RR Diff Lock light on

[Jetmx]

The RR Diff Lock light is on with the switch is out (normal position). I have a 1999 4runner limited 4x4. It's kind of a weird situation as I'll explain.

First of all what does RR stand for?

I read the Owners manual & assume that the vehicle is always in the single axle operating mode until I push this button while in L4. Then it goes into dual axle drive while in L4 drive.

I first noticed the light on intermittently. Then all my instrument panel lights went out, & are still out. I'm thinking they may be related- maybe not. The RR light is on constantly right now.

I would assume this light tells me that the rear end is being driven by both axles. So, I also assume that there is a switch on the rear end to indicate that. I dont have a wiring diagram to look at that. Could anyone PM a wiring diagram related to the RR light & interior instrument panel lights.

Any thoughs, suggestions & comments are welcomed. Thanks ahead.

[dandeman]

Interesting...I'm looking at the factory service manual and the 2 "RR"s acronym is not spelled out, but it definitely is the switch to lock the rear differential.

The L4 button puts the vehicle in 4wd mode; if the diff lock switch is on and, vehicle speed is less than 5mph, the rear axle will lock both axles together.

Regarding the instrument lights being out, check the 10A Gauge Fuse. That fuse not only feeds the instrument lights, but also feeds the rear diff lock control switch, so with the fuse blown there may be some current attempting to feed back from the Diff Lock ECU back into the instrument lights.. So, recommend you get your instrument lights working and then see if you still have a problem with the diff lock light.

You are correct there is a switch on the rear diff lock motor that confirms the rear axle diff is locked.

[Tech1984]

In Toyota lingo RR means rear. FR means front. It's common for diff lock actuators to become stuck from lack of use. Sometimes some light tapping on the actuator frees them up.
Sure sounds like you have some other issues though.

[Jetmx]

Thanks everyone for the info. I will check the fuse for the instruments first & go from there.

[Jetmx]

Checked the 10amp fuse under the hood & it was zapped. Changed it & the instrument lights work now. Looked at the RR Diff. Lock light again. Now I dont think it was a problem at all! What I found is that during the day &/or when light is shining on the switch it is easily readable like it is backlit. But when I checked it at night when it was completely dark , I could not see any display. So my take on it is that's how it's supposed to be.

[jetwhine]

Jetmx,

If the lights are out that is a good thing. No lights no problems.