I have a 1998 f150 4.6L and I've replaced the selanoid and the motor for the 4x4, and yet i still can't get it to work. Anyone I've asked can't find the problem. The 4H light will come on but it won't engage and the 4L light won't even come on. Any suggestions?
Check BJB ( aka Battery Junction Box, Engine Compartment fuse panel ) Fuse #17. This is the power to the Transfer
Case shift relay, which powers the Shift motor in the Transfer case and power to the magnetic clutch coil ( via the transfer case relay ).
The other fuse to check is the CJB ( aka Central Junction Box, cab fuse panel ) Fuse #23.
If both fuses check good, time to check for power on the connector for the shift relay and the shift motor. The power from BJB Fuse # 17 is the Dark Green w/ Light Green stripe ( this is hot at all times ).
The old school test is to lightly hit the back of the transfer case, to see if the shift motor is hung up.
Here are the diagrams, so you can see what I am talking about.
With the transfer case not shifting into 4WD, it is either power to the shift motor, or the shift motor itself that is the issue.
I have not seen that many bad shift motors myself, usually it is the electrical connector to the transfer case that is corroded, or in 1 case, the owner accidentally cut the shift motor wire in the truck ( didn't realize it until he found the dead wire at the connector ).
The power to the switch runs through the resistors in the ESOF switch, to let the GEM ( Generic Electronics Module ) know what it should do with the shift motor ( 2WD, 4H or 4L, and for 4WD, if the truck is moving too fast to let it shift, or in the case of 4L, if it is not in park or neutral ).
Take a look for the electrical connector on the side of the transfer case ( forget which side it comes in at the moment, and look for the color wires noted in the last post, and check for power ( polarity is one direction for L2H and the other for H2L )
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It took me three day testing relays fuses Every one talks about the four wheel drive selcter switch the vacuum relays and the shift motor when it ended up being the transfer case shift control relay it is mounted under the dash on top of the
Stereo if you have a clicking nose coming from your dash that is the first place to start looking if you four wheel drive won't engage.
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It is an ESOF, I just lifted the truck with the key to on and switch to 4H, the light came on, but no noise as if it wasn't even trying to engage. The only noise was the light itself flashing in the dash about 3 or 4 times then it stayed lit, but no mechanicle noises what so ever. The front drive shaft spun. Not sure what this means.
So ive checked the fuses and they are both good. unfortunately I do not understand these diagrams, never been good with the electrical side of things. But I hit the back of the transfer case and nothing happend. The switch has power but the power doesnt seem to be getting anywhere. I've checked the vacuum lines and they all seem ok. Not sure where to go from here.
Is it an ESOF ( Electronic Shift On the Fly ) or MSOF ( Mechanical Shift on the Fly ) ? Sounds like an ESOF ( with the motor replacement being the shift motor ). Lift and support the front of the truck so the front wheels are off the ground. Key to run position ( do not start ) , engage 4x4 and try to turn the front drive shaft. If it turns it is a problem with the transfer case. If it doesn't it is a front axle engagement problem. If you replaced both of the vacuum solenoids, it could be a transfer case issue ( confirmed with the test above ) or the vacuum lines to the vacuum disconnect motor, or the shift forks in the axle. With the new shift motor installed, could be power to the shift motor ( connector ) also, but rather than guess at what it is, after the front drive shaft test, we can get a direction to go with your issue.
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