CDL help!

Joined
Mar 14, 2019
Messages
40
Location
Maryland
Hey Mud community first off let me start of by saying I have spent a considerable amount of time combing the forums and haven't found the answers I'm looking for.

98 LC with the center and rear locker, pin-7 mod has been done

ever since I purchased the truck the cdl has not engaged, I have 0 change when driving slowly in figure 8 patterns or reversing. done all the little tricks trying to get it to "free it up" the CDL.

now what I do know is when pressing the button I do hear the relay activating but nothing under the truck and the fuses are good.
I also have NO indicator light on the dash when I press the button or when the key is just switched on, I pulled the cluster last night and switched the bulb with the rear locker bulb (which does illuminate when the key is on or the rear is locked ) and still nothing when key first turns on. So I have eliminated a burnt out bulb.

I have a new CDL switch for the transfer case coming in today which hopefully will solve the light issue

I guess my rear question is.... if the CDL switch on the transfer case is bad would it cause the actuator not to function??? or am I looking at pulling the actuator to free it and/or replace it

What should I check next? thanks MUD thank you all for your time

LC1.jpg
 

Ayune

SILVER Star
Joined
Feb 12, 2017
Messages
1,350
Location
Portland, OR
Hey there, I have basically the same truck.

Since there is no difference in driving when the CDL button is pushed in, your CDL is not engaging.

Relay clicking under the dash is a sign that the wiring is good between the switch and control box.

The CDL detector switch is pushed only when the CDL engages, and that illuminates your dash light. So replacing the detector switch won't likely fix it, but it's not a bad idea to change it anyways. :)

The CDL dash light does not come on briefly when the car is started. The RDL light does because it is controlled by an ECU, but the CDL light is simply wired directly to the detector switch.

So the possibilities are:

1. The CDL mechanism isn't getting power. Check the wiring harness for damage, and/or probe the connector to see power is present (see diagrams below).

2. The CDL is getting power but it's not operating. This could be due to lack of use by the previous owner, or another reason.

Just to double-check: Park your car in a quiet place, and turn your key to the IGN position. Don't start the truck. Turn off the radio and blower and wait until your brake booster finishes pressurizing. Roll down your drivers window and press the CDL switch a few times. You will hear the relay clicking behind the glove box, but do you hear anything at all from under the truck? You should hear the actuator motor run for about one second.

IMG_9080.JPG


IMG_9079.JPG
 
Joined
Mar 14, 2019
Messages
40
Location
Maryland
Hey there, I have basically the same truck.

Since there is no difference in driving when the CDL button is pushed in, your CDL is not engaging.

Relay clicking under the dash is a sign that the wiring is good between the switch and control box.

The CDL detector switch is pushed only when the CDL engages, and that illuminates your dash light. So replacing the detector switch won't likely fix it, but it's not a bad idea to change it anyways. :)

The CDL dash light does not come on briefly when the car is started. The RDL light does because it is controlled by an ECU, but the CDL light is simply wired directly to the detector switch.

So the possibilities are:

1. The CDL mechanism isn't getting power. Check the wiring harness for damage, and/or probe the connector to see power is present (see diagrams below).

2. The CDL is getting power but it's not operating. This could be due to lack of use by the previous owner, or another reason.

Just to double-check: Park your car in a quiet place, and turn your key to the IGN position. Don't start the truck. Turn off the radio and blower and wait until your brake booster finishes pressurizing. Roll down your drivers window and press the CDL switch a few times. You will hear the relay clicking behind the glove box, but do you hear anything at all from under the truck? You should hear the actuator motor run for about one second.

View attachment 2237401

View attachment 2237398
that does answer some questions and yes i did listen to it last night in my garage and i heard nothing coming from under the truck ill double check for power to the unit tonight, if i got power than ill pull the actuator for some bench testing/ repair

thanks so much for the diagrams
 
Top Bottom