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How to Troubleshoot and Fix F150 4X4 1997-2003

1997 - 2003 F150 1997-2003 F150, 1997-1999 F250LD, 7700 & 2004 F150 Heritage
Old 11-18-2014, 04:52 PM
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How to Troubleshoot and Fix F150 4X4 1997-2003

Old 05-21-2018, 01:05 AM
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Originally Posted by revytrucks View Post
I am posting this because it took me AGES to find this information and peice it together from many sources all over the internet. From a girl who knew NOTHING about these systems a few weeks ago - here is a quick and easy guide to troubleshooting your 4X4 problems -- mostly for Manual shift on the floor (MSOF) systems or what goes on mechanically after you press the button on the electronic systems. All you need for these tests is a friend, and a socket set.

The 4X4 works with two systems - the shifter on the floor manually engages the transfer case. It also causes a relay to ground one of two solenoids that cause vacuum lines to activate an actuator which engages the front differential. If either of these do not work, your 4X4 won't work.

In my case, ad most that I have read, the 4X4 simply does not engage and the dash light either always goes on or does not go on.

1. Rule out transfer case problems: This is easy - get someone to put your truck in 4X4 and roll forward while you peek underneath from the side. If the front drive shaft is turning, your transfer case is fine and engaged.

2. Check the fuse! #23 by the hood lever and parking brake under the front dash.

3. Check the functioning of the solenoids: this is easy as well. The solenoids are located in the passenger side of the engine compartment directly behind the battery on the firewall.

From what I have read, a good indication of a problem here is the absence of the dash light. You can get fancy and test them electrically (they should each have 12V power all of the time) but the easiest way is to put your fingers on the plastic caps and feel and listen for a click as someone shifts your truck in and out of 4X4. If they click - they are working! If not, this is likely your problem. It is a common problem apparently for these years of trucks to get water in the solenoids which then freezes and cracks them.
Here is some good info and part numbers if this is your problem
"The right solenoid (E8AE-9H465-AA) controls the vacuum to the return side of axle engagement diaphram. The left solenoid (E8AE-9H465-BA) controls the vacuum to the activation side of the axle engagement diaphram. Ford has been having chronic problems with water entry into these solenoids, corroding them from the inside and seizing them,as you've seen!<O></O>
They've been redesigned and those old part numbers (E8AE-9H465-AA/BA) have been superseded.

The latest designs are listed as:
Disengage solenoid 6L3Z-9H465-A (identified by electrical connector rib at 9:00 position)
Engage solenoid 6L3Z-9H465-B (connector rib at 6:00 position).

3. Check your vacuum lines: This is a little tricky to do becuase they wind their way from the solenoids all the way to the 4WD actuator on the front axle. One hose leaves from each solenoid at the front (close side to the battery) and one is pink and the other is blue(greenish if older). Follow the lines down as best as you can, checking for spots with wear or rubbing. Also make note if they seem old and brittle as there could be a crack you don't see. Mine were rubbing a bit on the passengers side wheel well so check there. Now crawl under the truck and in the centre on the axle is the actuator diaphragm. It is under a cover that is easily removed with a socket and the two hoses are attached to it. Pull the hoses off and while the truck is on, and someone shifts it in and out, put a finger over the end of each hose. The vacuum should alternate hoses when shifted and the pressure should be equal although it is surprisingly not a strong pull. If your hoses look good and suck like I said, they should be all good (this also confirms that your solenoids, and vacuum reservoir are working as well.)

4. Vacuum actuator function: This is easy to check. Crawl under your truck, take off the cover for the actuator and watch as your friend shifts from 4X4 and back. When the truck is shifted to 4X4, the shaft should slide into the diaphragm, moving the lever it is connected to to the passenger side direction. When shifted back to 2 wheel, the shaft should slide out of the diaphragm towards the drivers side. The movement is about 2 inches total and happens smoothly.
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If this works, then you may want to check to see if the shift fork (the lever that the actuator moves) is not bent or broken, or the pin that holds it in place is not sheared. It this all good, then maybe your front differential needs help?

If the diaphragm moves stiff and short, it is one of two problems: there is a tear in the diaphragm or the shaft has corroded and is stiff and needs lube. To check if the diaphragm is just stiff, assist the truck by pushing the shaft in an out by hand. This should engage and disengage the 4X4. When I did this, I engaged the 4X by pushing the shaft in but it was very stiff and hand to pull it out again with leverage from a screwdriver. Mine was just stiff and needed lubrication - which worked! If you can move it freely by hand, I would say there is a tear in the diaphragm and you probably need a new one. Try ebay -- they are $100 where at Ford they are $460!! Part number is F65Z-3G360-BA

Hopefully this helps and will guide some other less than mechanical people towards fixing a problem for cheap or free!
When turning ESOF to 4L vehicle engages 4L Operation. Turn ESOF to 4H, vehicle disengages to 2H operation.
Turn ESOF to 2H, vehicle engages in 4H operation.
Anyone have any suggestions for a fix?
Old 05-21-2018, 10:08 PM
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Others know much more than I but I would check under the hood and see if somebody accidentally got the electrical connectors switched on the solenoids or maybe the vacuum lines. However, I think that would just affect the 4WD actuator at the front axle. I would also check the dash switch resistance at each position 4low 2hi 4 hi. 2hi 4100-3700 Ohms 4 hi 1050-1150 Ohms 4low 380-340 Ohms
Old 12-11-2018, 03:20 PM
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Originally Posted by slowstang View Post
Since I have to wait for moderator to approve a new thread... trying to copy and paste here.

Yes, I know there is a sticky on troubleshooting. I've read it along with dozens of other posts probably at least 10 times now. I'm pretty confident that I have seen every single thread/post out there on troubleshooting ESOF 4X4 issues. So with that said, I'm STILL looking for help before I have to swallow my pride and take it to a dealer that has the cool kid scan tool that will see and manipulate the GEM...

Issue started with 4X4 NOT working (worked fine last winter). Turn **** to 4Hi, nothing...no relay click, no dash light, like the switch wasn't even working... Checked fuses inside and underhood and those were still good.

Then, since it was quick and easy, I tested with another selector switch and still nothing.

Then, went ahead and swapped BOTH solenoids, as both had good vacuum coming in, disconnected battery just to "reset" everything and then turned key on, turned selector switch to 4Hi, got a SINGLE "relay click", but no light, no engaging anywhere...still nothing

Then, grabbed another transfer case shift motor, disconnected battery again while swapping out, hooked everything back up and started the truck. Turn the selector switch to 4Hi and then "click click", "clunk" and 4X4 Light comes on. Drop it in drive, could tell front was definitely engaged and I'm thinking "Cool, it was just the shift motor"

Then I move selector switch back to 2Hi....NOTHING. No click, no clunk, light still showing 4X4 on dash and NOW the truck is stuck in 4Hi and will not come out... So I went from not being able to get 4X4 to not being able to get rid of it. I took the shift motor back off the transfer case and manually moved the shaft back to 2Hi and then manually moved the actuator to disengage the front axles to be able to at least drive it.

Started pulling dash apart today, hoping to find good old fashioned relays, and ended up seeing another stupid module. So the transfer case relay module seems to be getting power, but still nothing.

I haven't had the windshield leak issues, so there is no issue where water would've made it to the GEM. And if the GEM was actually bad, I'd expect I'd probably be having some of the other issues like wipers, power window, dome lights etc. that come with bad GEM...

So if anyone has any suggestions, I'd welcome it! I ran across a post saying they replaced a "Transmission Range Sensor Switch" because the ball was sticking a little and that fixed their issue, but I'm not seeing that part anywhere like it said on the transfer case, so maybe it was a floor shift optioned truck instead of the dash switch....

Really, I don't want to hear a dealer say "That'll be $1000". I don't claim to be a mechanic, but I'm not completely ignorant either. I just feel like there is something small I'm missing somewhere.
this is the same problem I have. turn truck off it will go back in 4x2 cant switch on the fly trans start sqealing til I slow down then it goes into 4x4 and 4x4 lo does nothing.
Old 12-12-2018, 12:41 PM
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could there be a leak in the vacuum line that disengages the 4wd?
Old 12-14-2018, 02:05 PM
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I got a uses dash switch off ebay and put it in and now it works fine.reinstalled old switch and it still work fine so I dont know whats going on with it.
Old 12-14-2018, 06:00 PM
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Christmas miracle
Old 05-18-2019, 04:35 PM
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I will post this and hope an answer comes back before Noon on Sunday. (I need help as this vehicle is going to turn me psycho.)

I go to check a new alternator (The third one I replaced in a full month) to see if a pin was left in the device. When I saw no pin was available, I reinstalled the Alternator.

I get soldering wire and a soldering iron to fix a problem with the speedometer being out. Also the battery light was on after replacing the second alternator with the third one.

After soldering the electronic component, I replace the dashboard to have the following issues:
  • Dashboard works EXCEPT for the speedometer
  • Battery light is still on
  • When I turn the key, The startup process takes place, but no ignition.
I am supposed to have this vehicle pass emissions by the end of the week, and I am totally broke because of the FDBS I experience with the upkeep of this vehicle. I will humbly ask someone for answers and a plan I can work with. I have to have this vehicle running by Sunday night. I have no means of transportation into work without it.

Email me with any ideas at [email protected]. I live in Milwaukee, WI - a place that is a blessing AND a curse.


Earl D. Lewis
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