ESOF
#1
10-05-2011, 02:41 PM
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ESOF
I have ESOF issue. Auto 4X4, defrost comes on. Lock 4X4, works fine. I found the vacuum leak. It's coming from the little vac hose that comes from the solenoid and into a little nipple that goes straight down to the wheels. I was able to plug the bottom vac hose into the solenoid (bottom) and hook up a small hose from the solenoid (top) to the wheel vac line. Now the fan does not go into the defrost when I turn the **** in 4X4. But the truck does not go into 4X4. Now what?
I hope I am clean on what's going on?
I hope I am clean on what's going on?
#2
10-05-2011, 02:55 PM
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#3
10-07-2011, 11:20 AM
Found this info on the electrical side of the ESOF but you've prob seen it allready:
#4 (permalink) 07-21-2011, 05:08 PM
dchamberlain
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Location: Lake County, Oregon
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I'm assuming your 4WD isn't working, and that the 4x4 light on the dash is not coming on when you switch the switch to 4WD.
First thing to do is to check the make sure the 4x4 light is working. It should come on briefly when you start the truck. If it does then you know the light is working at least.
Find and check fuse #19, 27, 31, 33, 34, 45 and 111. Don't just visually inspect them, take them out and check them for continuity between the pins with a meter.
Get an assistant, get under the truck with a standard test light and find the 2 pin connector to the transfer case shift motor. Unplug that connector and connect the test light between the two pins of the connector. With the key in the RUN position (the engine doesn't actually have to be running), have your assistant turn the **** to 4WD. The test light should flash a number of times as the 4WD module tries to engage the shift motor.
IF the light flashes, then everything upstream of the shift motor is working. Inspect the connector, and the plug on the shift motor it connects to for any sort of corrosion or indication that there might be a bad connection. If everything looks good the shift motor is probably bad and needs replaced.
If the light does not flash then you need to find out why. The next most likely problem is one of the transfer case shift relays. The shift relays will be in a auxiliary relay box under the hood, drivers side towards the rear of the vehicle. They are usually in a relay box by themselves. Two identical relays with nothing else in the box. The box is wrapped from the factory with fabric electrical tape, but that might be gone if someone has already opened it. First thing to do is remove the relays and look for corrosion. If you find corrosion, clean it up good and try again. If that doesn't work, continue to the next step.
A good test of the relays is two remove them and swap their positions. One of the relays is used to turn the shift motor from the 2WD position, to the 4WD position, and then to the 4Low position. The other relay turns the motor back the opposite direction, from 4Low, back to 4WD, then back to 2WD.
When the relays are swapped, try shifting into 4WD again. If it works, you've found a bad relay and should probably just change them both.
If none of this works, then we'll need to look at the relay base wiring for corrosion and possibly move on to the 4WD control module.
__________________
David Chamberlain
2004 F-250 SD, 4x4 FX4, 6.0L PSD
I guess the fan is running but no airflow out of the defrost?
#4 (permalink) 07-21-2011, 05:08 PM
dchamberlain
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Garage is empty, add now Join Date: Sep 2007
Location: Lake County, Oregon
Posts: 4,134
I'm assuming your 4WD isn't working, and that the 4x4 light on the dash is not coming on when you switch the switch to 4WD.
First thing to do is to check the make sure the 4x4 light is working. It should come on briefly when you start the truck. If it does then you know the light is working at least.
Find and check fuse #19, 27, 31, 33, 34, 45 and 111. Don't just visually inspect them, take them out and check them for continuity between the pins with a meter.
Get an assistant, get under the truck with a standard test light and find the 2 pin connector to the transfer case shift motor. Unplug that connector and connect the test light between the two pins of the connector. With the key in the RUN position (the engine doesn't actually have to be running), have your assistant turn the **** to 4WD. The test light should flash a number of times as the 4WD module tries to engage the shift motor.
IF the light flashes, then everything upstream of the shift motor is working. Inspect the connector, and the plug on the shift motor it connects to for any sort of corrosion or indication that there might be a bad connection. If everything looks good the shift motor is probably bad and needs replaced.
If the light does not flash then you need to find out why. The next most likely problem is one of the transfer case shift relays. The shift relays will be in a auxiliary relay box under the hood, drivers side towards the rear of the vehicle. They are usually in a relay box by themselves. Two identical relays with nothing else in the box. The box is wrapped from the factory with fabric electrical tape, but that might be gone if someone has already opened it. First thing to do is remove the relays and look for corrosion. If you find corrosion, clean it up good and try again. If that doesn't work, continue to the next step.
A good test of the relays is two remove them and swap their positions. One of the relays is used to turn the shift motor from the 2WD position, to the 4WD position, and then to the 4Low position. The other relay turns the motor back the opposite direction, from 4Low, back to 4WD, then back to 2WD.
When the relays are swapped, try shifting into 4WD again. If it works, you've found a bad relay and should probably just change them both.
If none of this works, then we'll need to look at the relay base wiring for corrosion and possibly move on to the 4WD control module.
__________________
David Chamberlain
2004 F-250 SD, 4x4 FX4, 6.0L PSD
I guess the fan is running but no airflow out of the defrost?
#4
10-07-2011, 12:41 PM
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#5
10-07-2011, 01:19 PM
So your problem is in the vacuum hublock system.
I'm assuming that your heater and a/c are all working correctly? If so, then you either have a vacuum leak in the solenoid or after it. If you can get a hand vacuum pump and gauge, hook everything back up like it should and start by hooking the pump/gauge to the hub nipple itself. Pull down a vacuum and see if it holds. Do this on both hubs.
If a hub won't hold a vacuum then it needs new seals. If it will, reconnect the lines and move up to the next junction and do the same thing. As soon as you get to a point where it won't hold a vacuum, you've found the leak. If you never find one, then it is probably a failed solenoid.
Also, use a test light or DVOM and measure the voltage on the center wire to the solenoid. There should be 12V there with the key in RUN.
I'm assuming that your heater and a/c are all working correctly? If so, then you either have a vacuum leak in the solenoid or after it. If you can get a hand vacuum pump and gauge, hook everything back up like it should and start by hooking the pump/gauge to the hub nipple itself. Pull down a vacuum and see if it holds. Do this on both hubs.
If a hub won't hold a vacuum then it needs new seals. If it will, reconnect the lines and move up to the next junction and do the same thing. As soon as you get to a point where it won't hold a vacuum, you've found the leak. If you never find one, then it is probably a failed solenoid.
Also, use a test light or DVOM and measure the voltage on the center wire to the solenoid. There should be 12V there with the key in RUN.
#6
10-07-2011, 01:33 PM
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So your problem is in the vacuum hublock system.
I'm assuming that your heater and a/c are all working correctly? If so, then you either have a vacuum leak in the solenoid or after it. If you can get a hand vacuum pump and gauge, hook everything back up like it should and start by hooking the pump/gauge to the hub nipple itself. Pull down a vacuum and see if it holds. Do this on both hubs.
If a hub won't hold a vacuum then it needs new seals. If it will, reconnect the lines and move up to the next junction and do the same thing. As soon as you get to a point where it won't hold a vacuum, you've found the leak. If you never find one, then it is probably a failed solenoid.
Also, use a test light or DVOM and measure the voltage on the center wire to the solenoid. There should be 12V there with the key in RUN.
I'm assuming that your heater and a/c are all working correctly? If so, then you either have a vacuum leak in the solenoid or after it. If you can get a hand vacuum pump and gauge, hook everything back up like it should and start by hooking the pump/gauge to the hub nipple itself. Pull down a vacuum and see if it holds. Do this on both hubs.
If a hub won't hold a vacuum then it needs new seals. If it will, reconnect the lines and move up to the next junction and do the same thing. As soon as you get to a point where it won't hold a vacuum, you've found the leak. If you never find one, then it is probably a failed solenoid.
Also, use a test light or DVOM and measure the voltage on the center wire to the solenoid. There should be 12V there with the key in RUN.
#7
10-07-2011, 05:53 PM
2004 F250 ESOF Hub Service
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#8
10-07-2011, 08:57 PM
John, here's a portion of the writeup from the Ford Workshop Manual, regarding how the Pulse Vacuum Hubs operate:
Hopefully, this should help give you a clear understanding of how they operate.
If you want to try a redneck method for checking the engagement of each hub, you can do so by having both wheels off the ground and sucking on a rubber hose attached to the nipple on each steering knuckle, while spinning the wheel by hand. If doing so fails to engage the axle, THAT is your problem.
Originally Posted by Ford Workshop Manual Section 308-07A
Hublock Operation
With the hublocks in the AUTO position, the 4WD ESOF system uses timed vacuum sequences to lock and unlock the wheel ends when switching the instrument panel MSS between 2WD and 4x4 modes. A high vacuum level (222 mm [8.75 in] Hg and greater) is applied to the hublocks to lock the internal spring mechanism that engages (locks) the hublocks for 4x4 mode, and a lower vacuum level (114 to 184 mm [5.9 to 7.1 in] Hg) is applied to unlock the spring mechanism that disengages (unlocks) the hublocks for 2WD mode. The vacuum signals are supplied to the hublocks by system components, including the 4X4 control module, wiring harness, solenoid, vacuum harness and vacuum seals. As a first step in service, eliminate obvious items such as loose wiring connections, loose vacuum connections or damaged vacuum lines.
Hublock Engagement/Disengagement Time
With the hublock dials in the AUTO position, switching the instrument panel MSS to 4x4 HIGH or 4x4 LOW results in the high vacuum level being applied to the hublocks, which lasts for at least 51 seconds (including a venting cycle). The hublocks should engage during this time through the spring mechanism. Switching the MSS to 2WD less than 51 seconds after the MSS has been switched to 4x4 HIGH or 4x4 LOW will not interrupt the high vacuum level; instead, the lower vacuum level will be applied after the high vacuum level cycle is completed.
With the hublock dials in the AUTO position, switching the MSS to 2WD results in the lower vacuum level being applied to the hublocks, which lasts for about 15 seconds. However, the actual time required for the hublocks to disengage by spring force can vary considerably due to the effects of driveline wind-up. Road bumps, vehicle speed, acceleration cycles or momentary reversal of direction can assist this process. Switching the MSS to 4x4 HIGH or 4x4 LOW always overrides the lower vacuum level cycle and results in an immediate high vacuum level and in locking of the hublocks.
With the hublocks in the AUTO position, the 4WD ESOF system uses timed vacuum sequences to lock and unlock the wheel ends when switching the instrument panel MSS between 2WD and 4x4 modes. A high vacuum level (222 mm [8.75 in] Hg and greater) is applied to the hublocks to lock the internal spring mechanism that engages (locks) the hublocks for 4x4 mode, and a lower vacuum level (114 to 184 mm [5.9 to 7.1 in] Hg) is applied to unlock the spring mechanism that disengages (unlocks) the hublocks for 2WD mode. The vacuum signals are supplied to the hublocks by system components, including the 4X4 control module, wiring harness, solenoid, vacuum harness and vacuum seals. As a first step in service, eliminate obvious items such as loose wiring connections, loose vacuum connections or damaged vacuum lines.
Hublock Engagement/Disengagement Time
With the hublock dials in the AUTO position, switching the instrument panel MSS to 4x4 HIGH or 4x4 LOW results in the high vacuum level being applied to the hublocks, which lasts for at least 51 seconds (including a venting cycle). The hublocks should engage during this time through the spring mechanism. Switching the MSS to 2WD less than 51 seconds after the MSS has been switched to 4x4 HIGH or 4x4 LOW will not interrupt the high vacuum level; instead, the lower vacuum level will be applied after the high vacuum level cycle is completed.
With the hublock dials in the AUTO position, switching the MSS to 2WD results in the lower vacuum level being applied to the hublocks, which lasts for about 15 seconds. However, the actual time required for the hublocks to disengage by spring force can vary considerably due to the effects of driveline wind-up. Road bumps, vehicle speed, acceleration cycles or momentary reversal of direction can assist this process. Switching the MSS to 4x4 HIGH or 4x4 LOW always overrides the lower vacuum level cycle and results in an immediate high vacuum level and in locking of the hublocks.
If you want to try a redneck method for checking the engagement of each hub, you can do so by having both wheels off the ground and sucking on a rubber hose attached to the nipple on each steering knuckle, while spinning the wheel by hand. If doing so fails to engage the axle, THAT is your problem.
#10
10-08-2011, 11:33 PM
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#11
10-11-2011, 02:20 PM
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Mike you just saved me from spending $$$. That worked. Who new that sucking on a hose could be $$ saved. After doing it on each wheel with good results, I directly hooked up a hose from each wheel to the vacuum solenoid and it would not engage. Now trying to get a part number.
Thanks Mike
Thanks Mike
#12
10-11-2011, 02:22 PM
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#13
10-11-2011, 02:24 PM
Mike you just saved me from spending $$$. That worked. Who new that sucking on a hose could be $$ saved. After doing it on each wheel with good results, I directly hooked up a hose from each wheel to the vacuum solenoid and it would not engage. Now trying to get a part number.
Thanks Mike
Thanks Mike
#14
10-11-2011, 02:33 PM
Okay, if it is the PVH solenoid you are trying to get a part number for, it is 7C3Z-9H465-A.
If you want to try another test, backprobe the outer two wires of the three wire connector on the solenoid with the ignition key in the RUN position, and connect the other end to the passenger side battery negative post. You should hear strong CLICKS when you do this. If they are faint, then the solenoid is weak.
If you want to try another test, backprobe the outer two wires of the three wire connector on the solenoid with the ignition key in the RUN position, and connect the other end to the passenger side battery negative post. You should hear strong CLICKS when you do this. If they are faint, then the solenoid is weak.
#15
10-11-2011, 02:56 PM
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