Rear locker mod? (1 Viewer)

[Ayune]

Just did this mod, but took a different approach. Instead of wiring the RDL relay's LO switch input (pin 8) to constant 12V, I disconnected that wire and routed the RDL switch input (pin 4) also into pin 8. The RDL switch now simultaneously tells the RDL relay that you're in LO and the switch is ON. In other words, both inputs go to 12V when the switch is turned to ON.

Here's the wiring diagram for 1998-2001 LCs showing the mod.

Here's how-to:

Unplug the RDL relay connector. It's the small black box behind the passenger footwell trim up against the firewall.

Using a pick slightly raise the pin retention tab on the connector (below left). You need to release wires 4 & 8 by moving the small plastic tabs within the connector (below center). Lift up the tabs with the pick while gently pulling on the wires and they'll slide right out.

I had some connector pins lying around from my radio upgrade, so I used one of those to jumper from pin 4 to pin 8. You can cut the black-with-blue-stripe wire and use its pin if you need to, just be sure to tape off the bare end of wire. Either way, tape off the black-with-blue-stripe wire.

Solder the second pin to the green-with-red-stripe wire (pin 4) and re-insert the spiced wires into pins 4 & 8. Done! Now your RDL can be actuated in any transfer case position.

EDIT: If you prefer to use a T-tap you would:
1 - Cut the black-with-red-stripe wire (pin 8) leaving enough length at the connector to go to a T-tap.
2 - Tape off the bare end of that wire in the wire harness.
3 - Connect that wire stub from pin 8 to the green-with-red-stripe wire (pin 4) using the T-tap.

 

[dale5740]

this looks great AYUNE! why is this a better approach? why was this better for you? thanks in advance!

 

[Ayune]

this looks great AYUNE! why is this a better approach? why was this better for you? thanks in advance!

Others have suggested messing with the speed sensor or Tcase position sensor but those effect other things like ABS and shift points. I thought I’d go right to to the source and simply trick the RDL ECU into locking the diff without any other ECUs knowing about it. It doesn’t require an additional switch or wiring or changing normal vehicle operation. It’s all taken care of at the RDL ECU connector.

 

[dale5740]

Others have suggested messing with the speed sensor or Tcase position sensor but those effect other things like ABS and shift points. I thought I’d go right to to the source and simply trick the RDL ECU into locking the diff without any other ECUs knowing about it. It doesn’t require an additional switch or wiring or changing normal vehicle operation. It’s all taken care of at the RDL ECU connector.

sounds like a winner to me!! thanks for taking the time to post and explain. I look forward to doing this mod asap

 

[Ayune]

Here’s the wire connector’s pin numbering for reference:

 

[Zooguy]

!!!Revived!!!
I've already done the pin 7 mod which allows me to engage the center diff lock in high or low gear at my convenience. By following @Ayune will that mess up the shift patterns in high and low gear and will it work using the black wire with a blue tracer if I've already disconnected that with the other modification?

 

[Ayune]

!!!Revived!!!
I've already done the pin 7 mod which allows me to engage the center diff lock in high or low gear at my convenience. By following @Ayune will that mess up the shift patterns in high and low gear and will it work using the black wire with a blue tracer if I've already disconnected that with the other modification?

This is a different box than the center diff Pin 7 mod. This change does not effect shift patterns, it just tricks the box to engaging the rear diff lock in either H or L.

 

[waller24]

What size t tap?

 

[waller24]

What si

Just did this mod, but took a different approach. Instead of wiring the RDL relay's LO switch input (pin 8) to constant 12V, I disconnected that wire and routed the RDL switch input (pin 4) also into pin 8. The RDL switch now simultaneously tells the RDL relay that you're in LO and the switch is ON. In other words, both inputs go to 12V when the switch is turned to ON.

Here's the wiring diagram for 1998-2001 LCs showing the mod.
View attachment 2178780

Here's how-to:

Unplug the RDL relay connector. It's the small black box behind the passenger footwell trim up against the firewall.

View attachment 2178788

Using a pick slightly raise the pin retention tab on the connector (below left). You need to release wires 4 & 8 by moving the small plastic tabs within the connector (below center). Lift up the tabs with the pick while gently pulling on the wires and they'll slide right out.

View attachment 2178762

I had some connector pins lying around from my radio upgrade, so I used one of those to jumper from pin 4 to pin 8. You can cut the black-with-blue-stripe wire and use its pin if you need to, just be sure to tape off the bare end of wire. Either way, tape off the black-with-blue-stripe wire.

View attachment 2178763

Solder the second pin to the green-with-red-stripe wire (pin 4) and re-insert the spiced wires into pins 4 & 8. Done! Now your RDL can be actuated in any transfer case position.

View attachment 2178764

EDIT: If you prefer to use a T-tap you would:
1 - Cut the black-with-red-stripe wire (pin 8) leaving enough length at the connector to go to a T-tap.
2 - Tape off the bare end of that wire in the wire harness.
3 - Connect that wire stub from pin 8 to the green-with-red-stripe wire (pin 4) using the T-tap.

What size t tap do you recommend?