 at 10:56am | IP Logged
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Here's a more complete wiring diagram:
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sonnytimes
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| Posted: Jun 12 2005 at 8:21pm | IP Logged
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Cool I was wondering when someone would try this. Let me know if or when the rearend eats itself. If it last awhile, I will do this. Looks like you have all bases covered.
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...and the daily beatings will continue untill moral inproves!
04 Crew Cab 4X4 Big Tow 05 Bed 05 Rearend
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Austin
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| Posted: Aug 11 2005 at 12:34am | IP Logged
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Still going strong. I use it almost weekly.
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E-Lock Locked in 2WD & 4HI & 4LO
Austin's Titan Page
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sonnytimes
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| Posted: Aug 14 2005 at 6:17pm | IP Logged
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I will start getting the parts together. Wish me luck.
__________________
...and the daily beatings will continue untill moral inproves!
04 Crew Cab 4X4 Big Tow 05 Bed 05 Rearend
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Nissan Titan Forums : Problems / Technical
Topic: E-Lock Locked in 2WD & 4HI & 4LO
