4x4 problem (wont engage)
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4x4 problem (wont engage)
i have a 99 f150, 4.6L, 4x4 w/136,000 mi. i tried to shift into 4x4 the other day and nothing happened. i went to 4lo and it remained in 2hi. when i shift it, i can hear it clicking like it is engaging and the 4x4 lights will come on. a day or two later i tried it again and it would not go into 4hi but when i put it in 4lo it went to 2lo. which was different than before. any ideas of what i am dealing with??
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From: E.Lincoln County, NC
To check the disconnect motor:
Do the easy part first. Check the vacuum solenoids on the cowl to see if they're sending vacuum to the vacuum motor on the axle. The right solenoid (2WD/disengage) should have have vacuum on the pink line when in 2WD. The left solenoid (4WD/engage) should have vacuum on the blue line when shifted into 4WD. Just pull the relative colored line for the shift position and leave the supply lines connected (black/white).***Note: My lines are all faded out***
If they're in operation you'll have to crawl under the truck, remove the vacuum motor cover and disconnect/check for vacuum there. When you put the lines back on be sure you connect the blue to the side with the plunger.
SEE ALSO: https://www.ford-trucks.com/forums/6...low-range.html
Do the easy part first. Check the vacuum solenoids on the cowl to see if they're sending vacuum to the vacuum motor on the axle. The right solenoid (2WD/disengage) should have have vacuum on the pink line when in 2WD. The left solenoid (4WD/engage) should have vacuum on the blue line when shifted into 4WD. Just pull the relative colored line for the shift position and leave the supply lines connected (black/white).***Note: My lines are all faded out***
If they're in operation you'll have to crawl under the truck, remove the vacuum motor cover and disconnect/check for vacuum there. When you put the lines back on be sure you connect the blue to the side with the plunger.
SEE ALSO: https://www.ford-trucks.com/forums/6...low-range.html
Last edited by ncranchero; Jul 5, 2007 at 05:57 PM.
Postmaster
Joined: May 2003
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From: E.Lincoln County, NC
I put my vacuum motor back on yesterday and it wouldn't engage the front axle. 
Fords wiring/vacuum diagram I posted is wrong!! 
The blue line goes to the back of the actuator/motor and the pink line goes to the side with the plunger! Works great like that! Sorry for the wrong info but it was from FORD not me. 
Fords wiring/vacuum diagram I posted is wrong!! The blue line goes to the back of the actuator/motor and the pink line goes to the side with the plunger! Works great like that! Sorry for the wrong info but it was from FORD not me.
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i got under the hood today and believe that i have found the problem. i had my battery post cleaned off a while back and some of the acid had made it was down to the vacuum lines and melted two of the lines. thanks for your help. it shouldnt be a hard fix at all...any idea how much the vacuum lines would run? it is just from the firewall to the fender well....the rest are in good shape..
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From: E.Lincoln County, NC
Someone posted that they had bought a new set but I don't remember who or how much. Maybe they'll read this and post the $$$.
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$154 for the upper & $154 for the lower!! - any cheaper???
I priced out the lines at Ford and they were $154 for the upper and $154 for the lower. THere has to be a cheaper fix. Any ideas???
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From: Near the racetrack, WA
Originally Posted by ncranchero
If they're in operation you'll have to crawl under the truck, remove the vacuum motor cover and disconnect/check for vacuum there. When you put the lines back on be sure you connect the blue to the side with the plunger.
Postmaster
Joined: May 2003
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From: E.Lincoln County, NC
Originally Posted by shoeman502
I priced out the lines at Ford and they were $154 for the upper and $154 for the lower. There has to be a cheaper fix. Any ideas???
Postmaster
Joined: May 2003
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From: E.Lincoln County, NC
Originally Posted by gustav129
Where exactly is this located at underneath? I don't have this truck, but a co-worker has the same problem, and I want to point them out to him to test them.
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Hey all.
I am having issues with 4H and 4L engaging on my 98 F150 and I found this thread to be very helpful, thanks!
Unfortunatly I have not figured out my problem. Here is what I have done.
1. I made sure both solenoids had a good supply of vacuum.
2. I did the vacuum test on the vacuum motor from up top and it held fine on both lines.
3. Checked the fuse for the solenoids.
When in 2H the correct solenoid passes vacuum to the output. However when I shift into 4H or 4L I get nothing from the 4wd solenoid and the 2wd continues to pass vacuum. I can feel the transfer case engaging.
I also am not getting a 4x4 lite on the dash. It was working last winter when I started having problems with the 4wd engaging but now it wont light up at all. It lights up during startup so I know the bulb in the dash is good.
I tried removing and re-seating the indicator switch hoping it was just a bad connection but no go.
Any ideas?
I am having issues with 4H and 4L engaging on my 98 F150 and I found this thread to be very helpful, thanks!
Unfortunatly I have not figured out my problem. Here is what I have done.
1. I made sure both solenoids had a good supply of vacuum.
2. I did the vacuum test on the vacuum motor from up top and it held fine on both lines.
3. Checked the fuse for the solenoids.
When in 2H the correct solenoid passes vacuum to the output. However when I shift into 4H or 4L I get nothing from the 4wd solenoid and the 2wd continues to pass vacuum. I can feel the transfer case engaging.
I also am not getting a 4x4 lite on the dash. It was working last winter when I started having problems with the 4wd engaging but now it wont light up at all. It lights up during startup so I know the bulb in the dash is good.
I tried removing and re-seating the indicator switch hoping it was just a bad connection but no go.
Any ideas?
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Joined: Dec 2008
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My 4wd light worked and I could hear relays click inside the dash, but no 4wd. Thanks to the info here I was able to find the problem. I was following the vac lines from the fire wall when I noticed some black goop that appeared to ooze out of the black plastic conduit that housed both pink and blue lines right next to the battery tray. As I peeled open the conduit and tugged on the lines I found the blue one was melted in two. I trimmed the ends up and spliced in a short piece of brass tubing using silicone fuel proof tubing (like used in R/C models). Now it's working like it should....YES! Thanks for all the good info - let me fix it on the cheap.
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Joined: Sep 2008
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From: Cape Cod Ma.
4WD won' engage?
Wow great info here.
I am having the same issue. My 97 F250, 3 days ago when getting ready to set up for plowing. I tested the 4wd & it went in & worked fine.
Then the next day we get 14" of snow.I go out to make some $ & I put it in 4W Lo. Lights on the dash are lit. But it will not enage? I got under the truck & tried to hit the acuator motor with no luck.
Next day I bring it to my local garage & they put it on the lift, verified I had good vacuum at the acuator motor & when the put the vacuum lines back on it went right into 4WD. But from in the cab once you shift the shifter lever from 2WD to 4WD it will not engage.
The garage was able to use some cable ties to engage the acuator motor full time 4WD (just so I could plow my customers).
They tell me it has a "sticky diafram". They want $200.00 for the part (Dealer part only) & 1 hour labor to install.
Does this sound right & fair? Or can I buy the part cheaper on my own? And can I put it in myself. I'm a fair wrench, just never did any 4WD work.
Thanks
Bob
I am having the same issue. My 97 F250, 3 days ago when getting ready to set up for plowing. I tested the 4wd & it went in & worked fine.
Then the next day we get 14" of snow.I go out to make some $ & I put it in 4W Lo. Lights on the dash are lit. But it will not enage? I got under the truck & tried to hit the acuator motor with no luck.
Next day I bring it to my local garage & they put it on the lift, verified I had good vacuum at the acuator motor & when the put the vacuum lines back on it went right into 4WD. But from in the cab once you shift the shifter lever from 2WD to 4WD it will not engage.
The garage was able to use some cable ties to engage the acuator motor full time 4WD (just so I could plow my customers).
They tell me it has a "sticky diafram". They want $200.00 for the part (Dealer part only) & 1 hour labor to install.
Does this sound right & fair? Or can I buy the part cheaper on my own? And can I put it in myself. I'm a fair wrench, just never did any 4WD work.
Thanks
Bob
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Joined: Dec 2003
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Is there a way to test the 4X4 switch on the dash? I don't hear any clicking or anything whatsoever when I turn the switch. I checked the fuses. (There are only two, yes? One small one in under dash fuse box and a second big one under the hood.)
I pulled the switch off and put a multi-meter on it. I get continuity between the outermost terminals regardless of what position the switch is in. I get zero continuity between any other combinations of terminals, regardless of what position the switch is in. This doesn't sound right, but I really don't know if there is more to testing this switch than a simple continuity test.
I didn't even remember clicking and such under the dash when I engage 4X4; I use it so seldom. I get no sound whatsoever now.
Of course, the only time I realize my 4X4 don't work is when it's frigging 20 degrees out.
I pulled the switch off and put a multi-meter on it. I get continuity between the outermost terminals regardless of what position the switch is in. I get zero continuity between any other combinations of terminals, regardless of what position the switch is in. This doesn't sound right, but I really don't know if there is more to testing this switch than a simple continuity test.
I didn't even remember clicking and such under the dash when I engage 4X4; I use it so seldom. I get no sound whatsoever now.
Of course, the only time I realize my 4X4 don't work is when it's frigging 20 degrees out.