4hi Does not engage but 4Lo works

[scrap metal]

Trying to tackle this problem.

2000 4runner v6 5spd manual.

Vehicle engages into 4lo.
Will not engage into 4hi.
I swapped vacuum lines from the 2hi vsv onto the 4wd vsv and was able to get into 4hi with that method.

4hi position switch at Transfer case is operational.

What's left? 4wd ecu? Is there a separate relay for 4hi and 4lo??

 

[Doc2012]

You just answered your own question...........


"swapped vacuum lines from the 2hi onto the 4wd vsv and was able to get it into 4hi with that method."

Get a new vsv.

 

[TheDurk]

You just answered your own question...........


"swapped vacuum lines from the 2hi onto the 4wd vsv and was able to get it into 4hi with that method."

Get a new vsv.

No, I don't think so. If 4L engages the ADD, then VSV is working. Should really confirm with test light or meter that electric signal to the solenoid is not switching sides when 4H engages and then 100% sure it is NOT VSV.

At this point, I'd have to say the symptom set points to the wiring between the 4H switch and the VSV, in fact just between the 4H switch and the ADD control relay, which, ON A 5-SPEED, is just a simple relay and lives in the RIGHT kick panel. Happily, no 4wd ECU to mess with. (I have the same rig, 1999 version.)

So, to nail this down:

1) Does the blue 4wd VSV have 12V+ and good ground when 4H engaged? If not, does the brown?
2) Does the ADD relay in the right kick panel have good ground at Pin 2 (blue wire) with 4H engaged. (This relay has five wires on a 6-pin connector: blue, light green, green/red and 2 black/whites.) Then try it in 4L just to confirm we are doing this right.

How did you test 4H switch on TC? Did it have a white/black wire and a blue wire?
How did you confirm 4L engaged?
Do you have rear e-locker (rare on a 5-speed)?

 

[scrap metal]

-I know vsv works since I can get into 4lo and dash light comes on. I've been off roading this way for a while now so i know it's actually in 4x4, but I figured it's time to fix it.

-4hi switch at transfer case
I removed the switch and when pressed in it ohmed out at 5 ohms. I replaced with another switch that ohmed out at 0 ohms and still no light/4hi.

- thanks! I'll check out the relay now!

P.S. I have rear diff lock but I swapped it in from one of my previous 4runners... I have yet to wire it haha.

 

[Doc2012]

Sorry for the mislead [MENTION=96948]scrap metal[/MENTION].

Sounded like swapping out the VSV worked for you, so that seemed like the best answer.
[MENTION=10169]TheDurk[/MENTION]


This is why I got rid of all that shit.

Too much crap to go wrong.

Do the manual hub swap, and convert the diff to the manual by locking the sleeve in place.

 

[scrap metal]

-4wd vsv gets +12v when in 4lo. Not 4hi.

- Transmission relay clicks closed in 4lo not 4hi.

-I went back to the 4hi transfer case switch and jumped the wires (bypassing switch) and still no relay click or engagement.

Do you have a wiring diagram for the transmission relay?
I wonder if I have an actual wiring problem.

I'm thinking of hijacking the 4lo wires and also connecTing them to the 4hi switch.

 

[TheDurk]

-4wd vsv gets +12v when in 4lo. Not 4hi.

- Transmission relay clicks closed in 4lo not 4hi.

-I went back to the 4hi transfer case switch and jumped the wires (bypassing switch) and still no relay click or engagement.

Do you have a wiring diagram for the transmission relay?
I wonder if I have an actual wiring problem.

I'm thinking of hijacking the 4lo wires and also connecTing them to the 4hi switch.

Looks like wiring to me. I would:

1) Jump ground to that blue wire Pin 2 (OOPS, blue is on 2 not 4!!) on the relay with 4H engaged.
2) If relay engages, run a by-pass from blue wire on TC switch to Pin 4 on relay and see if THAT engages.
3) If so, we start tracing that blue wire from TC to relay until we find the fault. It would appear that it has to be in the first leg, between the TC 4H switch and the I11 connector where the 4L signal comes in. I11 is a ten pin dark grey connector behind the glove box.

The issue with your cross connect idea is that you would trigger whatever morph the ECU does when 4L is called when you are only in 4H. I have no idea what the ECU does in 4L, but it probably limits you somehow. I assume it disables ABS, but I don't know if it limits revs or something as well.

Take a close look at your connector on your 4H TC switch. Hit it with contact cleaner and compressed air. I bet the issue is right there. Test continuity from blue wire on TC to Pin 2 on the relay before and after cleaning.

 

[scrap metal]

Awesome. The schematic is a huge help! I still think its a wiring problem since I jumped the blue to the ground at the transfer case and still nothing.

I will go investigate some more

 

[scrap metal]

PROBLEM SOLVED!

I should slap the previous owner/mechanic. I further investigated the wiring and found out nothing made sense. I went back under and verified ground was good. Then I learned the "blue" wire was getting 10-11v which made no sense since it was not continuous at the relay. I went back with a flashlight and some cleaner...

the blue wire turned into a blue red wire.

PLUGS WERE SWITCHED! the 4lo plug was plugged into the 4hi switch and vice versa. switched them and Now it all works.

 

[TheDurk]

PROBLEM SOLVED!

I should slap the previous owner/mechanic. I further investigated the wiring and found out nothing made sense. I went back under and verified ground was good. Then I learned the "blue" wire was getting 10-11v which made no sense since it was not continuous at the relay. I went back with a flashlight and some cleaner...

the blue wire turned into a blue red wire.

PLUGS WERE SWITCHED! the 4lo plug was plugged into the 4hi switch and vice versa. switched them and Now it all works.

Well, I SAID the problem was at the connector! Didn't see that coming, though....Aren't the two halves of the connectors colored? So he had them both two-tone?