it's been raining here in northeast Florida so I tried engaging 4 hi while i was running about 35 mph. The indicator didn't come on at all. As soon as i got home, i tried engaging it again in 4hi and 4lo and also started driving in "s" pattern but it still won't light up. I even tried forward and reverse but still no go. I can't really feel the difference(tires binding) because it's been running cats and dogs here. what seems to be the problem? On the dash lights, are all indicators like seatbelt, check engine light and the rest of them light up when the key is in the "on" position? Is the 4wheel indicator suppose to come on also? Mine does not, so hopefully it's just a burnt-out light bulb. everything was working a couple of weeks ago when I engaged it in 4 hi and 4lo. But now nothing. Thanks a lot.

george

 

Check and make sure all of the ADD vacuum lines are hooked up. I believe if one of these comes loose/unattached down near the front diff, it will keep 4WD from engaging, thus no light coming on in your dash.

 

Thanks. How many vacuum lines are there for the 4wd mechanism?

george

 

try putting it in park, then shift into 4wd, then shift to drive

For some reason mine won't do on-the-fly 4wd anymore, and I've tried everything you have, when my dad tried it, he just put it in park and did it and it worked. I know it's pretty simple, but maybe it'll work for you.

 

You may also want to check the wire that goes from the light on the dash to the T-case. For some reason, when I first bought my runner and went out to the beach and got in some deep stuff, threw it in 4lo and didn't notice that it didn't engage till I got stuck. Took it to the dealer and they told me it was simply one wire that had come unplugged. I'm surprised they didn't try to ream me on that one, considering I knew nothing at all about 4wd at the time. THANK YOU YOTATECH!!!

 

Just check the vacuum lines and the wire that comes out of the front diff and everything is intact and tight. Iwent for a drive again and notice some binding on the driveline when i shifted to 4lo but still no indicator on the dash. Could the light bulb be burnt-out? Does the indicator illuminate when the ignition is in the "on" position? I'm running out of options here so just throw anything that you might think even if it seems unlikely. Thanks again for all the inputs.

George

 

Does anybody have any instructions in taking out the instrument cluster? I'm thinking of ripping it out and check if the lamp is burnt-out. It's definitely engaging in 4lo since it surges on first gear but not noticeable on 4hi. Hope fully it's just the lamp. Ohwell .

George

 

did you try my method? Because I went through the EXACT same feelings as you are now.

 

Yes I did. I even did it probably 10 times but it still doesn't work. Definitely engages in 4lo though. I'm still hoping it's just an indication problem. I'll tear apart my instrument cluster today and find out if the lamp is out. Thanks.

George

 

Rob,
Where you at in Detroit? My folks still live in Troy. On 14 mile rd. off of I75. Thinking about going there for Thanksgiving.

George

 

Actually I'm in Ann Arbor. But that was a good guess! I might be in Grand Rapids for Thanksgiving, but if you're planning on coming up, I would love to see ur rig.

 

WHOA!!!!!

DO NOT RIP OUT YOUR DASH!

That is a total PITA. Try the easy fixes first, than rip out your dash. Unless totally ˟˟˟˟˟ed up, you will always be able to shift into low gear in your transfer case so that doesn't mean diddly that you can do that. If you cannot feel a bind when making sharp turns in 4hi, than that means you probably have a vacuum line unplugged somewhere. Even on wet pavement you can feel binding, if you can't, wait for it to stop raining and try again, or take it to a gas station and do it under the awning.

I have had a vacuum hose come off before and the light not lighting up was the tip off...

 

Well, it's fixed. I decided to rip out the dash while waiting for the rain to stop. I switch around the lamp indicators and while at it decided to look check if my runner is prewired for an e-locker. I'm not sure if I am but i saw the connector for the diff lock switch with 4 wires into it. On the same wire bundle is another connector with seven wires. I was checking into Phong's write up but I can't see any resemblance. Anyway, I'll post another topic about this with some pics.
By the way, I really don't know what fixed my 4wd indicator problem. It's either the lamp or something else. Reason is, as I was backing out of my driveway in 4hi, I jerked the steering wheel when it hit the little dropoff at the edge of my driveway which connects it to the road when I suddenly feel some binding on the front wheels. I looked into the instrument cluster and lo and behold, the 4wd indicator was illuminated. This was after I put everything back together to drive test since it stop raining. Again, thanks a lot for all your inputs.

George

 

I think 44Runner is giving you the right scoop. You should listen to him.

The cycle of operation for the 4x4 system engagement is as follows:

The selector lever on the transfer case is moved into 4 high or low and that trips a switch. That switch supplies power to the vacuum switching valve that is on the driver's side fender wall near the exaust. That applies vacuum to the vacuum motor on the diff. The vacuum motor slides a slip collar into position locking two shafts together on the passenger side of the diff. When the vacuum motor reaches full travel locking the two shafts, it trips a switch that illuminates the dash light.

Now, you know the transfer case is engaging because you can feel the low range. Now you can start your trace and see if there is power going into and out of the position switches on the drivers side of the transfer case. There are two of them, one for each range (I think). If you have power going in and out of the switch when the transfer case is engaged you have verified proper switch function.

Now see if you have power to the vacuum switches on the fender and see if they are cycling properly. If so, check to see if you have vacuum in the system. If they are working properly and you have vacuum check for proper vacuum at the vacuum motor on the diff. One side should have vaccum and one should not, when the system is disengaged the vacuum should switch to the other side.

If that is working then you have to check to see if the motor is moving the shift fork. You may have to unbolt it from the diff to see. If it is making full travel then it should activate the switch. Verify power in and out. If you have both when engaged, then trace that to the dash light.

Now, slide the locking color manually to lock both shafts. If it moves all the way and couples both shafts and there is no differeential action in the front diff, you know when you turn one tire the other moves the oposite way, then you have a busted shaft in the diff.

So, if you do all those checks, you should trace out the problem in short order. A shop manual will be of a big help to you.

If you have had the transfer case out for any reason like a clutch replacement, I will bet you that it is going to be an error in which position switches on the case were reconnected.

However, with all that said, I will bet you a box of donuts that the problem is going to be in the vacuum system, like a disconnected vacuum supply line. That is the most common error after a supercharger installation. Sometime when the lines get old and hard they can slip off of the check valve that is located in the supply line on the drivers side of the engine, or a damaged line to the storage canister in the driver's wheel well.

Gadget

www.GadgetOnline.com

 

Man Gadget, do you have a side job working for Krispy Kreme or something?....you are always betting a box of donuts!

 

If you don't know, I am not going to tell you. If you knew you would get it.

Gadget

www.GadgetOnline.com

 

No wonder I am big fan of my "old school" 4wd system of manual hubs and manual transfer case. The system I have is much simpler and there is much less likelihood of failures like this. It's either in 4wd or it isn't. No vacuum lines, no solenoids, no sliding collars. The worst thing that could happen is a broken half shaft, but the possibility of that is very small. A more complicated system that makes it more convenient for the driver is not necessarily a great step forward in technology.

My two cerveza bottle caps.

 

I think I know, but I just felt like making the joke anyway.

 

It is a joke and you maybe the first to catch on.

Gadget

www.GadgetOnline.com

 

I have had both the electrical lead come un-plugged, which still lets the 4WD engage but the dash light just doesn't come on, AND in a seperate instance had a vacuum line get burned through, which doesn't let either the dash light or 4WD work.

I agree with not tearing into the dash (even though it's not THAT hard in my 2nd gen)......try to determine on dry pavement whether the 4WD is even engaging by having it bind the drive line while turning on dry pavement. I tore into my dash last week and found the bulb was fine. Heed 44Runners advice and try the easy things first!!!

I also agree that if it's not engaging, it'll be a vacuum line issue. There are two vacuum hoses that Gadget correctly references. Both of mine were connected at the differential. Don't think that if they are connected that all is ok with these. Trace the lines like Gadget instructs. I had to do this and I found that one of the vacuum lines had touched the exhaust header and had burned through.....effectively eliminating 4WD operation. Apparently when I changed the spark plugs or worked on the starter, I moved the vacuum line so that it touched the header.

If the front Diff is engaing (you get drive line bind) but the light is not working, check the lead coming off of the diff to make sure it hasn't come unplugged.....there is a plug connection right next to the oil filter on the 2nd gens (it may be the same for 3rd gens) and I knocked this loose during an oil change once.

That's the beauty of this Forum, you can learn from our experiences.......it'll make it easier for you.
David