Help Diagnose ESOF

slee22 · Feb 8, 2012

My 4WD only works when the hubs are locked, which I know could be a vacuum problem, but the A/C works fine and never switches to defrost.
When I turn the ESOF switch, I can here the t-case solenoid and the 4x4 light comes on, but I don't here the hubs engage or any clicks from the solenoid on the passenger side (I'm plannning on replacing the vac lines to the hubs this weekend).
Also, there is a line from the black box behind the passenger battery that's unhooked and I'm not sure what it is.
Here's a pic:

Thanks

Zmann · Feb 8, 2012

that device at the lower right
of the pic with the wiring plug is the ESOF actuator

it gets a signal from the PCM and will direct a varied vacuum signal to the hubs telling them to lock or unlock the duration is short so it's a litle tricky to test by yourself

mine had failed but it should have two vac lines going in to it ,, check that

Zmann · Feb 8, 2012

the best way to trouble shoot these is with a vacuum tester like a mighty vac

Zmann · Feb 8, 2012

ps I just checked the red line is one of the two that goes to the solenoid

slee22 · Feb 8, 2012

Ok my red line is plugged in to the solenoid. Is the one circled in the pic supposed to be open?

Zmann · Feb 8, 2012

ah I missed that the pic is a little hard to see whats what and going where

it might be the other one that goes to the solenoid and supplies the vacuum should be a total of two going to that solenoid are you sure no one replaced your hubs with mechanical only ?

the end of those vac lines has a fitting that IIRC only lets you put those two on the solenoid one way

that big canister is the vacuum reservoir

slee22 · Feb 8, 2012

Yeah sorry for the crappy cellphone pic. I've got the red line (which goes into a "T" and into the vacuum res) and the one covered in wire loom going into the solenoid. Then there's short line coming out of the vacuum res (circled) is that for air bleed off maybe? I'm trying to cover my bases and make sure nothing is disconnected before replacing vacuum lines. It's still got OEM auto hubs, and they turn easily by hand.

Zmann · Feb 8, 2012

give me a few I will snap a pic

hope it turns out better than yours cough

Zmann · Feb 8, 2012

ok there is one from the vac pump that goes to the reservoir

the other part of that fitting on the reservoir from the reservoir is the red line to the solenoid so those all supply vacuum

the other line from the solenoid goes to the hubs

slee22 · Feb 8, 2012

Ok, I wonder if my truck being an Ex is different (since my lines don't look like yours or any other pics I've searched for). I've got a different line going into the pump, the black line out of the reservoir isn't connected at all, and nothing's connected to other side of the red line's "T".

Zmann · Feb 8, 2012

ah ,, maybe different mines an 06

but basically I think someone bypassed your reservoir and ran the feed to the HVAC directly out of the pump

Zmann · Feb 8, 2012

the other side of the red line Tee on mine feeds down to the HVAC on the other side of the firewall I think

if you need some more pics just ask but I don't think these have changed much besides the added heater bypass vacuum valve for MAX AC

slee22 · Feb 8, 2012

If I have some time tomorrow or so, I'll chase down the lines and see if I can figure out where they go...hopefully its not bypassed, but the previous owner did some stupid sh*t to the truck like install some piecemeal lift that felt like it about to break apart at any minute.

Zmann · Feb 8, 2012

I think He jacked this also ,, the resevoir might have a crack ,, no worries just keep on it

and did u make sure you still have Warn auto capable hubs ?

otherwise this is a waste of time

slee22 · Feb 8, 2012

Yeah I have OEM Auto hubs, and they turn easily by hand.

Zmann · Feb 8, 2012

cool just checking

slee22 · Feb 9, 2012

Ok I chased the lines and they're all connected to something aside from the "T" on the red line and the short black line coming from the vacuum reservoir.
Pic:

Edit: I'm wondering if the "T" on the red line should connect to the HVAC (instead of the black line that's connecting to the pump in my pic) and the broken line should connect the reservoir to the pump. At least that's what it kinda looks like in your pic.

Zmann · Feb 9, 2012

in your picture

black line that goes to HVAC should go to the red t not the pump

the broken open line should loop to the pump to supply vacuum I bet your pump cycles strange without the extra volume ?

I think the resevoir might be cracked and this was the hill billy fix ??