How To Trouble Shoot 4x4 Actuator

Quick update:

I checked the 6 prong terminal on the actuator after reassembling it by applying power to the number 1 and grounding 2. The actuator arm moved fine. Switching power and ground caused the arm to move back the opposite direction so it appears to be functioning as intended.

I mounted the ADD back onto the front diff with the gray sleeve and the actuator arm centered so that the sleeve could move left to right freely. I also connected the wiring harness and the vacuum line.

No change, still getting the flashing 4WD and 4LO lights without being able to actually engage the 4WD.

What next? Because I’m lost as hell on what I’m doing wrong.

 

Right there with you. I’m a about to order a new/used actuator to see if for whatever reason that is giving me the problems. At my wits end with this bitch to be honest.

 

This goes for both 2nd and 3rd gen 4wd actuators. Assuming you already troubleshooted the small motor contacts and they are now soldered. This should be fixed now on the 3rd gens. However, there is one more place where you can have contact problems. It's the tiny switch you can barely see, you would normally ignore it. If your actuator been out there for a few winters or you have a cut on your breather hose (like I did) and you get water inside it will corrode the insides of that little switch and then the computer won't have the response that the actuator did in fact moved the fork and ingaged the 4wd. Since the computer doesn't know about it out won't let you shift to 4LO.
Here is the fix. Take that little switch apart very carefully and clean those tiny contacts. As simple as that.

 

So just throwing this out there - right after I had my actuator off and back on the 4x4 and 4lo lights flashed a couple of times and went out while I was in 2hi. Then the other day the lights started flashing again and didn't turn off this time except once briefly while driving. Couldn't engage 4x4 with the lights flashing either. Drove it like that for a couple of days then today inspiration struck - unplugged the electrical connector, blew on the pins and plugged it back in and voila, no flashing lights, 4x4 works again. So check your connections!

 

so i did some diagnosis on my truck with similar issues.

Can anyone confirm the part numbers for the two limit switches on the transfer case actuator?

 

Ended up getting an entirely new transfer case from a local shop since it was less than half the price of what the dealership was going to charge for just the transfer case actuator. No more flashing 4x4 light

 

Purchased a used but in perfect shape actuator from another TW member. Threw it in today and it didn’t change anything. I removed the transfer case actuator motor, tested it, greased it up and reinstalled it. I cleaned up all the connectors on everything again for the 50th time. Reset the ECU and it is all good now. After several months of trying to fix this damn thing I finally got rid of the blinking lights.

 

After the dealer fixed the pinched wire. My 4x4 was working again. But after a week or two the 4wd/4lo light started flashing again. So i unplugged the transfer case swithches(like i usually did for them to go away)But they stayed on.

So this time I disconnected the battery for awhile and also unplugged what i think is the 4wd ecu. The lights havent been back on in a month.

Is the 4wd ecu behind glove box on far right? Grey box?

 

mine is black but yes its behind and above the glove box on the passenger side of the glove box. If you unplugged those then the 4wd system will not turn on the dash lights.

 

I actually just reset the main ecu and it started working.

 

by main ecu do you mean the 4wd ecu or truck ecu?

 

Truck ECU. But honestly I think it would’ve worked just turning the truck on and off a few times for it to learn that a new working part was in there.

 

thays good to know.

 

I also need the part numbers for the limit switch in the t case actuator. Anybody?

 

I have a 3rd gen and recently went thru a stream crossing water was about 3ft deep maybe a little more. After being on the trail all day and going back to pavement driving switched to 2 wheel drive everything worked no flashing light. Stopped for a gas fill up and started up and green 4x4 light was flashing. Tried to engage and disengage 4x4 but nothing but flashing light. so started to drive to camp and after a few minutes of driving light went out. Did not try engaging 4x4 until trip home was over. When i arrived home light was still off truck engaged and disengaged 4hi 4lo no issue . Now light comes on occasionally but goes out on its own after a few minutes of driving any time light flashes cannot engage 4lo or 4hi. Does the 3rd gen share the same actuator problems? Any help would be good ,warranty well passed by. Thanks

 

the symptoms sure sound the same, look up the part numbers and if they are indeed the same then rest assure the diagnosing and corrective measures will be the same...

 

it looks like the part numbers are the same, i see them being advertised as 05-17 tacoma

 

APDTY 134104 4WD Front Differential Shift Fork Actuator Assembly Fits 2007-2016 Toyota 4Runner or Tacoma 2014 Toyota FJ Cruiser (Electric & Vacuum Operated; 4-Wheel Drive Models With V6 Engine)does this look correct?

 

not 100% sure where you pulled that from, but that part number looks incomplete...
here is a picture of the part label from one that I purchased some years back

 

I would suggest avoiding aftermarket.
The dealership charges an arm and a leg for these, you can find OEM toyota ones over on ebay for a fraction of what the dealer quotes.