4wd Actuators

How can you test 4wd actuators to see if they are working properly. A while ago my voltage regulator was acting up and it caused a few shorts. When this happened my truck got locked into 4wd. The fuse underneath the driverside storage compartment thing keeps popping. I replace the 15amp fuse and as soon as I turn the key it pops the fuse. I replaced the 4wd switch to start and it wasnt that. As far as I can see there are no ground wire issues

 

The truck is a 2009 4cyl 5spd 4wd obviously. Any input would be a huge help. Its bad enough I missed the frame recall by a year. That is an entirely diff issue

 

What fuse is it?
If the fuse is popping there’s likely a short to ground.
You need to find what’s on the circuit of the fuse that’s blowing, then start unplugging things and check for for a short.

If you let us know what fuse is blowing, we can probably help a bit more.

 

Its the fuse down underneath the steering column. There is a little drawer that flops out. Its right behind that drawer i think its a 15 or 30 amp for 4wd

 

I think I'd start with unplugging the 4wd actuators 1 at a time and see if it still pops, if it does unplug the 4wd ECU and see if it still pops.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Fuse number 13 is the one that keeps popping

 

I unplugged the 4wd actuators and it still pops the #13 20amp fuse in the diagram above

 

I unplugged the ECU under the glovebox like you said and its does not pop the fuse when i turn the key to on position

 

After doing those checks the truck is still stuck in 4wd and the 4wd lo light is lit up on the cluster

 

Ok next step is to check the actuator wires for a short to ground, leave both actuators unplugged and get a meter set to resistance or a test light connected to battery positive.
With one end of your meter connected to an known good ground touch each of the actuator motor pins (4wd ECU connector F13 pins: 1 (Blue), 2 (Green), 3 (Red), and 4 (Black/White)) you should see infinite or very high resistance, if any of them show 0 or very low resistance they are shorted to ground and you will need to trace wires to find the short. If using a test light connected to battery positive first check that it lights by touching it to a known good ground then touch it to each of the wires above, if it lights on any of them the one(s) it lights on are shorted to ground.

 

This may be a dumb question. When I check this with a test light should the key be on or off

 

Does not matter. But off is where you want it. Just looking for contact/short between the wire and truck ground.

I don't know the system, but it appears there are two actuators (F12 and F13)?? If so, when you unplugged them, did you do them one at a time? If not, you need to to in order to isolate the offending cable run - assuming that is what it turns out to be. If I'm wrong about there being two actuators...ignore me and carry on!

 

Preferably key off when unplugging things, the main thing is you want both actuators and the 4wd ECU unplugged when doing the short to ground testing.

The F12 and F13 are the 4wd ECU connectors, there are 2 actuators (1 on the transfer case and 1 on the front axle and if you have a TRD OffRoad there's a 3rd 1 on the rear axle for the locker) but they use the same connector style and pinout (2nd image). See the thread I linked in post 5 for more information on the 4wd system.

 

I finally have spare time to work on this. I will let you know what progress is made if any

 

I tested all the pins on the appropriate ECU plug with a test light and nothing made the test light turn on. I wasnt sure how hard I should pressed on the pins so I was being rather gentle. There is a crack on the transfer case actuator but I dont think it would be enough to render this issue. I will send the pic in the next post

 

So Pin#4 (White/Black wire) didn’t make the test light light up?

 

sounds like you have an open wire somewhere (broken wire) causing the fuse to constantly blow

 

If the fuse still blows with the actuator unplugged there's something other than the actuator blowing it, the crack may still pose a problem but we need to determine where the short is first.

A broken wire wouldn't cause a fuse to blow unless it was shorted to ground.