? bad 4WD vacuum switch

Kernal

 
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Dec 10, 2007
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My 62 was stuck in 4WD, the green light wouldn't go out by pushing the dash button. I switched the front hoses on the vacuum switch, pushed the dash button, and the light went out.

Does this mean that the problem is all in the vacuum switch and I just need to replace it? I don't yet have a manual, is there a way to check it, clean it, fix it, or is it toast?
 

Ming89FJ62

I smell bacon
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You are correct in your diagnosis. The 2WD solenoid has died (redish brown one iirc). The OEM replacment is expensive - in the $300 range. Try using search for a cheaper fix w/ off the shelf pneumatic valves or just keep on swapping the vac hoses.
 

Kernal

 
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What actually does that solenoid or switch do (how does it do it) and what is happening when you switch the vacuum hoses? And how is all that related to the ?vacuum thingy on the side of the transfer case?
 
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I can not tell you much other than It has just happened to me and switching
the vacuum hoses worked , and the site has a lot of great info on an inexpensive fixes,
however you want to do it .. The oem part will make you want to throw up a little!!
I have replaced mine in a few minutes and was back in action !!
 

VTCruiser

 
 
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The switch simply sends voltage to either the "on" (4WD) solenoid, or the "off" (2WD) solenoid. The solenoids are activated by voltage from the switch, and control the vacuum to the transfer case shifting mechanism. In simple terms, when the 4WD solenoid is powered, it pulls a pin to engage the 4WD. When the 2WD solenoid is powered, it pulls the pin back out to disengage.

The switch (the button in the dash) appears to be fine, but you can check with the voltage to be sure. Chances are you've got a bad 2WD solenoid. In the FAQ there is a thread about a cheap ($18) solenoid replacement. I used two to build my own assembly when I converter to 12V:

FAQ: https://forum.ih8mud.com/60-series-wagons/224061-writeup-1988-fj62-4wd-solenoid-fix-$17-77-a.html

 
Last edited:

Kernal

 
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Dec 10, 2007
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Ok, I think I got it. The bottom VSV with the red connector is the bad piece. I can either replace that with new, used, or get the alternate VSV and make it fit; correct? Any problem with just leaving it as is for now, I rarely use 4WD with this rig.
 
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Until you want to replace it you can suck on the tube yourself and create the vacuum needed to get it out of 4WD. Therefore you theoretically don't need the red VSV if you shoose to do it manually. Then to get into 4WD you just press the button as the top blue VSV works fine.

You don't necessarily need to do anything. Right now you are wasting gas when you drive it becauase the front driveshaft is in 4WD but the hubs aren't engaged. Like you said, if you rarely drive it you're ok. Thankfully the blue one doesn't fail and leave people stranded without 4WD.

pm me if you have any questions. I did the write up that VTCruiser linked you to.
 
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Nov 22, 2007
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Buxton Me
depending on where you live it might be in the line to the transfer case. reason being my buddy had the same problem would not go into 4whl but was getting all the switches to work ended up being bad line the metal part in line rusted out. Thankfully we had a parts truck with the right part so he got out of it cheap for now.
 

VTCruiser

 
 
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There is a procedure in the FSM, but basically you can just turn the engine on, push the switch to 4WD, and unplug the vacuum from the VSV input. You should feel the vacuum with your finger. If not, there is a faulty line upstream of the solenoid. If there is vacuum, plug the input back in, unplug the output, and see there's any vacuum. If not, make sure the solenoid is getting voltage. If it has power but no vacuum output, it's faulty. If you have a friend, he can turn the switch off and on, and you should feel the vacuum come and go, you may even feel or hear the solenoid click as well. If the VSV is functioning properly, you have a plugged or leaking line between it and the t-case.
 
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The switch simply sends voltage to either the "on" (4WD) solenoid, or the "off" (2WD) solenoid. The solenoids are activated by voltage from the switch, and control the vacuum to the transfer case shifting mechanism. In simple terms, when the 4WD solenoid is powered, it pulls a pin to engage the 4WD. When the 2WD solenoid is powered, it pulls the pin back out to disengage.

The switch (the button in the dash) appears to be fine, but you can check with the voltage to be sure. Chances are you've got a bad 2WD solenoid. In the FAQ there is a thread about a cheap ($18) solenoid replacement. I used two to build my own assembly when I converter to 12V:

FAQ: https://forum.ih8mud.com/60-series-wagons/224061-writeup-1988-fj62-4wd-solenoid-fix-$17-77-a.html

I am having this same issue. i ordered the cheaper part off the 88 Toyota pick up, however, i seem to have another issue. The PO had replaced this before with an aftermarket VSV that didn't share the same electrical wire housing, so he clipped the wires and put female ends on each of the wires to attach to his aftermarket VSV. So my dilemma is how to connect the electrical wires to my Toyota VSV part without the original male connector? I guess i could just put smaller female adapters on the wires and slide them into connector on my part or is their a way i can order the red male wire adapter? Or search for a junker that has this part available...hmmm
 

Crick60

Mr Crick
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Sep 7, 2010
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951
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Australia
Also that connector is still available from component stores quite readily, to really fix it get a new one and get the store to terminate it for you or get a wrecked one and solder the wires with a bit of tail so you have room to work.
 
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