4wd vsv not working properly.

[adkins]

So I found that my 4wd were flashing this weekend. Started doing some research today.

From what I find I have vacuum too the two valves on the driver fender. With "4wd" button off I have 14 volts at both valves. Got vacuum on outlet of blue valve but not red valve. Press button and it stays the same way.

I would have to assume that maybe there is a bad really somewhere. I don't think there is a break in the vacuum line going back to the actuator behind the diff.

 

[TheDurk]

So I found that my 4wd were flashing this weekend. Started doing some research today.

From what I find I have vacuum too the two valves on the driver fender. With "4wd" button off I have 14 volts at both valves. Got vacuum on outlet of blue valve but not red valve. Press button and it stays the same way.

I would have to assume that maybe there is a bad really somewhere. I don't think there is a break in the vacuum line going back to the actuator behind the diff.

Well, you should only have voltage (and vacuum on the outlet) on one valve at a time. From what you wrote, sounds like you have more than just a problem at the red valve. Voltage should switch sides between 2wd and 4wd. This is usually an issue with one of the sending switches on the TC.

 

[adkins]

I started my troubleshooting over. Left the valves plugged in while checking for voltage. Had zero volts at the brown/red one. And 14 volts on the blue one. Nothing seems to change when i press the 4wd button. But im not 100% on whats suppose to happen when you press the switch. Is the center actuator suppose to engage? Then when you go to h4l it pulls in the front?

 

[TheDurk]

I started my troubleshooting over. Left the valves plugged in while checking for voltage. Had zero volts at the brown/red one. And 14 volts on the blue one. Nothing seems to change when i press the 4wd button. But im not 100% on whats suppose to happen when you press the switch. Is the center actuator suppose to engage? Then when you go to h4l it pulls in the front?

Button puts TC actuator in 4H and engages front diff by switching the vacuum valves. In H4L, TC switches to low range.

And you are sure the 4wd light comes on but nothing happens at the VSV? I am having a hard time thinking how that is possible.

 

[adkins]

Got a little bit of time to check a few things. Verified that the trans case actuator has 35 ohms. The wires that power the actuator have continuity. And one of the switches that is attached to the actuator is bad. The one closer to the front does not make and the rear makes and opens when pressed and released. So I guess I'll start with the bad sensor.

 

[wake_rider]

Got a little bit of time to check a few things. Verified that the trans case actuator has 35 ohms. The wires that power the actuator have continuity. And one of the switches that is attached to the actuator is bad. The one closer to the front does not make and the rear makes and opens when pressed and released. So I guess I'll start with the bad sensor.

Reviving from the dead, but I'm having the same problem. Did you ever find a solution. I'm getting no switching at the VSV's, but my 4wd indicator flashes at all times with no change. The front diff will engage/disengage if I manually pull a vacuum to either side with a vacuum gun, so I know that front actuator is good, but I'm getting no change otherwise.

The three sensors I can access on the bottom of the diff and transfer case all have continuity when I press them in, so I don't know what's the next step.