TheDurk

Stupid question: Did you check your "4WD" fuse?

I'd also check your button. It switches ground so don't expect 12V+ there.

johntnj

Fuse is good first thing I checked. Next I climbed under the truck and the breather hose was off the actuator on the t case. Put I back on checked the other hose on top from where the shifter is to the body. That was cracked so I replaced it. Checked the selector switch, the sensor on the t case and speed sensor all work the way they should by the book. I put juice directly to the front actuator and it goes in and out. Checked the t case actuator and nothing. I but the truck up on stands and the front drive shaft is locked in to the rear drive shaft so the both spin when you turn the wheels. I can unlock the front wheels so I'm in 2wd but the front shaft still spins when you turn the back wheels. I was trying to eliminate every possible thing before I went and got a new actuator and put it in or a junkyard t case. I don't mind spending the money or time on either I just don't want start throwing parts at it and hope it works. Only other thing I was thinking of was maybe its stuck internally. Was gonna try spraying some wd-40 in it thru the breather hose and see if it un sticks itself

osoquik

Try changing the tc fluid??

GWF545

I had this same problem in my 2000 4Runner Limited. I researched here and elsewhere and found that the sensor switches used in the front differential and transfer case are all identical. Further, I found that the manual transmission back-up light switch is also identical and used on many other Toyotas. Toyota lists these parts with different part numbers at significantly different prices ranging from around $60 to $100 which is really silly considering that they are really all the same part. There are equivalent aftermarket back-up light switch parts (some mfr's actually list them as front differential sensor switches) from Dorman, Beck/Arnley, and others. Here is a link to some at Rock Auto:

http://www.rockauto.com/catalog/x,ca...,parttype,4240

I ordered two Beck/Arnley 201-1788 switches from Rock Auto for about $16 each and replaced my front differential switch with one. The original did not test bad, but I figured since it was a common failure I might as well. The problem did not go away, so I removed the two sensor switches on the transfer case actuator and found one was bad, replaced it with the other new one, and the problem was solved. Thanks to the original posters who figured this cheap and easy fix and with these aftermarket parts its even cheaper.

WifesYota

Removed

Virginia4Runner

Like many others have already stated, thanks to those that figured out that in many cases a simple switch replacement is all that is needed to fix flashing 4WD lights and vehicle not coming out of 4WD.

You'll love my story. Last December my wife mentioned that her 4WD was not coming out and going back into 2WD when she pushed the M/M switch. I found this board and this thread an saw that the switches were a common problem and that the dealerships were often insisting on a replacing the actuator in the transfer case. I didn't have the time to track down parts and test switches so I took to dealership and told them specifically to test the switches to see if they were bad as it was a common problem. Low and behold they called me back to say that the actuator on the insider of the transfer case needs to be replaced and quoted $2,300 to do work. I asked if they tested the switches in the front differential and the transfer case and they told me they had and it was the actuator. I told them to put it back in 2WD and do nothing more. They charged me $105 for their work.

We didn't get much if any snow up in Northern VA this winter and I never got around to testing myself until last night. Sure enough when I pulled the forward switch on the transfer case i did not get connectivity with the switch depressed. I got a replacement switch today, installed it and the 4WD M/M works perfectly now. Lights blink while it drops into 4WD then solid green tires. Push M/M again and all lights go out and back in 2WD.

So for $80 bucks and a half hour of my time, I avoided being cheated out of $2,220 plus tax. I probably wont get back to dealership tomorrow but sometime in the next week or so, I am going to have a discussion about with the general manger of the dealership to get an explanation as to how this possible could have occurred (I know how, they intended to charge me for the most expensive repair possible, rather than actually fixing the real problem, I just want to see him try to explain it to me. My guess at this point is that they would have simply replaced the switch and then told me they replaced the actuator and charged me the $2,300.00. I also want me $105 bucks back.

My wife and I have been 14 year customers of the dealership (bought vehicle new there and have had all service done there). We just bought a new 2013 Sienna Limited from a competing dealership and the GM will be told he just lost a 14 year customer and all future service work on both the 4Runner and the new Sienna despite them being the closest dealership.

Cmayer

Delete

FunRunnerGal

First of all thanks to the person who started the thread and originally did all the work and figured out what the issue was with the front diff sensor!

Second thanks to the people who took the time to share and confirm it really works!

Third thanks to all the folks who took the time to post pictures!

Fourth thanks to the people who said you could use M.E.K. or contact cleaner to just clean and re-use the part for the cheapest fix

I was going to just go buy the part from NAPA, but I didn't have the original Toyota part number with me, and I tried to find this thread on my smartphone and the guy at the counter tried to look it up too on their computer but no avail. So I just said to heck with it and picked up some QD Electronic Cleaner spray that was a NAPA brand for like $8.99. They also had the 27mm socket there for $6.99.

I'd just like to say do not be intimidated about giving this a try. Honestly all will happen is you will get a bit dirty. You will not hurt your vehicle trying it!

I am a woman and have done some mechanic work. My father made dang sure I could do basics like flat tire repair and when I was 16 and my mustang broke down he refused to help me. Made me get a repair manual and I replaced BY MYSELF my water pump, the radiator, and the master cylinder. I also had to bleed and pump the lines alone using a cinder block! It can be done! I also have a scary memory of putting in a new brake light switch which is no small feat as I was upside down with my head under the brake pedal and that was a fun time...

Anyways I can say I guess I am not the average woman but it has been over 2 decades since my "mechanic" days but again thanks to everyone here for the concise sharing of info and details as I was not afraid to give it a try.

The best part? It actually worked! My 4WD sensor (at least so far) is not going on and off by itself anymore with the blinking blinking blinking that was aggravating! Plus now the 4 wheels on the dash sensor light up green immediately and it is very responsive!

I am uploading now to youtube a video series about it as when I first tried to seach youtube there are NO videos that I could find abou this issue or even for 4WD on these models either. I don't know how to edit so there is a total of 4 videos but maybe those will be helpful to others

Thanks again so much everyone! I joined the forum just to post and share my success on this to keep the thread going and say it is still a relevant issue for people and that the fix does seem to work.

A side note about the "stealerships" as I love to also use that term:

Well perhaps a belated intro: My 4Runner is a 1999 Limited that I got used from a Toyota dealership. Had close to 155,XXX miles on it so I knew it was used but I WANTED the '99 from all I learned here and on some other 4Runner sites. Last year made in Japan, higher ground clearance, wanted the Limited for the leather, the rear diff, the moon roof. Well... the freakin' moonroof leaks

Oh well, it's a 14 year old vehicle. The rest is in excellent condition, carfax clean NO accidents, etc. It wasn't a deal killer for me. Well at the dealership parts & service they quote me $740 for a new sunroof! That is just for the window. Not even the track mechanism. This was after their "mobile leak" guy had me come out to meet him there only to tell me the window is leaking (ya, knew that one) and the gutters/drains work fine (ya knew that too as I did my own diagnostic). So I hear 2 different stories from the dealership: Yes we can install it here. We have to take the headliner out and it is a big deal (that one AFTER THEIR LEAK GUY told me it just pops out from the top by 4 screws!), the other was NO we don't do it here. They said Safelite does them. Well NO THEY DON'T. I called them.

The silver lining is that I called around, I can get a reconditioned one for under $300, and a guy who does them will install it for $60 and he confirmed it is just a matter of the 4 screws and popping the window out. My long rambling point to this entire post is do not listen to "the experts" first all the time. It never hurts to look something up on the internet or ask a question on a forum or make a few phone calls. I was sooo peeved that the dealership was going to charge me so much for the same part I can get for less than half- plus I have ZERO confidence in them now since one guy tells me they can do it there and have to dismantle my interior and another guy says no, you have to go to XYZ and that company says no also! I mean I really do believe every post here where people said they were quoted $2,000 for this easy peasy fix!

I will come back and post here the links to my youtube videos once I get them loaded...

FunRunnerGal

Robb235

I replaced the sensor on the front diff as well, but it didn't fix my issue. I also haven't properly diagnosed it either. For the price, I just went ahead and did it.

Pressing the M/M button, it'll sometimes go into 4wd, but more often than not the lights will blink. When I put the transmission in neutral, it'll slide into 4wd (usually helps if I'm rolling). Same thing when going back to 2wd.

Sent from my iPhone using YotaTech

FunRunnerGal

Ok here are the links to the first 3 videos. I do not know how to edit videos otherwise I would have and made them shorter and maybe only 2 videos so sorry they got broke up into 4 parts. I am loading part 4 now...

Malfunctioning 4WD Sensor Toyota 4Runner Part 1:

Part 2:

Part 3:

FunRunnerGal

FunRunnerGal

Here's Part 4:
http://www.youtube.com/watch?v=4607g...ature=youtu.be

FunRunnerGal

FunRunnerGal

Ok update: ONE time today it did the blinking thing all on it's own again but for only about a mile. It still goes in/out of 4WD perfectly when I press the shift on the fly 4WD button which tells me the front sensor benefited from the cleaning I gave the front sensor but likely one of the other sensors is still having issues.

So... can someone re-post the locations of the other sensors and how many? I believe someone posted that there are 2 near the mid part of the car about where the driver sits and I was able to find one there on my 1999 4R Lmt. I think it was a 2000 or 2002 that the person posted about ther being 2 sensors there. Also I think someone posted before that there are 6 sensors total?

I may just break down and buy some new sensors and replace them if anyone thinks that would work better than the clean-job I did on them.

Can someone correct or confirm that info please? I got a Haynes Repair Manual today for my year range of 4R so hoping I can get some info on the sensors and locations out of that.

Plus I am thinking about starting a thread or looking for one here about replacing the sunroof. The gutters and 4 drains all work and drain fine with no leaks. I have confirmed that the leak is at the seam where the hard plastic meets near the front on the glass and there are a couple of spots on the outer rubber gasket that have been compromised and leak into the seam when I blew air into that space. It is held in by only 4 screws apparently. I got a "new" used sunroof with a 6 month warranty online for $175 shipped to my door. The dealership wanted $740!!!! I found a guy who will install it for $60 but if it really goes in/out with 4 screws I think I can handle that. It is the glass only- nothing wrong with the track mechanism.

I am near Tacoma/Olympia areas in WA for anyone else having the same issue with their sunroof and looking to replace. I can send the numbers/website for good deal on a reconditioned or good used or even new sunroof that is way way way cheaper than what Toyota charges.

Also going to take a crack at replacing the automatic antenna. It sucks on mine and doesn't give good reception for AM at all! I think I read a mod someone did with a regular antenna and if I can find one that will fit and it works will go that route. I had a Celica convertible that had the electric one and it failed too...

FunRunnerGal

Supermoney

Do 2001s have Front Diff Switches or not? I am going crazy trying to fix my 4Runners 4WD from engaging but I cannot find this sensor.

I replaced ALL 4 rear transfer case sensors, 2 on the rear 2 on top. STILL NOTHING.

Does my 2001 have a front diff switch because I cannot find it and if not what should I try next? I tried banging on the electric motors on the actuators and nothing either.

FunRunnerGal

If you go to your local Toyota dealership, they can look it up for you using your VIN from your˟vehicle. I was able to get a printout of the schematic and exploded blow out view of the engine and all the parts. I even got the part numbers which was nice because I could then have Auto zone look up and get me one of the sensors for way cheaper.

Good luck. I know I am more annoyed than ever tyring to get my issue figured out as well....

Fun Runner Gal

FunRunnerGal

Request here for others who have posted in the past for updates and suggestions...

I firstly took out my old front diff sensor and cleaned it and then replaced it. It seemed to work well with the 4WD working perfectly for the first 2 days, then slowly reverted to blinking, blinking, blinking all the time on the dash sensor.

Secondly, I went out and bought and replaced the sensor and again, seemed to "fix" the issue (No more blinking dash sensor and would go in/out of the 4WD by either pressing the button while driving or just shifting into low 4WD with the shifter).

It got me to thinking that the issue with the blinking from the sensor started about a week after I got the vehicle after I messed around with it in the first place. I am wondering if it isn't even the sensor but maybe just the transfer case is low on fluid level? I just need the time to be able to get under the vehicle and check it which I haven't thus far. Hoping early next week to do it. I started to think that could be the problem because the sensor doesn't blink until after driving down the road for maybe 10 or 20 minutes. Then it kicks in and blinks on and off throughout the time I drive it. If I catch it before it starts blinking I can even get it to go into and out of 4WD perfectly. But if I keep it in 4WD too long it will go out and start blinking again.

That is what makes me think the fluid level has something to do with it. Like it takes the vehichle time to realize the fluid level is low or for it to build up (or not build up) the right amount of pressure for the sensor to work properly. I'd love some feedback on this. I don't see any leaking fluid anywhere but I know a small amount leaked out when I first removed the original sensor to clean it, and less the second time when I removed and replaced the sensor. It also makes sense that the front end is the issue because the 4Runner is always in rear wheel drive until put in 4WD which engages the front end. At least that is my understanding of it.

The good news is that the vehicle still drives great even with the sensor acting up. Just annoying to constantly see the flashing, plus I got the dang thing for the 4WD in the first place to take up to the mountains in Canada for dog sledding in the next 3 weeks....

FunRunnerGal

FunRunnerGal

UPDATE: So I crawled under and removed both front skid plates so I could get to the front differential. I also checked the transfer case and it was full of fluid. When I checked the front diff I could see fluid has leaked everywhere and it was bone dry. SO... I checked the new sensor I had replaced and spent $40 on at Autozone and it had looked like it was the culprit for the leak and was leaking up through the electronic part into the plug in and not around the threads where it screws in. I had my suspicions because when I pulled it out of the box the entire thing spun around freely (the gray plug in part) and the original I pulled of the vehicle was as solid as could be.

So at this point I think I am to "Plan C..." I luckily kept the original part so I recleaned it with the electrical component spray and refilled the front diff that was empty of fluid. I replaced the part and took her out for a spin. Still blinking intermittently... BUMMER

So now I am just going to mess with the 4WD many times to get it in and out and hope that fixes it. It didn't start acting up until I messed with the 4WD button during the test drive so I am hoping it is just sticking and read on another forum someone had luck after putting it in/out of 4H and 4L like 20 times in a row. It is worth a try because even at way less than the dealership I can't afford on a hunch to replace all the sensors at $40-100 each. At least not until I tyr some other cheap/free suggestions.

FRG

costalot

Like so many before me, I created an account solely to praise SC4Runner and the rest of the contributors for creating and sustaining this incredibly informative thread. I have an '01 SR-5 and found the "No. 1" switch to be faulty. I'm going to order a new switch and hopefully have everything back to normal in no time. After discovering the bad switch, I jumpered the pins on the harness and the transfer case actuator immediately switched itself out of AWD. Then the front diff actuator did the same and my lights stopped blinking. HALELUJAH! I was very grateful I did not need to try the switches on top of the transfer case as 1) I didn't have that special wire-passing socket and 2) holy hell do they look hard to get at! I will post an update once I get the new switch installed if it doesn't solve the problem. Otherwise, assume I'm happily on my way! Thanks also to FRG for posting the videos. They were very helpful as well. I will do my best to create my own set of videos for the switch I need to replace and will post those as soon as I can create them.

FunRunnerGal

I super duper hope it fixes your issue. I wish I was more mechanically inclined and had the time to trouble-shoot my issue more.


I spent about 3 hours one day driving and putting it in/out of the m/m 4wd (the push button) and also 4L where you have to stop and put it into neutral first, then shift into the 4L. I read about putting it in and out of 4wd a bunch to see if that helps and it actually DID seem to make my problem better. Makes sense that this issue happens after vehicles get older and the 4wd not used very often and the blinking starts up AFTER someone attempts to use the 4WD. Like one of the little valve stem things on the ends of the sensors gets stuck or gummed up. Putting it in/out of 4wd frequently probably helps to lube up the system.


However I do still get the blinking issue, just not near as frequently. I took mine out for a 600 mile road trip (one way) which worked out to 12 hours driving each leg of the trip. A total of 1200 miles round trip. It was in some very cold areas and other than blinking for about 4 minutes after I was about 20 minutes away from home the damn thing worked PERFECTLY for the entire 12 hour road trip. Then, once I got there in the mountains and cold (in the 20's) it started blinking again and I couldn't use the 4wd).


On the return trip, after it was parked for almost 3 days it wasn't blinking when I first fired up the engine so I was able to put it into 4L and use it on the ice coated roads. I was also able to go back into 2H and use the M/H for 4H then after being on the road for about 2 hours it started blinking again and continued to blink at me for 2 hours straight. That was the LONGEST I ever had it blink at me. Usually it will only blink for 3-5 minutes at a time.


I was a little worried but thought "maybe" it had something to do with the temps and sure enough, as I worked my way south and got above freezing (in the 32-34 deg range) it stopped blinking and then proceeded to NOT BLINK the other 8 hours or so until I got back into the states.


I am thinking I am just going to have to quit being so cheap and just replace all the sensors and spend the few hundred that it will cost to do it myself.


I had checked the transfer case and front diff fluid levels (the front diff being low after the small lived replacement with the new faulty sensor that leaked my fluid out everywhere) but we didn't check the rear differential. That is also on the list to check before I consider replacing the sensors. I highly doubt it is an issue but who knows?


Fun Runner Gal

costalot

I'm far from an expert in these systems but I would definitely test the sensors before going and buying them. Some may be tough to get at but there's no sense in buying them first, especially if money is tight (and I can certainly relate to that!). The dealer can give you a diagram of where they are but it is a bit vague. When I get under my truck this weekend, I'll point out the 4 I can find and maybe the 5th which I hadn't looked for, yet. Even though the diagram shows one on the front diff, there isn't one there in the '01s but I'll video that, too, just to show people it's not there. Hopefully, that'll help you locate yours. Start with the ones on the transfer case actuator at the back of the transfer case. Best part about those is you don't need that special socket to allow for the harness to pass through it. While you're at it, you might as well check that switch on the front diff, too. Something tells me the cleaning job didn't cure the problem but sort of Advil'ed it, serving as a temporary relief from the headache but the problem came back. Best of luck!!

FunRunnerGal

Yes, it probably was just a bandaid but I was also upset that the new part was a dud and leaked like it did. The auto parts store counts it as an electronic part and won't take it back...


I actually do have the schematic from my Toyota dealership that they emailed me. I'd post a pic of it as it is exclusively for the '99 Limited models (they looked it up on my VIN) and it shows all the sensor locations and part numbers. But my computer died shortly after I posted the videos. We got a new hybrid laptop/touch screen (my hubby's) but I haven't played with it enough yet for posting pics and videos. I really should because I am sure there are many lurkers for this thread that could use the info on the location and part numbers.


I highly recommend just going to the dealership with your VIN and they can look it up and print it out for you!


FRG