Stuck In 4 Hi

[Mouldy]

hey there,
1st I just want to say thanks to everyone on this site! you've helped me out of a couple of jams in the past.

1st post here so hopefully someone can help me solve this mess

been running in 4 hi for the last week or so as we got a huge dump of snow even switched to 4 lo a couple times working like a charm....until

yesterday ran the wife to work and went to switch to 2 hi (main roads are clear of snow now) lights went off but...
still in 4 hi...ok got home started lookin at stuff ..had some clicks ,ECM
light would go on and off after resetting ECM with switch ...tapping dash switches click click,,,no changes..then ecm would not reset..or the light wouldnt turn on again...started getting strange signs like dash lights come on then slowly dim...dash lights come on...(both hi and low lights) they go out when i depress clutch or press dash button..then come back on..all this stuff is intermitten ..some times they go on..sometimes they dont..just weird

i went to test the ecm using that great how to..and the ecm light dont light up at all... i have power ..and i have ground on the 8 pin pigtail
i found a used ecm for cheap and thought what the hell..buddy assured me it works...but same result

i have power at three of the wires at the dash switch (4 including the one that powers the dash light inside the switch from the parking light circuit)
and power at 2 of the conectors on the lower 5 wire plug on the front of the ECM. good power and ground on the 8 pin pigtail..

my ranger is a 91 with auto everything (electronic) dash buttons hubs tcase etc

hopefully this novel (sorry) has provided enough info

to me it feels like there is a short/open (bad ground or something) in there somewhere but what bugs me is that the ecm wont light up at all and im 99% sure i have 2 good ones ..i would move on to the switch diagnosis or even the motor but i seem to be stuck at the ECM

Thanks
Rob aka Mouldy

 

[dogboy]

First of all, the ECM has nothing to do with the 4wd system. I get what you mean though, I think you are just talking about the 4wd computer.

I haven't looked at the computer testing write up in a while, but if I remember, you "should" be getting a little red light that flashs on the top if it is good.

When you say "tapping dash switches click click,,,no changes" are you meaning that when you push the 4wd button the relay/ computer makes a clicking noise, but nothing else happens, or that the botton itself makes a clicking noise?

If the computer is making the clicking noise, then I'm pretty sure it is good, and since the switch told it to shift, the switch is also good.
I would then look at the shift motor be taking it off (3 bolts on the back of the t-case), cleaning it, and inspecting it. There are quite a few things that can go wrong inside there.

It kind of sounds like your 4wd shift module/ computer is bad becuase you say you don't get the light. Which I would assume means the module is bad... But you say you've replaced it with a good one with the same results... Which would point ME towards the shift motor. Maybe it is not making a connection that allows the light on the module to light up?


If you have to have it out of 4wd, you can take the shift motor off of the back of the t-case (3 bolts) and manual turn the shaft to the indicated 2wd position using a pair of pliars. If I remember right, it should kind of "pop" into the spot/ hold itself there.


I hope that helps alittle bit.

 

[04 EDGE]

correct me if i am wrong but dont you need to shift the t case to 2wd then put the truck in reverse and roll back a few feet to disengage the front hubs?

 

[BlackBII]

correct me if i am wrong but dont you need to shift the t case to 2wd then put the truck in reverse and roll back a few feet to disengage the front hubs?

Yes, If he has Auto hubs.

After reading your post, I'm leaning towards the shift motor. If the module or switch went out, you usually don't get the 'clicking' when pushing on the buttons. Get under there and tap on the motor with a screw driver handle, and read this as well:
http://www.therangerstation.com/tech_library/TCaseshiftmotor.htm