4WD troubleshooting help needed

[rmoore]

Hi All

I have a 97 4Runner that will not go into 4WD. I have went through quite a bit of threads trying to troubleshoot this. This is a Limited with the push button 4WD on the lever. It does not matter if you try 4WD Hi or Lo .This is what I have found so far. When you put it in 4WD the transfer case does shift the transfer case and locks the front drive shaft. I can watch it shift and then cannot move the front drive shaft, take it out if 4WD and I can.
The dash 4WD indicator does not come on. The VSV vacuum assembly does have vacuum ( about 15 lbs) on both the inlet sides of the brown and blue solenoids. Vacuum does pass through the brown side and goes though to the Actuator on the front diff. There is no vacuum on the outlet side of the blue.
There is only 12 volts on the hot side of the brown solenoid and does not switch to the blue side or go away when engaging the 4WD selector.
My question is how to back track the switching circuit of the VSV. I figure that is why the front Actuator is not moving. Some threads say there is an ADD relay and some say there is not. Then there seems to be a lot of places it may be located. So I am trying to figure out where to start looking for the circuit or source of the front VSV 12 Volt switching.

Thanks
Ray

 

[drabbits]

if you were having a actuator problem, you would see your 4x4 lights blinking.. well thats what I experienced with a bad front actuator on my '99.
"The dash 4WD indicator does not come on"
have you checked the 4x4 on/off button? maybe there's wiring issues at the push button area...
For the age of our vehicles swapping out your actuators wouldn't hurt. preventive maintenance

 

[Grenvilleter]

If your VSV's are working Ray, the next thing down the chain is the front diff.
The vacuum lines go to the vacuum actuator actually on the front diff.
Check the vacuum lines going down to your front end for splits, etc.

Possible the mechanism is seized in your front diff or simple as a hose pulled off the vacuum actuator down there.

There are guys who know this system that prowl around here and like you, I searched high and low for tips and ideas not being familiar with these systems.

I guess I would try to validate the integrity of your front diff now by applying vacuum to the front actuator (from under the truck, above the skid plate via whatever way you can eg: vacuum or very low air pressure (15-20 lbs).
Perhaps when you get in there you will see your problem.
You should be able to hear the front diff engaging and disengaging by applying vacuum directly to the bellows there.
Bellows is on the passenger side of the diff.

Not much help here I know but good luck.

 

[rmoore]

"There is only 12 volts on the hot side of the brown solenoid and does not switch to the blue side or go away when engaging the 4WD selector"

Thanks for all the replies, I just re-read my post and realized I screwed up on the most critical word, I meant to say the the VSV's are NOT switching because the voltage is not changing. So that VSV's are not being told to switch.


Thanks
Ray

 

[TheDurk]

"There is only 12 volts on the hot side of the brown solenoid and does not switch to the blue side or go away when engaging the 4WD selector"

Thanks for all the replies, I just re-read my post and realized I screwed up on the most critical word, I meant to say the the VSV's are NOT switching because the voltage is not changing. So that VSV's are not being told to switch.


Thanks
Ray

Odds are it´s a sender switch on the TC. While a leak on the relay would do it, the sender switch is the common fail. The VSV circuit only switches when the TC goes into 4x4 as signaled by the position switch, not because the button is pushed.

 

[TheDurk]

If your VSV's are working Ray, the next thing down the chain is the front diff.
The vacuum lines go to the vacuum actuator actually on the front diff.
Check the vacuum lines going down to your front end for splits, etc.

Possible the mechanism is seized in your front diff or simple as a hose pulled off the vacuum actuator down there.

There are guys who know this system that prowl around here and like you, I searched high and low for tips and ideas not being familiar with these systems.

I guess I would try to validate the integrity of your front diff now by applying vacuum to the front actuator (from under the truck, above the skid plate via whatever way you can eg: vacuum or very low air pressure (15-20 lbs).
Perhaps when you get in there you will see your problem.
You should be able to hear the front diff engaging and disengaging by applying vacuum directly to the bellows there.
Bellows is on the passenger side of the diff.

Not much help here I know but good luck.

Not his problem as it turns out, but the easy way to test the actuator is just switch the two diff hoses at the VSV when in 4x2, assuming one has vacuum. The front shaft should then lock, confirming the diff became engaged. Don't forget to switch back.

 

[Grenvilleter]

Have a look in this thread that TheDirk replied to in that explains how the whole system works together as a package.
With his explanation, you should be able to isolate where your problem is for certain and repair or at least isolate what component(s) are not functioning

http://www.toyota-4runner.org/3rd-gen-t4rs/130571-1997-4runner-4wd-issues.html

 

[rmoore]

TheDurk, Thanks for you help. I will take a look at the switches today and see what I can find. I will do a physical look first for something obvious the see if I can figure out how to test with a meter or something. I know from looking a diagram I found somewhere that there a few different switches on the Transfer case. I'll see if I can figure out where they and how to test.

Thanks
Ray

 

[FotoMaker]

I have a 97 SR5 5 speed with just a second stick for 4wd hi and low, no button. The 4wd will not engage and of course neither will the light on the dash.

We have determined that the propeller shaft engages but the front differential does not... Performed the vacuum switch test and the front wheels and light work properly.

The vacuum switches on and off on the blue side of the VSV/Solenoid with a shift change but the vacuum on the brown side is ALWAYS pulling, no matter the position of the shifter. The blue side vacuum tends to be weak.

Diagnosis is a stuck VSV/Solenoid... List price is $ 636.02.
The diaphragm is also suspected of bad health.

I welcome any input... Thanks!

Jeff

 

[FotoMaker]

Any opinions on my vacuum situation?
Is it most likely a stuck VSV or could it be something else?

Any news from the OP?

Where's The Durk?

 

[rmoore]

I just finished troubleshooting mine today, I found the 4WD Transfer Indicator Switch on the Transfer case was not closing when the transfer case switched into 4WD mode. This is the switch where the harness unplugs from the switch and is located next to the Transfer Case actuator motor assembly. All the diagrams indicated that there where two identical switches labeled Transfer Indicator 1 and 2, But mine only has one switch. Part number 84222-12010. I pulled the switch and checked it with a meter and it will not complete the circuit. I used the paperclip trick and shorted the wire harness side togather and started the engine and it engaged the 4WD selector switch and it went right in and the 4WD light came on. Thanks to TheDurk for all the troubleshooting tips.

On your problem, If your blue side is switching on and off that says your 12 volts are switching on and off on that Solenoid. If you put a volt meter on on the 12 volt supply of the brown solenoid and toggle the 4WD drive selector switch does it switch on and off also.
If it does not it would seem like an electrical switching problem or shorted solenoid, I would then pull the connector and check directly on the connector side for voltage change.
If it does, and you pull the longer hose that goes down to the front diff and actuator, does your vacuum go on and off on the output side of the Solenoid where the hose was plugged in?
If the vacuum switches there then I would think the solonoids is working and the problem is something leaking down on the front diff side.
If the voltage does switch and the vacuum does not switch at the Solenoid output side then it does sound like a bad solenoid.
I really do not know much about the circuits but this is just some of the things I was trying when looking at mine. There are a lot more knowledgeable people on this forum then me, hopefully someone will add some better advice.

Thanks
Ray

 

[rmoore]

Also for an FYI, I found that ROCKAUTO had the switch for $27.00 versus around $50 from other on line dealers. The part number was 600554 (600-554) and Labled Transfer Case Switch.

 

[TheDurk]

I have a 97 SR5 5 speed with just a second stick for 4wd hi and low, no button. The 4wd will not engage and of course neither will the light on the dash.

We have determined that the propeller shaft engages but the front differential does not... Performed the vacuum switch test and the front wheels and light work properly.

The vacuum switches on and off on the blue side of the VSV/Solenoid with a shift change but the vacuum on the brown side is ALWAYS pulling, no matter the position of the shifter. The blue side vacuum tends to be weak.

Diagnosis is a stuck VSV/Solenoid... List price is $ 636.02.
The diaphragm is also suspected of bad health.

I welcome any input... Thanks!

Jeff

Have you verified the electric signal to the brown side is switching off when the blue side vacuum is on? A 12V test light will get this answer. If it is, then bum VSV is the answer. Compare the resistance of the brown side with the blue if electric is switching. This will likely show a real difference if solenoid coil is shot. Otherwise it is mechanical valve problem.

I would expect blue side to be weak if brown side is always pulling. Plug the brown input to the VSV with a golf tee and I bet blue gets strong. EDIT: Just read rmoore's post-- I could have quoted him.

Try a junk yard or I bet there is a generic solution--I myself have never had to swap one. But it is such a simple function that I am sure a cheap fix is out there.

 

[FotoMaker]

Very helpful... I'll look into it... Thanks guys!

 

[FotoMaker]

Problem Resolved!

Turns out that the VSV was bad AND the Actuator was frozen.
I bought a used VSV on eBay for $35.00 and took it too my dealer to complete the diagnosis. Cost me $ 180.00 including replacing the VSV and freeing up the Actuator. The 4WD started working the day the snow melted.

 

[rmoore]

LOL, of course, That's the way it always goes.

Glad you have it working!!


Thanks
Ray

 

[FotoMaker]

We had some snow recently and it was sure nice having the 4wd working!

Now I just have to decide if I am going to take on the frame rust or sell her as a parts car... More fun!