2002 Explorer 4x4 Doesn't Work: Solution

[ttiwkram]

I was recently able to fix my “4 wheel drive doesn’t work” problem thanks to contributors to this site. (Thank you all!) But I found there was no single thread that had all the information I needed, so I decided to add this post to summarize the problem and solution in one place.

Symptoms:

- 2002 Explorer, no 4WD function (electrical or mechanical) whatsoever.

- Vehicle reverted to 2-wheel rear drive and fishtailed on slippery roads.

- “4x4 Low” light (left side of instrument cluster) would illuminate during lamp test at engine start, but “4x4 High” light would not.

- No 4x4-related buttons (4x4 Auto, 4x4 High, 4x4 Low) or associated indicator lights worked.

- All 4x4-related fuses good.

- No trouble codes set in OBD II system.

Diagnosis:

Dead 4x4 Control Module.

Repair:

Replace the 4x4 Control Module as follows:

- Disconnect the vehicle battery.

- Open the glove box. Squeeze its sides toward the center and pull the glove box all the way open so that it flops down and you can see/reach behind it. The 4x4 Control Module will be visible slightly to the left of center.

- Remove the one screw holding the module’s bracket in place. Pull out the module along with the bracket. (You now have access to both screws that hold the module to the bracket.)

- Remove the two remaining screws and unplug the two wiring connectors from the module.

- Installation is the reverse of removal. When you reconnect the battery, don’t be surprised if you hear some clicking and buzzing from the general area of the module for 45 seconds or so. I think this is just the module introducing itself to the other computers and/or actuators.

Parts Source:

Original part numbers vary (as do the replacement parts), so when you go looking for a new part be sure to have your original part number and vehicle identification number so your supplier can translate them and find the correct new part.

I got my new 4x4 Control Module for $173.15, shipping included, from my new best friend: Ed Olson at Millennium Ford in Seattle, Washington, 1-800-562-5250. Ed’s email address is parts@millenniumford.com.

Possible pitfalls:

1 - The 4x4 Control Module is not to be confused with the “Powertrain Control Module” (formerly and more accurately known as the “Engine Control Module”).

2 - Some dealers will be glad to charge you $400 for so for the module, and an extra $225 for the ten-minute installation. The common claim is that the module has to be programmed, and that justifies $1,350 per hour. Hogwash! The module screws and plugs right in, and automatically does its own handshaking at power-up.

3 - Don’t use the Haynes manual (#36025) for 2002 - 2003 Ford Explorers. The folks at Haynes are clueless with respect to 4WD -- They don’t even know the 4x4 Control Module exists!

Possible Long-Term Solutions:

1 - Hopefully, the replacement parts will prove better than the originals. There have been many reports of modules failing after a vehicle’s battery was replaced. In my case, we didn’t replace a battery, but we did jump-start the Explorer once. In either case, it’s evident that power surges fried the modules because Ford provided frail and feeble electronics for service in an electrically hostile environment.

2 - In order to absorb future power spikes, I added a 2,200 uF capacitor in parallel with my vehicle’s battery. I don’t know if it will do enough good, but so far it hasn’t done any harm.

3 - No more post-1975 Fords for me. ;-)

 

[originaljrock]

do you happen to know if there is a way to test the switch before assuming the module is bad. I am having that same problem. A buddy of mine told me he has seen two in the past couple months with the same problem. One was a bad switch and one was the module. The repair manual I bought says nothing about the 4wd system. I can't even get a wiring diagram.

 

[rrgone]

Very nice writeup ttiwkram. Thanks for pointing out that the bracket holding the module comes out with just one screw. I removed the module from the bracket while it was in-place and that rear screw is a bugger.

Note to mods: This should definately be a sticky here!

 

[hamptonbigdog]

nice write up! I took my 02 explorer to the shop and it pulled code b1342 electronic module failure. My friend works at the parts for ford and he said the part is 380.00 but he is going to let me have it at cost 191.00 dollars. I gave him my vin # but he stills wants the part # off of the old module because he said there is three different modules. So for anyone that goes and buys one of these take your old part # and have vin#. Also I checked the price of the 4x4 shift motor cost 212.00 and the price of trans filter and gasket 30.00 cost and checked price of rear wheel bearings and clip ring 79.00 and also the price of ford belt 29.00 and pulleys 13.00 and tenisoner pulley 30 cost.

 

[hamptonbigdog]

also you can get the shift motor at napa for 178.00

 

[ttiwkram]

4WD Switches

do you happen to know if there is a way to test the switch before assuming the module is bad. I am having that same problem. A buddy of mine told me he has seen two in the past couple months with the same problem. One was a bad switch and one was the module. The repair manual I bought says nothing about the 4wd system. I can't even get a wiring diagram.

Hi -- It sounds like you may also have a Haynes manual (yechhh...)

I know what you mean about the switches. That was my first suspicion, because I had recently installed a trailer brake controller. I thought maybe I had knocked a wire off the back of one of the switches, but it occurred to me that I had successfully used 4WD after installing the controller.

Checking the switches should be straightforward. You'll have to remove the center dash panel bezel. I haven't done it, but the writeup implies that the switches are attached to the bezel itself and you just unplug the wires from the assembly as you remove it. Then you should be able to use an ohmmeter on each switch's terminals to see if the resistance changes as you actuate the switch. (A dead switch would give you no function -- i.e., no change in resistance.)

I would guess that the chance of all three switches (Auto, Low, and High) failing simultaneously would be almost zero unless a common feed pooped out. If only one switch failed, the other two modes should still be available. But since checking them is essentially free, it sounds like a good approach. Remember to also check the small handful of fuses associated with the 4WD system.