Good morning folks,
My 4WD isn't working. Its an 88 Bronco II automatic with the electronic 4WD switch on the overheqad console. Nothing at all happens when you hit the button (no relays clicking). I've been doing some reading on this board and I'm seeing stuff saying its a fuse or the 4WD module (I forget the acronym, its early). I looked in the haynes manual and the owners manual and they mention a fusible link attached to the starter relay but not a fuse. Is this what folks were talking about when they say fuse? If so, how do I identify what it is at the starter relay. Also is this something I'm going to have to buy from Ford, or will my friendly neighborhood parts guy carry it?
Thanks, looks like its gonna snow tomorrow...

Brian

 

Hi, I can't help with your problem since I have the same one. The electronic four wheel drive worked fine last year but not now. Did you find an answer, if so could you let me know what it is?
Thanks,
George

 

OK folks, 53 views and no one knows what the fusible link at the solenoid looks like? Surely someone has changed this out.
I'll be checking the control module this weekend, but would like to check this fusible link if the module checks out OK.

I've read every thread I can find on this subject but haven't found one that answers my question yet.

Thanks everybody,
Brian

 

Brian,
The fusible link looks like any other wire, the difference is that it's a smaller gauge than the wire it's connected to so that it will burn out if the circuit is overloaded. They usually have a fat rubber end on them. They come in different colors and thicknesses. Without a wiring diagram I can't tell you which one it is. If it's burned out you should be able to tell by feeling it. I had one burn out but the insulation still looked okay but by touching it I could tell there was nothing inside it. These fusible links can be gotten at any auto store.
George

 

the fusible link at the starter relay is only for the charging system. it wouldnt have any effect on the 4wd. you need to find the fuse box or boxes and just check to see if any fuses are burned.

 

Norcalcapri,
My owner's manual, on the chart listing fuses and fusible links calls for a 20 gauge fusible link protecting the "4X4 Electric shift" circuit located at the starter motor relay. It calls out for a 16 gauge fusible link protecting the alternator, also at the starter relay. Am I missing something???

George,
I'll look around in there this weekend (its dark by the time I get off work) and see if I can find something that seems fried. Thanks for the info.
Brian

 

I hope this helps.

This reply to a previous post is the best description of the elec. shift 4x4 I've seen.
It was posted by Hooked on 4WD.
As for the fusible link problem I would take a test light and probe the wires on each side of all of them that are hooked to the starter relay. If you find one that is bad replace it.


Written by Hooked on 4WD

It sounds like you have a reference manual of some kind, so I don't know whether it's necessary to explain how to run the Self-test on the Transfer-case Electronic Control Module. The light should blink about once per second for a "Pass" condition. Anything else indicates a failure.

The '88 Bronco-II I got for use as a parts doner to fix the major problems on my '84, had a lot of irreparable weather related damage. It electronic transfer case was working in fits, and I guess that's why I kept the 5-speed and manual case originally built into the '84.

One peculiar thing I discovered during the time I had the '88 was the inner plastic fender "splash" shield on it had somehow gotten pushed up to where its lower-back edge was caught and pressing down on the flex-conduit-wrapped wiring harness against the hole in the frame through where it is routed.

I don't know how it got in that position, maybe a build-up of snow inside the fender which was pressed up on by the front wheel being turned left while moving forward. Nor can I say exactly how long it had been that way, but it was apparent it had been in that position for quite a while, as the flex-conduit was completely cut through and the insulation on a few wires was perforated and making contact with the edge of the hole. There was ONE wire, who's conductor strands were completely severed. After checking, it turns out the cut wire, wasn't for anything critical; one of the dash "4x4" indicators.

The wiring for controlling the electric shift-motors runs under the carpet along side the center bulge in the floor, next to the driver's seat, then goes through a grommet in the floor. There are multi-pin connectors directly on top of that tunnel just under the dash, for that harness. The rest of the wiring goes behind the dash panel over to the electronic control module, as well as behind the instrument cluster and through the left windshield pillar on its way to the Overhead Console. On the '88, all of that wiring was in great shape.

I don't know what, if any of the wiring going down the left frame rail is pertinent to the "4x4" control electronics, so looking in that direction may not help your situation. However, there are "P"ark and "N"eutral sensors which are checked for a "True" status condition prior to activating the shift motors. Wiring to/from those switches on an automatic transmission usually runs down along the top of the transmission. That wiring and.or its insulation could become damaged from heat and friction over time, and the switches can become more intermittent in their reliability as they are used.

Manuals describe replacing those switches as a fairly delicate procedure, possibly requiring special tool(s), so I suggest considering all your options before jumping into swapping them out.

Here's what the Ford Factory service manual says about the operation of the Electronic Shift Control System:

"In operation, when either of the two switches in the Overhead Roof Console are depressed, the Electronic Control Module will analyze information from the transfer case Shift Position Sensor to verify its current position. It will also analyze input information from the Speed Sensor (inside the case) and the Clutch Interlock Switch (manual transmission) ...or Neutral Safety Switch (automatic transmission) .... If all the design conditions of the system are met, the Electronic Control Module will command the Electric Shift Motor to execute the desired function. After the shift takes place and the motor is turned off, the Electronic Control Module will again look at the inputs from the Shift Position Sensor to determine if the transfer case is in the position that the operator selected. Finally, the Electronic Control Module will illuminate the pushbuttons in the Overhead Roof Console to indicate that the desired function has been completed."

I hope this helps you!

 

My 4x4 button wouldnt come on a week ago. I've had the truck for 3 years, and this is the first year it wouldnt work. It's and '86 Bronco2, auto 4x4(trash). Anyway, I thought I'd save some people a LOT of money. I pushed my 4x4 button last week, and the lights didnt come on....nothing happened! It's supposed to be a bad winter, so we put it in the shop. We thought the worst. They put it on a computer and ran through all tests. Turns out, there is a wire down in my dashboard by the motor thing (under the cover in the dash), just over the glovebox. In newer BII's, I guess there's and access to them behind the drivers seat *this may not apply to you*...The wire was cut and frayed really bad, it had come apart from what? I dont know. They put the wire back together and now it works again. Check for that wire. From what I understand, on mine it was Yellow. Look for it and be sure it's ok. Angel

 

OK I checked the shift control module thing in the dash this weekend. When you push the button, it lights up but does not blink. From reading on this forum, it sounds like my module is bad. Is this something I can get from the aftermarket or do I have to do to a stealership for it?

Thanks,
Brian

 

Could be the shift motor itself. Mine "died" shortly after I got the Ranger. I took it to a shop and they told me all I needed to do was give the shift motor a good cleaning. Here's how I did it:
It's really pretty simple. Undo the electrical conection and take off the shift motor by unscrewing a few bolts. There is also a bracket that will come off too. Take apart the motor assembly, (the larger cylinder shaped part). Be careful that the spring loaded contact brushes don't fly out and get lost while doing this. Spray it down reaaly good with some electrical connector cleaner and lube it up really good with a spray lube that will not freeze. I made that mistake and if the temp drops below zero I can't count on it working. I don't think you really need to worry about the gear part of it, (the smaller section of the shift motor that actually attatches to the transfer case.) You just want to make sure that you don't try turning the gears or anything because it will mess up is allignment and make it harder to reinstall it. It's been almost two years since I did mine and it's been fine since except like I said in super cold weather. Good luck.
I hope this helps. I have done it on my Ranger and a roomate's explorer, both successful, and has been 2 years now on mine with the only probelms being in extreme cold weather.

 

Thanks Adam,
Now correct me if I'm wrong but I didn't think it would be in the shift motor if I'm not getting solenoids to click or anything???
I thought I was checking the shift module this weekend, but as I read more it sounds like I should have disconnected two pigtails of wires before hitting the white button. I don't know if it matters, but I'll try that this evening.

 

I don't know for sure about the solenoids clicking. I think mine only made a clicking sound the first time it wouldn't work, after that it never made a sound. My roomates explorer didn't make any noise either. I know it is a very common problem with the shift motors because they are not well sealed and if the don't get used frequently they get stuck. Let us know if it works.

 

To test the shift module, there are 3 plugs on it. Disconnect the 2 that are plugged straight into the box, leave the one that is pigtailed into the box plugged in, and push the white button. It should do some kind of self test. If the light doesnt come on at all or stays on solid, something is wrong with the wiring. Our light didnt come on at all, and then we found out that there was something wrong with the wiring. Call your nearest tranny shop, and they should be able to test it pretty cheap. It'll save a lot of headaches. I wish you luck. Merry Xmas!! Angel

 

Thanks Angel,
I'll be trying that in about 90 minutes : )

 

Hi folks, me again. I checked the shift module again last night. This time I actually unplugged the correct wires and the light flashed. Looks like I'm back to looking for a fuse or that fusible link.