No CDL light

[pkelly72]

I have no CDL light on the dash. I turn the ignition on and there's no CDL light. Push the CDL button (7-pin mod) no light. Put in 4 lo. No light. Put in drive, reverse, no light. Checked fuses and they are fine. Pulled CDL sensor and gave it a tap, used a 9v and ran current through it while depressing it several times. Put back on. No light.

 

[pkelly72]

I ordered a new CDL sensor from cdan today. Hopefully this fixes the problem.

 

[retrofive]

I have no CDL light on the dash. I turn the ignition on and there's no CDL light. Push the CDL button (7-pin mod) no light. Put in 4 lo. No light. Put in drive, reverse, no light. Checked fuses and they are fine. Pulled CDL sensor and gave it a tap, used a 9v and ran current through it while depressing it several times. Put back on. No light.

Drive in figure 8s in loose dirt. Turn on and off. Notice a difference?

 

[pkelly72]

I should have said that when I press the CDL button I can hear it actuate but the light won't go on. Is that normal? This is while parked

 

[Tenzig Norgay]

I'd still go forward and backwards a few times. My light sometimes will not come on till I get rolling, sometimes it comes on immediately.

 

[pkelly72]

I tried going forward and backwards slowly and fast. Nothing.

 

[george_tlc]

There was no need to order the sensor if it was ok. You should have just used a meter on ohms range, should be open circuit (high impedance) with the sensor sitting there and nominally 0 ohms with the end pressed in.

You could have also just put a wire link on the harness side of the sensor plug to emulate the sensor being push in (0 ohms)...

Seems too obvious... you did actually check to verify if the CDL dash bulb isn't burnt out?? Ditto for the ABS light (depending on year).

Oh, wouldn't hurt to add your vehicle year etc into your signature so we know what you have...

cheers,
george.

 

[pkelly72]

Sorry about that - its a 97 LX. The abs icon lights up on the dash when the ignition is 1/2 turned without the engine running. No CDL icon lights up though. It has the 7-pin mod.

I honestly don't know how to check for
Voltage. I have a volt meter but failed my electronics class in school. I followed your write up and pulled out the sensor, whacked it, took a 9v and ran two lengths of wire to each terminal and then other ends into the sensor. I then depressed the plunger slowly several times.

I have not checked the CDL bulb and I'm not sure how to yet but I'm sure I can figure it out.

Great write up. Very easy to follow.

 

[george_tlc]

Set you multimeter to OHMS/RESISTANCE. Then if you touch the two probes together it should show close to zero ohms (just the resistance of the probe leads) and if you separate the probes it should essentially show infinity. Now you can measure the resistance of your sensor.

Google and the (near) infinite set of monkeys on the web will help you learn how to measure resistance. These a simple debug procedures that everyone should learn to do or you'll end up buying $expensive spare parts that aren't needed.

You need to open the instrument panel if the bulb is blown.

Use a wire link first to emulate the sensor being 0 ohms (which is what it would do if the center diff was locked). If the wire link lights up the CDL bulb then you know the bulb is good.

cheers,
george.

 

[pkelly72]

Set you multimeter to OHMS/RESISTANCE. Then if you touch the two probes together it should show close to zero ohms (just the resistance of the probe leads) and if you separate the probes it should essentially show infinity. Now you can measure the resistance of your sensor.

Google and the (near) infinite set of monkeys on the web will help you learn how to measure resistance. These a simple debug procedures that everyone should learn to do or you'll end up buying $expensive spare parts that aren't needed.

You need to open the instrument panel if the bulb is blown.

Use a wire link first to emulate the sensor being 0 ohms (which is what it would do if the center diff was locked). If the wire link lights up the CDL bulb then you know the bulb is good.

cheers,
george.

I appreciate your help.

Just to be clear, i need to lock the CDL then unplug the sensor and use a wire link on the harness side to see if the bulb lights up?

 

[yohavos]

You should be able to jumper the connector that goes to the sensor with a paperclip. With this done, and the truck's power on, the CDL indicator should light up.

You don't have to lock the CDL for this test. You're simulating the sensor in the "CDL locked" position by using the paperclip.

 

[pkelly72]

You should be able to jumper the connector that goes to the sensor with a paperclip. With this done, and the truck's power on, the CDL indicator should light up.

You don't have to lock the CDL for this test. You're simulating the sensor in the "CDL locked" position by using the paperclip.

Got it. I'll go try it now. I'll report back in a few

 

[pkelly72]

You should be able to jumper the connector that goes to the sensor with a paperclip. With this done, and the truck's power on, the CDL indicator should light up.

You don't have to lock the CDL for this test. You're simulating the sensor in the "CDL locked" position by using the paperclip.

The CDL indicator was there on the dash. First time I've seen it. I guess it's just a bad sensor.

 

[george_tlc]

The CDL indicator was there on the dash. First time I've seen it. I guess it's just a bad sensor.

Don't guess... Use the multimeter to verify if the sensor is operating correctly off the vehicle. Measure the resistance as you press in the spring loaded end. Should be infinite ohms sitting there and 0 ohms with your finger pushing it in.

At least you now know the bulb is functional.

cheers,
george.

 

[pkelly72]

Don't guess... Use the multimeter to verify if the sensor is operating correctly off the vehicle. Measure the resistance as you press in the spring loaded end. Should be infinite ohms sitting there and 0 ohms with your finger pushing it in.

At least you now know the bulb is functional.

cheers,
george.

I'll do it. I really appreciate your help. I'll check it again after I register the LX this morning. This should be fun.

 

[yohavos]

I'll do it. I really appreciate your help. I'll check it again after I register the LX this morning. This should be fun.

I just went through a whole lot with mine... glad you were able to verify the bulb worked.

Follow George's advice... many times these sensors can be cleaned out, too.

If you absolutely end up needing a new one, here's a thread I've got saved in my subscriptions for a cheaper alternative: https://forum.ih8mud.com/80-series-tech/446641-replacement-84222-12010-switch.html

If the sensor checks out, however, there remains the possibility that the CDL is not locking, even if you hear the actuator motor running. That's the issue I ran into.

As George said... first thing is to test the sensor.

Good luck!

 

[pkelly72]

Registered, insured, smogged and now the CDL comes on. Strange stuff.

 

[bruss95]

Mine comes and goes and it's annoying as heck! It'll work for a month then not. I changed the 4wd indicator switch and it didn't fix it. Then after about 100 miles on the HWY, I drive it in AWD/LO about 2 miles to a campsite. Then as I'm leaving I startup and the diff light comes on and locks. I can walk out there now and throw it in low with just the ignition on and the actuator spins and locks the CDL. Next week when the roads are mud bogs it won't lock.

 

[jameslibra]

I have the same symptoms, no light on the dash when i first turn on the ignition, press the cdl switch and the actuator whirrs and stops as it used to and still no light. ive tested the sensor and that reads 0.1 ohms when pressed and with the switch wired in but out of the transfer case the front and rear lockers can be heard trying to work so that all seems to check out. I just dont think it is locking. any other fixes?

so Yohavos, how did you fix it?
If the sensor checks out, however, there remains the possibility that the CDL is not locking, even if you hear the actuator motor running. That's the issue I ran into

 

[Tbkw01]

Piggybacking here. I just bought my landcruiser last weekend and I don't have the factory manual. Does anyone have a photo of where the CDL sensor is located and an example of the paperclip method? I am having the same problem. I did jack the right front tire and tested it for spinning. When in low and when the CDL switch was pressed it doesn't spin, but i get no light indication.