Low range 2 wheel drive
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Posting Guru
Joined: Jul 2008
Posts: 1,302
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From: Morehead, Ky.
Low range 2 wheel drive
Hey guys, I am ready to put in a switch to cut out the pulse relay for the ESOF when in low range. Does it matter which of the three wires I cut and run through the switch? Thanks to all Jim
Lead Driver
Joined: Sep 2007
Posts: 8,180
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From: Scio, OR
Light blue with pink stripe is power when the key is in run. Grey with black stripe is grounded to engage the hubs, red is grounded to disengage the hubs.
I think I would break the engagement wire. That way the hubs would always attempt to disengage, regardless of your switch.
I think I would break the engagement wire. That way the hubs would always attempt to disengage, regardless of your switch.
Lead Driver
Joined: Sep 2007
Posts: 8,180
Likes: 669
From: Scio, OR
Passenger side firewall, above the vacuum reservoir. It's a small unit with a 3 wire connector and two vacuum hoses. I have a picture around here somewhere, I'll see if I can find it.
Edit: Didn't have one, so I went and took one.
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Edit: Didn't have one, so I went and took one.
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Hook it, I'll pull it.
Joined: May 2007
Posts: 15,037
Likes: 4
From: Grand Lake, La.
If you don't want to go through the trouble of doing the switch thingy, you can always just unplug the connection on the sensor and it will not send the pulse to lock the hubs. This is what I do when I have to back a trailer up an incline. I don't do it much, so no need for the switch for me. 
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FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
Dave, are you sure you want to cut just the engagement side of things? A low-vacuum short pulse (20 seconds) is still applied for disengage, and I'd be worried that if the hubs are free-moving enough that they may lock instead of staying disengaged.
I had a situation once with my '01 that one of the hubs was working opposite, in that it was locked when I was in 2-wheel drive, and UNLOCKED when in 4-wheel drive.
I had to shut the truck down with the **** in 4x4, turn it to 4x2 with the key off, and restart, and it cleared up.
So, wouldn't it be best to cut the common and never have to worry about it?
I had a situation once with my '01 that one of the hubs was working opposite, in that it was locked when I was in 2-wheel drive, and UNLOCKED when in 4-wheel drive.
I had to shut the truck down with the **** in 4x4, turn it to 4x2 with the key off, and restart, and it cleared up.
So, wouldn't it be best to cut the common and never have to worry about it?
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Lead Driver
Joined: Sep 2007
Posts: 8,180
Likes: 669
From: Scio, OR
Dave, are you sure you want to cut just the engagement side of things? A low-vacuum short pulse (20 seconds) is still applied for disengage, and I'd be worried that if the hubs are free-moving enough that they may lock instead of staying disengaged.
I had a situation once with my '01 that one of the hubs was working opposite, in that it was locked when I was in 2-wheel drive, and UNLOCKED when in 4-wheel drive.
I had to shut the truck down with the **** in 4x4, turn it to 4x2 with the key off, and restart, and it cleared up.
So, wouldn't it be best to cut the common and never have to worry about it?
I had a situation once with my '01 that one of the hubs was working opposite, in that it was locked when I was in 2-wheel drive, and UNLOCKED when in 4-wheel drive.
I had to shut the truck down with the **** in 4x4, turn it to 4x2 with the key off, and restart, and it cleared up.
So, wouldn't it be best to cut the common and never have to worry about it?
Edit: OK, this probably wouldn't work either, since F2.27 is one of the main switched power feeds and probably runs quite a few things other than the PVH solenoid. Now, you could still run a wire from an upfitter switch, into the engine bay, and either hook it directly to the center PVH solenoid wire and operate it like I described first, of use a relay to get an opposite result. If that makes any sense.
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Cargo Master
Joined: Apr 2006
Posts: 3,215
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From: WV
I still haven't got around to this mod yet... its on the list though.
