97 Limited 4WD not engaging.

[power10er]

4wd will not engage. My limited has the two position TC with the 4wd engage push button. I get nothing when I press the push button on the shifter. No usual click from the relay/ecu and no actuator running sound either. The indicator light does not come on. The 4wd fuse is good. I verified the front axle does not lock in (spins freely). The VSV’s do not swap automatically, but I don’t think they’re ever getting the signal to swap since nothing happens from the push button. I did verify that the front axle does lock in when I manually swap the vacuum hoses at the VSV’s. (Does not spin)
I am leaning towards it being my 4wd ECU as the issue. Any other advice would be appreciated.
also, help me locate the 4wd ECU!!! Resources are sketchy on that.

thanks,
Brian

 

[brillo_76]

4wd will not engage. My limited has the two position TC with the 4wd engage push button. I get nothing when I press the push button on the shifter. No usual click from the relay/ecu and no actuator running sound either. The indicator light does not come on. The 4wd fuse is good. I verified the front axle does not lock in (spins freely). The VSV’s do not swap automatically, but I don’t think they’re ever getting the signal to swap since nothing happens from the push button. I did verify that the front axle does lock in when I manually swap the vacuum hoses at the VSV’s. (Does not spin)
I am leaning towards it being my 4wd ECU as the issue. Any other advice would be appreciated.
also, help me locate the 4wd ECU!!! Resources are sketchy on that.

thanks,
Brian

Its possible its the ECU though it more on the rare side. I would suspect the actuator its self. As if it will not engage into 4wd. I would think the light would not engage along with the front VSV. Remove the actuator power connector and test for voltage while you have someone push the button on and off see if you are seeing 12 volts going to the motor actuator. If we have power at the actuator the brushes in the motor are most likely warn out and may need a replacement actuator. Testing is the only way to know for sure.

 

[JustTroItIn]

I haven't had to play with this on my Limited so not sure if it's the same but on my SR5 the culprit was the relay in the passenger kick panel.

 

[mhelvestine]

97 4 runner 4 wheel drive issues

My 97 4 runner will not engage my 4 wheel drive. The indicator light on the dash lights up but I have nothing. Went under the hood and on the drivers side I can change the vacuum on the actuators and it engages Any Ideas ?

 

[AuSeeker]

My 97 4 runner will not engage my 4 wheel drive. The indicator light on the dash lights up but I have nothing. Went under the hood and on the drivers side I can change the vacuum on the actuators and it engages Any Ideas ?

When you say "change the vacuum", what do you mean, how did you do that?

 

[phattyduck]

My 97 4 runner will not engage my 4 wheel drive. The indicator light on the dash lights up but I have nothing. Went under the hood and on the drivers side I can change the vacuum on the actuators and it engages Any Ideas ?

Sounds like you should leave the vacuum lines 'swapped' then?

Check that 12V to the two ADD VSVs swaps between the two when 2WD and 4WD is selected. Make sure the front driveshaft (between transfer case and front diff) spins free when in 2WD.

-Charlie

 

[2TH4IST]

Doesn't sound right. If you don't have 4wd the light will not come on as it uses the t-case switch and the switch on the add actuator housing, to turn the light on. If the light comes on the add actuator has locked the axle shaft and your t-case is in 4h or 4l.

I got a spare set of vsv's and the red solenoid was sticking. So I used some wire pig tails to jump to battery and sprayed brake cleaner into the ports (fill them up) then quickly cycled the solenoid and it freed right up. But I had one that was completely dead no matter what I did.

 

[mhelvestine]

Up under the hood on the drivers side wheel well it has (2) Vacuum modules when I take the line from one which has the vacumm on it and place it on the other the 4 wheel drive engages when I put them back the way they were it disengages.

 

[AuSeeker]

Up under the hood on the drivers side wheel well it has (2) Vacuum modules when I take the line from one which has the vacumm on it and place it on the other the 4 wheel drive engages when I put them back the way they were it disengages.

I own a 4th Gen so I don't know the modules you're referring too...BUT I would trace the line that doesn't have vacuum to see if it's broken became disconnected, etc. and or also find what controls/switches on the vacuum going to that line to find out why there's no vacuum.

 

[vegask]

With the transmission in Neutral, what happens when you shift into 4-low? Putting it in low should force the 4wd rail in the tcase into position.

 

[vegask]

Here is the wire diagram for a 97 4wd circuit just in case you need it.

4runner-4wd.pdf - Google Drive