94 4runner 4wd not doing anything

C

colep123

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Of course since we got some snow I tried putting my 4runner into 4wd. It doesn't do anything. No lights in dash, no clicks or dings. It worked last time I went to use it earlier in the summer. I did have some vacuum hoses replaced by a mechanic this summer as well.

It is an automatic 3.0
 
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colep123 said:
Of course since we got some snow I tried putting my 4runner into 4wd. It doesn't do anything. No lights in dash, no clicks or dings. It worked last time I went to use it earlier in the summer. I did have some vacuum hoses replaced by a mechanic this summer as well.

It is an automatic 3.0
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Check the two vacuum hoses that activate the ADD.
 
colep123 said:
thank ill start there. could it just be simply switching how they are currently hooked up?
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Two vacuum hoses - one to activate, one to deactivate. Just make sure they are connect properly. When I bought my 4Runner - for some odd reason - the PO had pulled the hoses from the diff. Once I hooked them back up - 4WD!
 
well before I messed with the hoses I tried the 4wd 1 more time since I was in a snowy parking lot and what do you know, it ENGAGED! :girl: I am not sure if the hoses were frozen or what. The 4runner did sit out yesterday in the nice warm sun for the entire day.
 
colep123 said:
well before I messed with the hoses I tried the 4wd 1 more time since I was in a snowy parking lot and what do you know, it ENGAGED! :girl: I am not sure if the hoses were frozen or what. The 4runner did sit out yesterday in the nice warm sun for the entire day.
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When was the last time you changed your diff/transfer case fluids? Could have some water in there.

:keyboard:
 
def a vacuum thing going on. Tried the 4wd again last night and it didn't engage. Played with a few of the hoses and it engaged then disengaged on its own
 
The solenoids (actually called Vacuum Switching Valves) can go bad but it doesn't sound like that's your problem since they were working for you the other month. If one of them is passing vacuum in 2wd and the other passes vacuum in 4wd, your problem is not the VSVs. If neither of them passes vacuum you can check the plugs to see if one is getting power (same deal, they'll switch power in 2wd/4wd). If you have power to either one and still no vaccum, you have a vaccum leak or a clogged filter (between the VSVs and the engine). What were you messing with when it engaged/disengaged on its own? Were you able to repeat it or could it have just been coincidental?

It's more likely that you have a loose electrical connection or ground somewhere since you were getting no response from shifting into 4wd (no power at the VSVs would confirm this). If your 4wd system is malfunctioning you should be getting flashing lights (can't say for sure because I don't know how much your system differs from my 00 limited).
 
Thanks for the reply.

When I was able to get it to engage, I simply had just wiggled and pushed all of the hoses/electrical connectors at the VSV. It would engage, then quickly disengage. I cannot get this to repeat now! I will clean the connectors at the VSV and see what that does, even though it looks relatively clean.

Ill keep tracing hoses. Whoever owned this before me has hoses connected, and disconnected and cut all over the place. Mostly they just left stuff in there with out cleaning it out!
 
Sounds like PO did you no favors... a full once over on the entire 4WD system is needed; starting with vacuum lines.
When I first got mine the 4WD didn't work. The two vacuum lines at the diff actuator were backwards.
 
I was messing around with lines.
I engaged and disengaged the 4wd. I did hear a click but nothing. I un hooked these lines and what sounded like compressed air came out of the top 2 after I had turned the truck off and took the hoses off

 
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The top two lines should always have vacuum, they're the source line. If you heard the click in the the area of those vacuum lines when 4wd was engaged, you were hearing the VSV activate which opens it up to pass vacuum from the source lines to the front diff ( bottom 2 vacuum lines).

Just to be clear, your vacuum lines aren't reversed so don't go reversing them now. I can see from the pic that the blue line is going to the blue VSV.
 
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When I heard the "click" it was just once, then when I went to engage again, nothing. Hole in a vacuum line?

Ill start here and follow these lines...... of course it snowed here is CO last night and is about 15 degrees out! Ill take a look this weekend when it warms up!
 
So I found some time and weather to mess around with this. I replaced the ADD solenoids and checked vacuum lines. I got the 4wd to engage while in Drive, but once shifted into neutral or reverse, the 4wd disengages. Pop it back into Drive, and the 4wd is engaged. Any thoughts?
 
We looked again at it last night, reduced it down to something electrical. Mechanic friend thinks its a neutral safety switch. He thinks its the one on the back left of the tranny. Will keep updated once we figure it out
 
The solenoid that controls the disengage has a consistent vacuum to it through all gears including park, and then the engage solenoid only has the vacuum in "Drive".
 
Check your wire going to your actuator. Maybe even remove it and use a multimeter to test for connectivity. Its a simple job, mine gave me problems and from what I understand that's what lights up the dash 4wd light.
 
I found a connector last night while we had it on the lift replacing the rear springs that wasn't plugged in. Plugged it in and it seems like its going into 4wd. I goes into 4 low for sure, can physically feel it. The light on the dash will flash twice and go out, and then flicker here and there, but every time I shifted into 4wd the light would give an indication.

next step will be the wires coming off of the actuator. We looked at them last night and physically they looked in good working function, but will either replace the entire actuator or check the connectivity.
 
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