4x4 indicator light

[trailhead]

Finally getting around to some of the smaller stuff and this one has me stumped.  4x4 works, but the indicator light does not.  I’ve checked the switch on the CAD and it works.   When I run an instrument cluster check, no light.  Advice?

[Haggar]

if not working during test, the bulb is bad.

check there.

 

GL HTH

 

Hag

[dave110]

I was just about to say that. I agree with Haggar. Probably the bulb.

[trailhead]

Thank you.  I was trying to figure out which bulb and I ended up on mopar1973mans YouTube channel.  When I watch his video I don’t think the 4wd indicator lights up while doing the test.  All of my other lights do which leads me to believe the bulb is good.  Autozone just told me they couldn’t get that bulb so I’m hoping I can find one.   Anyway here is the video.  

 

[01_Cummins_4x4]

Depends upon the year of the truck to whether it has a bulb or LED light. My 01 has a LED 4wd light that won't come on when it's in 4wd mode. It is definitely going into 4x4 mode though.

 

I replaced the 4wd indicator switch, and depressed it fully while it was plugged into the wiring harness, but it still doesn't come on with the ignition in the run position. I'm down to chasing the 4wd light wiring for ground and sense wire continuity now.

Edited December 24, 2020 by 99_Cummins_4x4

[dripley]

9 hours ago, 99_Cummins_4x4 said:

Depends upon the year of the truck to whether it has a bulb or LED light. My 01 has a LED 4wd light that won't come on when it's in 4wd mode. It is definitely going into 4x4 mode though.

 

I replaced the 4wd indicator switch, and depressed it fully while it was plugged into the wiring harness, but it still doesn't come on with the ignition in the run position. I'm down to chasing the 4wd light wiring for ground and sense wire continuity now.

My 02 has incandescent bulbs, at least the ones I pulled long ago. I would like to put in LED's sometime in the future.

[Evan]

My 02 light only sometimes comes on. I always thought there was a switch or something it was tripping but not working or worn out.

 

Cad on 01.5?

 

As soon as you said light doesn't come on but 4wd works i assumed it was a non cad rig.

[01_Cummins_4x4]

My 01 Sport SLT has the CAD on the front axle. My 4x4 has always worked, but the LED "4WD" light in the instrument cluster didn't work. I finally dug out my multi meter and started tracing and verifying continuity in the wiring circuit. 

 

I had sense and ground circuit wire continuity on the 2 wire harness from the 4wd indicator light switch on the CAD to the 2 wire plugin at the engine harness connector. I found the #3 joint connector at the passenger side of the front end by the wheel well. I disconnected it and started checking continuity from the CAD harness connector to the #3 joint connector. I had continuity on the sense wiring but not on the ground wire. I clipped the ground wire a couple inches from the CAD wiring connector on the engine harness and found that the wire internally was broken. I soldered on a new piece of wire and heat shrunk it. Now my 4wd light on the dash comes right on. I figured the previous owner must have gotten a little to zealous with the ground wire at some time since the sheath was intact, but the interal copper strands were broken and not burnt.

Edited January 22, 2021 by 99_Cummins_4x4