1996 4.0 V6 4x4 w BW 4405 t-case. No 4wd. | Ford Explorer Forums - Serious Explorations

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1996 4.0 V6 4x4 w BW 4405 t-case. No 4wd.


December 21, 2017
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Year, Model & Trim Level
Ford Explorer 1996 4.0 V6
Hi folks,

The guy that sold the car said everything working and during the short test drive last summer, yes, and apparently not...

Well, been fixing this and that. Brakes, brake lines, driver door harness wirings (mirrors, door locks, power windows)

But I still have no 4wd. Pretty annoying with 4x4.

Started with blinking 4wd lights with 4wd Auto when I thought I really could use 4wd. With 4wd Low I could hear the clunk from t-case. The tf-case shift motor working obvioysly.

Bought an OBD interface. Scanned with FORScan. Got code for tf-case rear shaft sensor. Replaced that. Blinking dash lights went away but then code for front shaft sensor. Replaced that.

Now dash lights not blinking, 4wd Auto light and 4wd Low light come up accordingly and t-case gives the 'clunk' when swithing to 4wd Low.

New codes from scan:

P1804 - Four wheel drive high indicator circuit failure
B1302 - Accessory delay relay circuit failure
P1820 - Transmission transfer case low to high shift relay coil circuit failure
P1828 - Transmission transfer case high to low shift relay coil circuit failure

Any advice would be appreciated.

Cheers and Merry Christmas,


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Would the 'brown wire mod' bypass all this and force the system into 4wd? Assuming the t-case is ok. All I really want is the 4wd low to work _when_ I want it.

Hi all,

I am trying to understand this brown wire mod for 1996 Explorer from here:

How to: - The Comprehensive Brown Wire Mod Thread

Would the wiring for 4high go like this? (as in the uploaded / attached file)

Please, anyone?


Or rather like this?

Position 1&2: normal, same as uncut and GEM connected.

Position 2&3: cut, GEM disconnected, aux power to TCCC.
2wd = 100%4wd, 4wdAuto = 100%4wd, 4wdLow = 100%4wdLow.
HAL-sensors, TOD-relay and GEM bypassed.


After some reading, I got GEM and TCCC wrong in the previous image, they are apparently viceversa. And that's why I couldn't quite understand it. This should be it? With the extra switch off (position 1&2 connected) it's normal and same as not cut. Switch it on (position 2&3 connected and GEM + TOD disconnected) and you have full 4wd all time, high and low. Or could someone please correct me if I'm wrong?


The 96 has the controltrac system, meaning in 4x4 auto the tcase will only engage the front if it detects a difference in wheel speed between the front and rear wheels, then will disengage it when wheel speed equality is restored. If you need 4x4 that wont decided to engage and disengage on its own you'll have to use 4low. This never bothered me because if there was a reason I needed 4 wheel drive, then there was reason I dont need to be going highway speeds either, so 4 low was fine for me.

This brown wire mod will engage the tcase in 4high and give you full time 4high. I can't however answer any questions as to how to wire it. I do know you will be wanting to wire so that the tcase stays engaged in 4high as opposed to giving you true 2wd in later years with a different system.

Only other advice I can offer is to ditch the 4405 tcase you have now and swap in a manual shift BW1354. You will have to wire up a switch to engage and disengage your front center axle disconnect, but the 1354 is a much stronger tcase. I use my truck mostly for wheeling and the 4405 only lasted a couple years for me.

Thanks for your advice. I was thinking about a reman t-case but I thought I'd first give a try to fix this one.

So, after being away some time I did the wiring. Should I hear a clunk or some engaging sound from the t-case (clutch) when the extra switch is switched on? I get nothing. So it could be that the t-case clutch coil is busted or it does not get power?

So next thing is to check if it gets power. Is there a relay for the t-case clutch coil too?


After a while, at this again. Replaced the transfer case switch relay (under GEM behind radio) with a new one and I am now down to one single DTC: P1812.

===GEM DTC P1812===
Code: P1812 - Four wheel drive mode select circuit failure
Module: Generic Electronic Module
Diagnostic Trouble Code details
Four wheel drive mode select circuit failure
--- Possible Causes --------
P1812 can be generated by:
-Open 4-Wheel Drive Mode Switch
-Suspect 4-Wheel Drive Mode Switch
-Suspect Generic Electronic Module
NOTE: For Vehicles with 4x4 Option
If you encounter this code when you are in 4x4 Low mode, rerun the Self-Test in the 4x2 High mode. If you still generate code P1812, there is a 4-Wheel Drive Switch/Circuit problem.
===END GEM DTC P1812===

Checked and measured, with known good ground and ground from t-case bolt/t-case itself, the brown wire going into t-case (from the connector pin under the car) and sure enough, power is there when the extra switch is on. Still nothing. Something busted inside the t-case? T-case clutch coil? Some solenoid? Another relay somewhere?

I'm lost...