No 4wd, need help with troubleshooting

Hi all, I have an 04 v6 and my 4wd quit working. Last winter it was kind of a bear to disengage it but it would come out eventually. Then it progressively got worse this spring and summer. Parked it for about a month and a half(I have a free work truck I drive mostly) and went to drive it yesterday in the woods and the 4wd was nowhere to be found. No indicator light, no nothing. So I did some research and found it was most likely the A.D.D. On the front diff. Upon removal and disassembly I noticed that the previous owner must've replaced this part very recently seeing as how it was in near perfect condition. The factory service manual only has the diagnosing method for a vacuum operated actuator, mine is a electronically operated actuator! I read somewhere that the transfer case actuator won't work unless the A.D.D. Is activated, well neither are working. I took the transfer case actuator apart and even though there was some moisture and mild rust, the contacts and armature of the motor were clean enough in my opinion to work, but I cleaned them anyway and reinstalled to no avail! The only noise I hear when I push the 4wd button is the sound of possibly a relay under the radio, nothing else. Help!!

 

Okay, so, you say the PO did work on the hub. Are we sure he did it properly? If it was a weak link previously I would start there.

 

It seems he replaced the ADD, but it's worked fine for the last 2 years and looks brand new.

 

its curious that there are no lights. normally you would get flashing 4wd to indicate its not working. have u checked the fuse?
you can also check the motor , by putting 12v on pin 1 and 5 or vice versa to make it go one way or the other to confirm that they are good...
i think pin 1 will be the right most pin looking at the connector on the motor.

 

If you are sincerely interested in trouble shooting the 4x4 system, check the 20A 4WD fuse and if that isn't the culprit buy a quality voltage meter to rule out the electrical side of it. The EWD goes into some depth on how to trouble shoot that part.

 

could be two different spots, the Tcase or the ADD crap. push the button and see if the driveshaft spins, if it doesnt then you know the tcase works then work you way up

 

Which motor? The transfer case or add? I have both motors off and I can manually lock it in 4wd on the transfer case by spinning the plastic gear underneath the black plastic motor cover and when I do that the light flashes. I can also manually slide the collar on the front diff that locks the right cv shaft into drive. So I know that both the diff and transfer case are functioning. The fuse is ok.

 

Neither motor is being activated. I can manually lock it into 4wd

 

The fuse is good and I have a good voltmeter, what is the "ewd"? I've been looking for a way to troubleshoot.

 

Gotcha. Anybody have a diagram? My Haynes manual only gives the vacuum operated add testing procedures.

 

I do. I'll see if I can scan it tonight.

 

Thank you very much

 

Sorry low-tech approach, if you want these emailed in better rez, pm me.

From 2004 EWD:










2004 FSM A.D.D System:








2004 Transfer Case system (w/ 2-4 push button):

 

Very helpful

 

Thank you very much I'm gonna dig in tonight

 

Ok guys I did some poking and prodding, hooked up a battery to both the front add actuator and the transfer case actuator and the motors turned in either direction. I checked the incoming harnesses and I have no power, I don't believe my truck has a relay for the 4wd system. I also checked my switch on the transfer case selector and it checked out ok.

 

Well thanks for checking back. There's a 4wd ECU under the stereo in the dash w/ the 2-4 push button transfer case. The j-shift has the relay.

Please explain the "incoming harness" you refer to?

 

I'm referring to the female plugs for both the add actuator and tcase actuator. What about the 4wd unit that is under the fuses and where the "gray wire mod" is done? What is the difference? Any ideas? I really appreciate all your help

 

That's for the e-locker.