4x4 doesn`t conect
- Thread starter PEDROFMX
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loulblades
Full Access Member
Not sure what you mean that it doesn't connect.
If the relay sound you are hearing is inside the cab, that would be the TCCM trying to activate the 4WD.
When you select 4HI, does the light come on (flash) and go off again or does it stay flashing?
There are basically 5 parts involved in the 4WD train (not including the fuses of which there are 2, both in the fuse center on the driver's side of the IP):
1. the switches (I replaced within last 2 years)
2. the TCCM (transfer case control module) (replaced within last 2 years)
3. transfer case encoder motor
4. transfer case switch
5. front diff actuator (replaced recently)
Of course I have made the assumption that this is an all electric/electronic setup.
From what I have seen it appears the actuator would be the #1 culprit then the transfer case switch.
Early build '96s had a thermal actuator which takes longer to operate when the weather gets cold. There is a TSB (I don't have the number but have posted it before) to change to a motor driven actuator and, IMHO, is well worth it.
I am currently chasing down a problem with my 4WD and it appears to be the encoder motor (one thing I have not replaced). At least that is what the fault code says (#2).
If the relay sound you are hearing is inside the cab, that would be the TCCM trying to activate the 4WD.
When you select 4HI, does the light come on (flash) and go off again or does it stay flashing?
There are basically 5 parts involved in the 4WD train (not including the fuses of which there are 2, both in the fuse center on the driver's side of the IP):
1. the switches (I replaced within last 2 years)
2. the TCCM (transfer case control module) (replaced within last 2 years)
3. transfer case encoder motor
4. transfer case switch
5. front diff actuator (replaced recently)
Of course I have made the assumption that this is an all electric/electronic setup.
From what I have seen it appears the actuator would be the #1 culprit then the transfer case switch.
Early build '96s had a thermal actuator which takes longer to operate when the weather gets cold. There is a TSB (I don't have the number but have posted it before) to change to a motor driven actuator and, IMHO, is well worth it.
I am currently chasing down a problem with my 4WD and it appears to be the encoder motor (one thing I have not replaced). At least that is what the fault code says (#2).
Obliterous
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Where is the tccm?
I'm having a similar problem, and was informed by a service center that the TCCM may be bad. the problem is, that the darned thing is NOT where they tell Me it is.
I was TOLD that the tccm is located behind the passenger side kick panel, and the only thing behind the panel is the wiring harness that leads to the passenger door. help?
I'm having a similar problem, and was informed by a service center that the TCCM may be bad. the problem is, that the darned thing is NOT where they tell Me it is.
I was TOLD that the tccm is located behind the passenger side kick panel, and the only thing behind the panel is the wiring harness that leads to the passenger door. help?
loulblades
Full Access Member
Didn't see what year you have but on my '96 the TCCM is located on the driver's side of the steering column near the firewall. It is a metal box about 5" x 4" x 1". If you hear clicking under the dash when you press the 4WD button then follow that sound.
Mechanics I have talked to have said they don't see bad TCCMs often. But if there is a one in a million chance and you are the one...
Mechanics I have talked to have said they don't see bad TCCMs often. But if there is a one in a million chance and you are the one...
Obliterous
New Member
- Joined
- Jan 24, 2009
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Sorry, I have a 99 hoe, I'll have to add a sig. 
Thanks for the info on locating the tccm, was right where you said it was.
Turns out that there was a bit of internal shop drama where I took My hoe for the check, and now they cant even tell Me what tests were run. The Mechanic that did the tests was fired the same day...
So, As I understand it, there's a few possible points of failure on this system. TCCM, switch module, encoder assembly, and front axle actuator.
Can you describe basic methods for testing each component?
As it sits now, I no longer have a service 4wd light on the cluster, but all five indicator lights on the switch assembly are dimly illuminated. (neutral, 2wd, 4wd auto, 4-hi, 4-lo) I have no 4wd functionality.
it appears that the pcm trouble codes were cleared at the shop, and due to their drama, they cant tell Me if any codes were present.
I'm concerned about the stability and reliability of the power train, as this is My wife's primary driver.
Also, are the encoder assemblies sealed units? I'm concerned that it may have internal water damage, as it was underwater during a flood that invaded the interior of the hoe (but didn't get the TCCM wet)
I plan on pulling the encoder assembly to inspect and clean it, and have been told that there is a procedure for `clocking' it to the tccm. Can anyone enlighten Me on that procedure? (a search didn't turn up any relevant hits, but I may not be using the right search terms)
(I miss the days when six wires going to the engine was enough)
Thanks for the info on locating the tccm, was right where you said it was.
Turns out that there was a bit of internal shop drama where I took My hoe for the check, and now they cant even tell Me what tests were run. The Mechanic that did the tests was fired the same day...
So, As I understand it, there's a few possible points of failure on this system. TCCM, switch module, encoder assembly, and front axle actuator.
Can you describe basic methods for testing each component?
As it sits now, I no longer have a service 4wd light on the cluster, but all five indicator lights on the switch assembly are dimly illuminated. (neutral, 2wd, 4wd auto, 4-hi, 4-lo) I have no 4wd functionality.
it appears that the pcm trouble codes were cleared at the shop, and due to their drama, they cant tell Me if any codes were present.
I'm concerned about the stability and reliability of the power train, as this is My wife's primary driver.
Also, are the encoder assemblies sealed units? I'm concerned that it may have internal water damage, as it was underwater during a flood that invaded the interior of the hoe (but didn't get the TCCM wet)
I plan on pulling the encoder assembly to inspect and clean it, and have been told that there is a procedure for `clocking' it to the tccm. Can anyone enlighten Me on that procedure? (a search didn't turn up any relevant hits, but I may not be using the right search terms)
(I miss the days when six wires going to the engine was enough)
loulblades
Full Access Member
I did post some diagnostic procedures in the troubleshooting section. Unfortunately for you the procedures apply to non-auto systems. I am sure that some parts of it would apply though.
Sealed or not, water has a way of finding it's way in when a vehicle has been setting in it for awhile.
Sealed or not, water has a way of finding it's way in when a vehicle has been setting in it for awhile.
