4WD Light Question (1 Viewer)

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Joined
Mar 11, 2020
Threads
6
Messages
63
Location
Lexington, KY
Ok, my 4WD light (88 LC) never engaged so I took apart my Instrument panel today to see if bulb needed replacement. I noticed two light harnesses just hanging and none connected to the 4WD box. Checked both with multimeter and both get power to them. Replaced bulbs and connected to 4WD box. Her is the issue...
1) I place the 4WD shifter on floor to Neutral and the 4WD light pops on.
2) I then place into 4L and the 4WD light goes off
3) I then place in 2H, hit the 4H (hubs locked), and the 4WD still stays off...wtf?
The t-case does as supposed to and goes into 4L & 4H. Any help appreciated. Also looking for two new instrument panel covers in blue if anyone has with good eyelets..one for the heater control/ashtray as well. Thanks

Cory
 
Sounds like the issue is the actual 4WD switch in your tcase. Simple to check. First of all disconnect the switch from the wire harness. The switch is on the tcase front nose cone on the passenger side, right behind where the vacuum shifter attaches (it's the one with the wiring coming out of the side of it rather than from the top). Short the pins together. Now go turn the key on without actually starting the truck and see which light of the two comes on. If the circuit is good the 4WD indicator light will come on. FYI it uses a 194 bulb. If that's good and you find the right socket for the 4WD indicator light go ahead and reassemble the dash since now you know everything at that end is good. The unused socket is for a catalytic converter overheat indicator that I just recently found out was a feature on JDM models.

On the transfer case switch, connect a multimeter to the terminals. In neutral and all 2WD functions there should be no continuity. In 4HI and 4LO there should be continuity. If anything's different, your switch is bad and needs to be replaced. P/N for that is 84222-60021 and probably about $70 to KY from Partsouq (no affiliation).
 
Sounds like the issue is the actual 4WD switch in your tcase. Simple to check. First of all disconnect the switch from the wire harness. The switch is on the tcase front nose cone on the passenger side, right behind where the vacuum shifter attaches (it's the one with the wiring coming out of the side of it rather than from the top). Short the pins together. Now go turn the key on without actually starting the truck and see which light of the two comes on. If the circuit is good the 4WD indicator light will come on. FYI it uses a 194 bulb. If that's good and you find the right socket for the 4WD indicator light go ahead and reassemble the dash since now you know everything at that end is good. The unused socket is for a catalytic converter overheat indicator that I just recently found out was a feature on JDM models.

On the transfer case switch, connect a multimeter to the terminals. In neutral and all 2WD functions there should be no continuity. In 4HI and 4LO there should be continuity. If anything's different, your switch is bad and needs to be replaced. P/N for that is 84222-60021 and probably about $70 to KY from Partsouq (no affiliation).

Spook50, thanks a ton. Description and detail is perfect. I’ll do this today and see what I come up with. Cheers man!
 
The PO prolly removed the bulbs because of this problem. It might be a problem with the switch in the transfer case.
I’m slowly learning the guy I bought from was not on the level with hardly anything. Every time I dig into it something else pops up.
 
This is my guess without playing with the FSM and being under your truck:

Somebody took the neutral switch indicator and the 4WD switch indicator on your tcase and swapped them. You need to mecfhanically remove them from the tcase and swap them.

Note: the neutral indicator switch on your tcase is not to be confused with the Neutral start switch on the side of your transmission.
 
This is my guess without playing with the FSM and being under your truck:

Somebody took the neutral switch indicator and the 4WD switch indicator on your tcase and swapped them. You need to mecfhanically remove them from the tcase and swap them.

Note: the neutral indicator switch on your tcase is not to be confused with the Neutral start switch on the side of your transmission.
I hadn't considered that but that's very likely, given his symptoms.
 
Sounds like the issue is the actual 4WD switch in your tcase. Simple to check. First of all disconnect the switch from the wire harness. The switch is on the tcase front nose cone on the passenger side, right behind where the vacuum shifter attaches (it's the one with the wiring coming out of the side of it rather than from the top). Short the pins together. Now go turn the key on without actually starting the truck and see which light of the two comes on. If the circuit is good the 4WD indicator light will come on. FYI it uses a 194 bulb. If that's good and you find the right socket for the 4WD indicator light go ahead and reassemble the dash since now you know everything at that end is good. The unused socket is for a catalytic converter overheat indicator that I just recently found out was a feature on JDM models.

On the transfer case switch, connect a multimeter to the terminals. In neutral and all 2WD functions there should be no continuity. In 4HI and 4LO there should be continuity. If anything's different, your switch is bad and needs to be replaced. P/N for that is 84222-60021 and probably about $70 to KY from Partsouq (no affiliation).

This past month while on the freeway my 4wd light came on and stayed on until I got home. In the morning it did not come back on. I recently had the dash off and I am now thinking that I might have connected the "catalytic converter overheat indicator" (wasn't sure what that additional wire was for). I know that I need to swap out an O2 sensor and I'm thinking this could be causing it to overheat the catalytic converter. The 4WD light is not coming on when I push the button so I'm going to swap it today. I'm also thinking of connecting an overheat light if this is the case. Would be nice to know since its already wired for it. Thanks for the information.
 
Overheat light? Your post is very confusing. The Cats dont have sensors for heat. They have oxygen sensors for emissions and tuning your air fuel mixture.
 
Overheat light? Your post is very confusing. The Cats dont have sensors for heat. They have oxygen sensors for emissions and tuning your air fuel mixture.
If that other indicator light socket is for an overheat indicator then wouldn't it make sense that it would activate if the catalytic converter was overheating? Could the O2 sensor also indicate excessive heat? Just a thought.
 
The CATS on our OBDI vehicles have no temperature sensors whatsoever nor an indicator light for CATS in any function.

We have a check engine light that alerts you to emission related codes.
 
The CATS on our OBDI vehicles have no temperature sensors whatsoever nor an indicator light for CATS in any function.

We have a check engine light that alerts you to emission related codes.
This. The small gauge harness has the leads and socket for the cat overheat light, but the indicator housing, vehicle wiring and the sensors were only on JDM models.
 
Ok, my 4WD light (88 LC) never engaged so I took apart my Instrument panel today to see if bulb needed replacement. I noticed two light harnesses just hanging and none connected to the 4WD box. Checked both with multimeter and both get power to them. Replaced bulbs and connected to 4WD box. Her is the issue...
1) I place the 4WD shifter on floor to Neutral and the 4WD light pops on.
2) I then place into 4L and the 4WD light goes off
3) I then place in 2H, hit the 4H (hubs locked), and the 4WD still stays off...wtf?
The t-case does as supposed to and goes into 4L & 4H. Any help appreciated. Also looking for two new instrument panel covers in blue if anyone has with good eyelets..one for the heater control/ashtray as well. Thanks

Cory

Well I was finally able to get to the t-case today and it was just the sensors swapped. Switched them and good to go. Appreciate everyone!
 
I win! Guessed it in post 6.

Glad if worked out for you.
 
Well I was finally able to get to the t-case today and it was just the sensors swapped. Switched them and good to go. Appreciate everyone!
The MUD community always appreciates a post on the successful resolution of an issue :).
 
Well I was finally able to get to the t-case today and it was just the sensors swapped. Switched them and good to go. Appreciate everyone!
Glad to see that was the case. In mine the ground wire had gotten pinched and severed in not one but two separate locations. Nothing like laying under your truck holding up a hot soldering iron.....
 

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