After searching for a solution to the problem I'm having with the CDL system on my 1992 FJ80, low and behold the thread at
CDL Problems Need Wiring Diagram is started and almost describes the exact problem I'm having. Even though they are similar problems, I didn't want to hijack another thread just to confirm my diagnosis of the problem.
From all the great information and knowledge contained on this forum, I'm hoping I made an accurate diagnosis of the problem.
After extensive testing of electrical components, my conclusion is that the diff lock relay is bad it has not worked for a while. With this lack of use, the diff lock actuator needs to be either cleaned up or replaced.
Here is how I came to this conclusion. If have missed something, please let me know so I can conduct further tests before spending money.
Background.
The Landcruiser is a recent purchase (within the last 10 days - I sold a Jeep Wrangler to buy the FJ80). The PO informed me that the transfer case would not lock up when shifting into 4L.
I confirmed that the CDL does not lock up when engaging 4L or with the dash switch (confirmed by jacking the wheels off the ground and also by driving). The CDL indicator light on the dash does not light up either. The dash light when the transfer case is in neutral lights up. There is no indication the actuator is engaging. The Diff lock relay only clicks when 4L is engaged via the shift lever. Both the 30 amp and 10 amp fuses are fine.
Troubleshooting.
I first tested the diff lock switch for proper continuity, by jumping wires and by switching out the 4-way flasher switch. The Diff lock would not engage.
Next I conducted a test of the diff lock relay on the DS kick panel.
All incoming voltage was OK (instructions from another post - continuity from pin 2 to ground; 12v to pin 3 - ignition on; 12v to pin 7 - ignition on - 4L).
I then bench tested the diff lock relay per the instructions in post #19 in the above thread. The relay passed all continuity tests (including applying voltage) EXCEPT for the continuity between terminals 6 and 7. I reversed the polarity and it still failed. The instructions stated "If continuity is not as specified, replace the relay".
***From this test, I concluded that the Diff Lock relay is bad.***
Next, I pulled, cleaned and tested the CDL sensor switch (on the front output of the transfer case) and the 4L sensor switch (on the rear of the transfer case). They were a little sticky but both tested fine after a little cleaning and exercise. I used a paperclip to jump the harness connector and neither triggered the CDL nor the indicator lamp on the dash. I checked for voltage and only one side of either connection had 12v (I assume this this normal?). I did not remove the transfer case neutral switch because the light works on the dash.
Next I tested the 6 pin actuator harness. I first jumped pins 4-5-6 and only had 12v at pin 2, but not pin 3. I then jumped pin 4-5 and only had 12v at pin 2, but not pin 3. There was no 12v to either pin 2 or 3 when I jumped 4-6. Pin 5 has 12v at all times when ignition is on.
***From these tests, my conclusion is because the diff lock relay is bad, the actuator is not getting the proper voltage to operate (ie; pin 3).***
Next I tested the actuator motor. I applied a 9v battery to pins 2-3 and the actuator did not operate. I reversed polarity and reconfirmed the connections several times and the results were the same. I'm hoping I did this correctly (I ran one wire from positive to pin 2 and the other from negative to pin 3 and then reversed polarity to test it that way also).
I then measured the resistance of the actuator motor (per instructions in post #19 in the above thread). The first step was to measure the resistance between terminals 2 and 3. The resistance was within specs. The second test calls for a measurement between terminals 2 or 3 and ground. My meter read 0.162 M ohms and it should be >0.5 M ohms per the manual. Per the instructions, it says to "replace the motor actuator"
***From this test, my conclusion is that the motor actuator needs some work and/or needs replaced.***
I tried to cover all the tests that were suggested in the above thread and a few others.
If I missed something, please let me know. If I'm on the right track, I can only thank you all for guiding me though my first Landcruiser troubleshooting session.
Steve
CJF
Linear Mode
