4wd Light Doesn't Turn On 4H

No sweat. Next step is easy. Pull the switch and leave it connected. Depress and hold the contact button. If blue has ground, you have a good switch and problem is inside the TC--something is not engaging the contact button. If blue is not grounded, and white/black is, you have a bad switch.

When testing ground, I prefer red lead on a 12V+ source, and probe with the black lead. In fact, a 12V test light is better than a meter because it calls for a larger current. A meter can show low resistance, but sometimes the circuit can't pass a real current.

One more question The Durk, since we're at a stand still here. When you are in neutral, is your 4wd light on in your gauge cluster?
 
One more question The Durk, since we're at a stand still here. When you are in neutral, is your 4wd light on in your gauge cluster?

As you can see in my sig, I have a 5 speed with J-shift. But I assume autos are the same. Once it goes in, it doesn't matter what gear the trans is in. 4wd light stays on until you take it out of 4wd.
 
Hey all, anyone know why a functioning switch wouldn't be depressed to put my runner into 4H but work on 4L?

You're probably looking at the wrong switch. You must be looking at the 4L switch. 4H is a different switch. On the other side of the TC, same position.
 
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I don't have this problem, but I read the posts and I have to give a standing ovation to TheDurk and the rest of the experts on this forum who help beginners like me with not just one comment, but repeatedly walking through the troubleshooting steps.

I am so appreciative and so thankful for everyone's generosity!
 
Agreed, excellent tech advice.

This might be irrelevant at this point, I kinda skimmed to here. I had the same issue, 5-speed/j-shift. 4L worked, but not 4H.

My wiring was swapped on the t-case at the blue connectors. Is it possible yours got switched around too? Likely not, but worth a shot since you've seemingly exhausted everything.

We did a clutch on my truck and in a rush it got switched around. Took me 10 minutes to fix, after being nearly stranded in the snow when I went to the woods and discovered the issue. Good luck fixing it.
 
Couldn't agree more for all the accolades to TheDurk and everyone here that does such a great job helping people like me on this issue. Unreal. Secondly, I will try switching the wiring, makes total sense. One of those easy things that I didn't think to do. Thank you!
 
If [MENTION=10169]TheDurk[/MENTION] got paid for 4x4 issue advice on this forum, he'd be a millionaire many times over by now =)
 
Agreed, excellent tech advice.

This might be irrelevant at this point, I kinda skimmed to here. I had the same issue, 5-speed/j-shift. 4L worked, but not 4H.

My wiring was swapped on the t-case at the blue connectors. Is it possible yours got switched around too? Likely not, but worth a shot since you've seemingly exhausted everything.

We did a clutch on my truck and in a rush it got switched around. Took me 10 minutes to fix, after being nearly stranded in the snow when I went to the woods and discovered the issue. Good luck fixing it.

THAT WAS IT!!!! Hahahaha, I'm on cloud 9 right now. Thought the TC might be a gonner there for a minute. I learned a TON about this thanks to TheDurk. 99Runnr thank you for your tid bit. That did the trick. In the future, if anyone has the issue of 4H not working but 4L and N work great with no flashing lights on J shift, manual tranny. Switch the two blue plugs for the TC 4H 4L switches. That did it, working like a charm. Easiest and quickest fix of all time. You guys rock!
 
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Wow, I never thought of that one, but no one ever brought that symptom set to me before. (no flashing light makes this one different) When I did my clutch, I was careful to match the wire colors on both sides of the blue plugs.

At the end of the day, I learn from you guys, and that's why I keep doing this.

We would have hashed our way to this eventually, so it goes in the win column for everybody. Good deal.
 
Hell yea man. Sorry it took so long to figure it out for ya. Luckily for me, I was the one who touched it all lastly. We did my clutch and before the truck had EVER been in 4wd.

I started there cause it was incredibly simple. Glad I could ultimately help ya out. I've been out using the piss out of my 4wd since fixing it myself :pound:
 
I'm hopeful someone can help me out, as I have a similar but slightly different issue. 4WD dash indicator light (green) does not light up when 4H or 4Lo are engaged.

Let's start with what I have: 2000 SR5 4WD with 3.4L and 5-speed (same as [MENTION=10169]TheDurk[/MENTION] but +1 year). I have the J-shifter transfer case.

Here is what I've done:
  1. Made sure 4H and 4Lo are engaging even though my dash indicator light does not come on.
  2. Pulled instrument cluster and replaced bulb with a known working bulb.
  3. Unplugged 4H and 4Lo position switches and ensured I had continuity when 4H and 4Lo were engaged (used multi-meter to do so).
  4. Swapped 4H and 4Lo position switch plugs. I didn't think this was it, but I was willing to try at this point.

At this point, I am thinking the issue is the wiring between the transfer position switches and the dash bulb, or something is unplugged. I'm looking for where to go from here. I'm not sure where the wiring goes from the position switches - are there other plugs I could pull and check for voltage? I tried to follow the harness, but I was getting hungry and ready for a break.

A little more info: I replaced the valve cover gaskets in the spring, so maybe I left something unplugged... I thought I got them all, but anything is possible.
 
I'm hopeful someone can help me out, as I have a similar but slightly different issue. 4WD dash indicator light (green) does not light up when 4H or 4Lo are engaged.

Let's start with what I have: 2000 SR5 4WD with 3.4L and 5-speed (same as [MENTION=10169]TheDurk[/MENTION] but +1 year). I have the J-shifter transfer case.

Here is what I've done:
  1. Made sure 4H and 4Lo are engaging even though my dash indicator light does not come on.
  2. Pulled instrument cluster and replaced bulb with a known working bulb.
  3. Unplugged 4H and 4Lo position switches and ensured I had continuity when 4H and 4Lo were engaged (used multi-meter to do so).
  4. Swapped 4H and 4Lo position switch plugs. I didn't think this was it, but I was willing to try at this point.

At this point, I am thinking the issue is the wiring between the transfer position switches and the dash bulb, or something is unplugged. I'm looking for where to go from here. I'm not sure where the wiring goes from the position switches - are there other plugs I could pull and check for voltage? I tried to follow the harness, but I was getting hungry and ready for a break.

A little more info: I replaced the valve cover gaskets in the spring, so maybe I left something unplugged... I thought I got them all, but anything is possible.

The dash light is triggered by the position switch on the front diff (it's in a really nasty spot.) Sounds like that is your issue. The position switches on the TC tell the relay it is ok to engage the vacuum to the actuator on the diff. Then, when the diff engages the front shaft, the switch turns the light on.
 
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The dash light is triggered by the position switch on the front diff (it's in a really nasty spot.) Sounds like that is your issue. The position switches on the TC tell the relay it is ok to engage the vacuum to the actuator on the diff. Then, when the diff engages the front shaft, the switch turns the light on.

Thank you, and you belong in the 3rd Gen Hall of Fame for your knowledge! I retraced the schematic you posted, and there it was - not sure how I missed it, but I would not known where to find it as I was too busy staring at the vacuum valves. I crawled under and checked it, and I believe it's the position switch in the front diff as you recommended. No continuity whether the 4WD was engaged or not. I'll get one on order this week.
 
Similar Issue - Slightly Different

Thanks for all of the information that's been shared so far in this thread. Amazing support.

I'm dealing with a very similar issue that's been discussed.
I have a new to me 1999 4Runner, SR5, 3.4L 5-speed with a j-shift transfer case.
The original symptoms were: no dash 4wd light when moving j-shifter to 4HI, N, and 4LO. When driving in 4LO, it was obvious that it had shifted to LObecause it was slow to move, high revs, etc.

I replaced the bulb for the dash 4wd light with a known working bulb (I had the dash out anyway for something else)

Checking vacuum:
  • When in 2HI and shifting to 4HI, vacuum remained on the same nipple.
  • Shifting from 4HI to 4LO, vacuum switched to the other nipple.
  • Shifted back from 4LO to 4HI, and switched the vacuum lines to force it into 4HI.
  • This worked and allowed for 4HI driving.
  • Reset vacuum lines as they were originally. At no point did the dash 4wd indicator light up during this testing.

At this point I know that the vacuum lines and VSV are good. I also know that the front diff is functional.

Transfer Case Wiring Testing:
I then got under the truck to examine the transfer case position switch wiring since I know that the clutch has been replaced at one point.
  • Both switch pigtails have gray wires
  • The driver side switch(4LO) switch was connected to the blue wire with red stripe. The passenger side switch(4HI) was connected to the solid blue wire.
  • Although the harness look like they were installed correctly and didnt have much slack, I unplugged the switches from the connectors and switched them.
  • Now the driver side switch (4LO) is connected to the solid blue wire and the passenger side switch(4HI) is connected to the blue wire with red stripe.
  • When shifting from 2HI to 4HI, the dash 4wd light does not illuminate and the vacuum does not switch sides.
  • Shifting from 4HI to 4LO, the dash 4wd light illuminates and the vacuum switched sides.

At this point, the symptoms are identical to what 99Runner had with just switched wiring.
I am guessing that my passenger side 4HI switch is bad, but have not specifically checked it with a multimeter; that's the next step.

TheDurk or anyone else, do you have any ideas as to what might be causing the original issue?

Also, can someone walk through the process and tools they used to remove the transfer case 4HI and 4LO switches? Did you remove them from above or below - is one way easier than the other?

Thanks in advance for any troubleshooting advice that can be offered.
 
Based on that description, you have the 4HI and 4LO switches swapped plus a non-working ADD indicator switch.

On the J-shift transfer case, the 4WD light is lit when the ADD indicator switch (on the front diff) closes. If you were able to drive in 4WD without any indication on the dash, the ADD switch is bad.

If the ADD VSV's get power only in 4LO, then swap the 4HI and 4LO connectors on the transfer case. Transfer neutral indicator only does something on the auto trans trucks.

-Charlie
 
I ordered the front-diff ADD indicator switch (84222-35070) and installed it. The problem persists.

I took the opportunity to remove the two transfer case switches and tested all original switches with a multimeter.

The ADD indicator and the driver side (4LO) transfer case switches show an open circuit when the switch is not depressed. They each show resistance of ~10 ohms when depressed.
The passenger side (4HI) transfer case switch shows open circuit, both when not depressed and depressed.

I'll be ordering the passenger side (4HI) switch (84222-35110) and will try that next.
 
Resolved

Before the passenger side (4HI) switch (84222-35110) arrived, I used a jumper wire to short the passenger side female plug after shifting into 4HI. The 4WD light turned on and the vacuum switched to the 4WD side. The dash 4wd light remained illuminated as I shifted into 4LO.

Today, I replaced the passenger side (4HI) switch (84222-35110) with a new part and complete 4WD functionality and dash indication returned.

Thanks to all for the help in this thread.
 
4wd High not working but 4 Lo does work...

I have a 2002 3.4 4x4 automatic SR5 Sport. When I click the button for 4wd nothing happens. No lights or anything. When I stop, put it in nuertel then slide the selector up to 4Lo it engages and 4lo works fine with lights on and all. When I stop and move the shifter back down to 4Hi it disengages and the lights turn off and it's back in 2wd with the button still pressed... I tried different ways of enageing it and nothing will work for 4Hi but always works for 4lo. Any help or guidance would be awesome!!
 
4 wheel drive issues and gas light not working

The dash light is triggered by the position switch on the front diff (it's in a really nasty spot.) Sounds like that is your issue. The position switches on the TC tell the relay it is ok to engage the vacuum to the actuator on the diff. Then, when the diff engages the front shaft, the switch turns the light on.

I have a 99 sr5. I was recently hit while parked on the street in a front end collision. Had all the body repairs done and went to drive the car for the first time after the collision and the fuel indicator jumps all the way past empty and the fuel light flashes no matter how full the tank is. I then went to put the car in 4 wheel drive recently and the indicator light is not going on. Not entirely sure if the car is even engaging but both the gas light and 4wheel drive light worked perfectly with no issues before the accident. Insurance is not covering either issue as of right now because they said it can’t be proved they were cuased by the accident. Anyone have any ideas how they could have been messed up by either the collision or repair. I talked with a mechanic who thinks the sending unit for the fuel gage is not working. All the informaTion or help I can get helps!
 
I have a 99 sr5. I was recently hit while parked on the street in a front end collision. Had all the body repairs done and went to drive the car for the first time after the collision and the fuel indicator jumps all the way past empty and the fuel light flashes no matter how full the tank is. I then went to put the car in 4 wheel drive recently and the indicator light is not going on. Not entirely sure if the car is even engaging but both the gas light and 4wheel drive light worked perfectly with no issues before the accident. Insurance is not covering either issue as of right now because they said it can’t be proved they were cuased by the accident. Anyone have any ideas how they could have been messed up by either the collision or repair. I talked with a mechanic who thinks the sending unit for the fuel gage is not working. All the informaTion or help I can get helps!
No idea on the gauge (though, the sender could have been physically damaged by the impact?).

Was anything messed with on the driver's side inner fender? You need to figure out if you have 4WD working and no light or no 4WD at all.

- With the truck on, put it in 4WD - do you hear a click in the passenger footwell? (you can go in/out of 4WD while stopped to listen for it)
- While in 4WD, does the drivetrain bind up if you go around a corner (like a normal right turn on the street)?

There is a chance there is harness damage in driver's fender area, or maybe the body shop didn't plug something back in... Or the vacuum tank or line in the front end of the driver's footwell was damaged.

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-Charlie
 

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