I have a 1999 F350 7.3 4x4. My problem is the 4x4 is not working. I have locking hubs so it's not vaccum. I have power at the relays but no power at the switch or at the transfer case, tested with a test light. The fuses seem to check out and I have swapped the relays around. The 4x4 Light on the dash only lights up on the engine crank and will not light up any other time.
Any ideas?
Thanks

 

have you checked the power to the relays. Ive had same issues and used dielectric grease on terminals and work them in and out bunch of times. i guess the terminals get a enough crude and not allow go true contact. if this does work then I suggest to do all of them

 

I took the actuator motor off and it does nothing when putting 12v+- to the 2 big pins. I broke a bolt off of the three and ran out of mig wire.

 

I have no 4x4 yet. Put new motor on nothing. Checked and replaced selonoids nothing. Have power at the relays on pins 86 and 87 on both relays when they are out and a ground on center 87a with the ingnition on or off. Had the harness from the transmission out to the relays and all pins tested for continuity.(12v and test light) on the bench. With the harness and relays in I can not test any juice at the transfer motor when the switch is flipped any direction either plug. The selonoids make no click while installed at any time. Is their a wire that has power all the time or at some point so it knows what position the actuator is in? I have attached a picture of a diagram I found but not sure if it's for my e99 7.3. I have checked many fuses including the ones mentioned in the diagram as good.

 

At the switch in the cab on the dark blue wire I have 4.29 v in 2wd, 2.4v in 4x4 hi and 1.1 v in 4x4 lo. With the lights on the lt blue illumination light is on with 9v.

 

So, for future searches etc. 4wd drive would not work with new motor and new relays. I ended up taking a jumper wire and jumping the hot at the relays to where pin 30 would be and heard the actuator moving and then put relays back in and it works as it should.

 

I just joined today because I'm having the exact same issue. Just changed the solenoid and swapped the relays.

 

Put power (+&-) to the 2 prong plug at the actuator and see if it moves. The actuator is easy to remove. My problem was a bad actuator, but then.....

 

I'll try that later today but I'm pretty sure that my issue is that I'm not getting power to the shift motor for some reason.

Correction: I changed the shift motor, not the solenoid. Where is the solenoid located?

 

Wait is the solenoid just used to engage the automatic hubs? In that case, that's not my issue because I have Warn manual hubs.

 

I just checked and when I supply 12v power, it does turn, so my problem seems to be getting power to the shift motor.

Update: So I checked some more and I can hear the motor switching when I turn the ****, so it's looking like my problem is actually in the transfer case itself.

 

The actuator could be stripped

 

By actuator, do you mean the shaft in the transfer case or the part that turns the shaft?

 

Either or but I ment the electric motor

 

The electric motor is definitely turning the shaft, the shaft just isn't actually shifting the transfer case. I took it loose and had my wife shift it while I watched.

​​​​​Looks like I'm going to be rebuilding the transfer case.