Differential lock switch broke?

[cpetrice]

Bought a 2003 4wd model. Won't go into 4wd. Still under warranty, so I took it back, said it was the actuator, $2k, or they could replace the transfer case, $3k. The warranty isn't the best, they pay 50% labor and 50% parts....

I told them I didn't have that kind of money right now, not to fix it. Getting home, I started playing around, and the differential switch won't "lock".
When I push it, no light comes on, it just pops back out like its in the off position. for comparison, when I push the DAC switch, it stays down, the light comes on, push it again, it pops off, the light goes off. (along with the light on the instrument panel)

the 2h,4h and 4l knob seems to work fine, when I turn it the 4x4 dash lights flash.

not the same with the differential lock switch.
So, is it that the switch is broken?
I found an actuator new online for $285, and am mechanically inclined, and going to attempt to fix that myself if I have too.

First post guys/gals....be gentle!

 

[kai920]

.
So, is it that the switch is broken?

Sounds to me like it might be. I'd definitely consider that before going through the ordeal of replacing the actuator. Be sure you are using the correct procedue for locking the diff(tranny in neutral). Even if you weren't in neutral or the correct procedure wasn't being followed, you should still get flashing lights indicating thats it trying.

You also need to be in 4wd before you can lock your diff(someone correct me if I am wrong, I have AWD V8 model). Wouldn't make sense to be able to lock a diff and not be in 4wd already.

 

[ThreeFiveO]

I can remember if the switch is supposed to pop back up or stay down but if you suspect it should stay down, why not try pushing it and holding it down to see? If it works then you will know it's the switch that's bad.

 

[cpetrice]

I scoured the forum, found some "tricks" to get it to work. Switched it in 4h, drive forward 5mph, put it in neutral cost, stop, do it in reverse etc, heard it could have bound up, still didn't work.

Held the switch for 10 seconds, nothing, dash lights for the 4x4 just kept flashing. I ordered the switch ($60), going to try that before I mess with the actuator. If it's the switch, the dealer is going to get an earful!

 

[03_4x4Runner]

I scoured the forum, found some "tricks" to get it to work. Switched it in 4h, drive forward 5mph, put it in neutral cost, stop, do it in reverse etc, heard it could have bound up, still didn't work.

Held the switch for 10 seconds, nothing, dash lights for the 4x4 just kept flashing. I ordered the switch ($60), going to try that before I mess with the actuator. If it's the switch, the dealer is going to get an earful!

Test the switch with a ohm meter before replacing it. Do not start throwing unneeded parts at it.

 

[kai920]

Mine doesn't stay depressed. Check it on the way home

 

[kai920]

Are you sure 4wd is engaging. You stated above that the 4wd lights flash. They should go solid when engaged. If you are not engaging 4wd, that coud be why diff isn't working.

 

[cpetrice]

scenerios I have used....

press locking switch, then turn to 4wd
turn to 4wd, then press lock switch...

turn to 4wd, then hit locking switch for 10secs...
hit locking switch....hit 4wd....

drive forward....5mph..try it......
neurtal....try it....
reverse...try it...
From what I see...the differential switch isn't going to "on" or "off"
I'm gonna try to replace that if noone else has a better idea.

$60.
then I'm gonna see compare the actuator price, vs the 4wd ECU price, go with the cheaper...see what happens..then the actuator, going to narrow it down. any other ideas off attack?

 

[cpetrice]

Are you sure 4wd is engaging. You stated above that the 4wd lights flash. They should go solid when engaged. If you are not engaging 4wd, that coud be why diff isn't working.

from what I read, that means 4wd ISN't engaging, if the dash lights are flashing, they don't go solid. That tells me, 4wd differntial lock (which isn't lighting up)switch isn't working, 2wd,4wd and 4lo knob (which does seem to work, just flashes) is broke, or the actuator isn't engaging. I am gonna start with the cheapest and work foward.

 

[kai920]

According to the owners manual there are two fuses that control 4wd. One says "4wd control system" and the other states "all compenents in 4wd" I would check both fuses first to be sure one is not blown. Sounds like the controls are good, because you gets lights form the 4wd switch. Sounds like the signal is either not getting to the actuator or the actuator is not working.

If the signal is not getting to the actuator then its a fuse, or the ECU. I would start basic like you said. The actuator replacement I've hear is more than meets the eye. You have to drop the diff and disassemble to pull the actuator from what I understand. Keep us posted. Good luck

 

[cpetrice]

**UPDATE**
Got the new switch, put it in and like someone in the thread posted, it doesn't stay depressed, so the switch is good.

I saw 1 fuse for 4wd, driver side fusebox, didnt' see one under the hood. Is my old eyes missing it, or is it in another fuse box passenger side?(some cars have 2 fuseboxes in the cabin)

next plan is to climb under it and tap the actuator with a rubber mallet, heard it could be sticking. And from my Haynes Manual, it says on the v6 the replacement of the actuator is pretty much 4 bolts remove reverse, no dropping of the differential.

If that doesn't work, anyone know how much an ECU costs, where I can get one?
Thanks in advance.

 

[DaveS]

I really would not get into replacing the ECU - it's 99% sure your actuator that has seized up as the dealer said. Do a search here and you will see several others have posted with this issue - it is a known problem, especially on the V6 where folks often stay in 2wd all the time and never activate the actuator - "use it or lose it" seems to be the message . I have not seen a post yet that pointed to the ECU and they don't come cheap - all you will do is eat into the funds you need to pay for the proper fix, which is to replace the actuator.

 

[cpetrice]

Thank you. I read you post, researched and it does seem to be a problem. I bought a new actuator, on it's way. It was $286.
I just like to plan ahead, in case it is something else, I can be on top of it. Dealer says the ECU is around $300...so worse case scenerio....$586 for new ECU and actuator......sure beats the $2k I was quoted for the actuator alone! Will update when actuator is put on. Thanks guys.

 

[4RBob]

For me it was the 4WD control module behind the glove box. It was a few hundred bucks plus just a little labor to get it replaced.

 

[DaveS]

If you DIY please consider posting pics and a how to - don't think anybody has done it themselves here yet - especially if you find a way to do it without dropping the TC - look over at Yotatech for some ideas and info as well - I think there is more material there on it.

 

[cpetrice]

**Update**

Installed the new actuator. Followed the Haynes manual, removed the 2 skid plates to expose the actuator, and used a 1/4 ratchet to remove the 4 bolts. DID NOT have to drop the differential. It was a little of a tight fit, but came out pretty easily.

Issue that wasn't in the manual, was when you unbolt the actuator, fluid pours out, wasn't expecting it, but common sense said I should have.

Put on the new actuator, plugged it in and heard it whine for a sec (to reset I assume), put it all back together, no dice, 4x4 still didn't engage. That leaves the ECM. Ordered it, $295, if that doesn't work, I'm at wits end.

New differential locking switch, new actuator, new ECM, all the fuses are good, unless I'm leaving something out.
Sorry, couldn't take pics, moved recently and couldn't find the cable to plug my camera into the computer. Was a relatively simple job to install the actuator on the v6. Update when I get the ECM tuesday.

Note, when I put it in 4h, and push the differential lock switch, I can hear a faint "click" in the ECM behind the glovebox. Normal?

 

[BlackWorksInc]

I'm a little confused, are you still having issues with the vehicle actually going into 4WD as in 4Hi & 4Lo on top of your Center Differential Lock not working?

 

[cpetrice]

Oh no, I wasn't sure if the differential switch was working or not, so I replaced that first, it wasn't lighting up and I wasn't sure how it worked (I just got the vehicle). So I replaced the switch, and now the actuator, still not working. Gonna try the ECM next, that's the end of the line I assume!

 

[Burt]

I'm a little confused, are you still having issues with the vehicle actually going into 4WD as in 4Hi & 4Lo on top of your Center Differential Lock not working?

Could you please clarify what Blackworks had asked. I hope you're not trying to engage diff lock without verifing 4HI mode first.

 

[BlackWorksInc]

The clarification would help greatly, because the Center Differential Lock and the 4WD system, while essentially the same idea are done in two completely different manners in terms of ECM Logic and function.

Your 4WD will engage the transfer case to distribute power to all four wheels (essentially split the power between the two axles) but still allow the vehicle to compensate how much power goes up front via variables such as detected traction, wheel slippage, speed, ect. Engaging 4WD in either Hi or Lo has the same functionality, LO is just a different set of gearing from the transfer case.

While your Center Differential Lock will literally lock the center differential in the transfer case to provide a 50/50 split of power regardless of anything else. IIRC they are actuated by two different methods, 4WD being the actuator and the differential being electronically locked.