If shift motor is bad, will that prevent my 4x4 lights from coming on at startup

[jco77on]

I've been reading through piles of "my 4x4 doesn't work" posts, and haven't seen a definitive answer to this question. If my shift motor is bad, will that prevent my 4x4 lights from coming on at startup and also prevent my switch from lighting?

-I did the self test on the control module and it said it was good.
-I have no 4x4 lights when I start the truck.
-I have no lights at the 4x4 switch panel when the buttons are pressed.
-When I hit 4HI I can hear a relay at the CM, but it doesn't actually shift.
-I tore down the transfer case motor and the rubber stop bushing on the bottom of the gear was destroyed.

I'm going to pull the dash and check the switch out tonight, and hopefully find something to replace that rubber bushing on the transfer case motor.

I'll also be trying to follow this guide once I get my hands on a meter. But isn't this just to check the CM which is supposedly good from it's own self test? http://www.therangerstation.com/tech_library/4wd_control_module.html

Any helpful hints?

Oh, 1989 Ranger. 2.9L - 6 cylinder. Auto trans. Auto hubs. The guy I bought it from said the truck was barely driven the last two years.

 

[bigdan002001]

Could just be the bulbs needing replaced in dash?
The lights on the dash are controlled from the GEM module. Also check fuses in interior fuse block to make sure all 4x4 fuses and also GEM fuses are ok and good to go. Hope that helps.

Dan

 

[jco77on]

I thought that, but no switch lights (hi or lo) and no dash lights... The odds of all those being bad seems pretty unlikely. Also, I replaced the shift motor stop bushing and still no dice. No lights, no transfer case movement. Just a relay clicking at the control module when I push the 4x4 hi or lo.

 

[bigdan002001]

Mine used to not light up at startup nor would 4X4 low engage....found a fuse was missing for GEM module (there are like 2 or 3) replaced fuse and lights starting working at startup again and 4x4 low started working again. However my dash lights worked when it was shifted into 4x4 prior to replacing fuse just didn't light up at startup like it was supposed to. When you first start the truck the GEM runs diagnostics on 4x4 system, thus the lights coming on momentarily. I ended up swapping out for a manual t-case cause got tired of electrical unreliablity.

Dan

 

[bigdan002001]

Plus it's not all that unrealistic...it is a 25 year old truck....

Dan

 

[jco77on]

I checked the two fuses (one under the hood and one under the dash) and they were good. I was hoping it would be that easy, haha.

I'm wondering, after replacing that bump stop in the shift motor do I need to disconnect the battery to let the computer reset and "forget" that there was an issue with that shift motor?

 

[jco77on]

Thanks for the ideas btw

 

[bigdan002001]

No problem..my truck has 2 fuses for 4x4 and like 2 or 3 just for GEM system. I would almost be willing to bet it is shift motor. Easiest thing would be to apply power to the proper terminals down at tcase and see if motor turns when outside 12 V power is applied. I cant remember off hand which color wire controls what but i searched forums before and found that info. If power is supplied to motor and nothing happens then time for a new motor. If it turns then have to find out why power isnt coming from above.
Dan

 

[Snoranger]

Bigdan... There is absolutely no way his problem could be a GEM issue on an '89. It doesn't have a GEM.

 

[4x4junkie]

If the sensor contacts are not lined up properly, that can cause the system to go into shutdown (no lights or response from it whatsoever).

Did you make sure to put the cover back on the shift motor exactly where it was before?

 

[jco77on]

Yep, I marked exactly where everything was facing as I took it apart to make sure it went back together the same.

 

[jco77on]

So here's the latest..

Going through the 4x4 troubleshooting guide on here I now know that

-My 4x4 selector switch is good and
-My lights all work (button and dash)

Replaced the shift motor.

So... Switch is good, indicator bulbs are good, new shift motor, shift module passes self test..... But when I turn on the truck, 4x4 lights do not temporarily come on (check engine and battery lights do). When I push the 4hi select I hear the shift module relay click, but that's all. No 4x4 lights and no shift motor movement.

 

[4x4junkie]

So you get the light flashing during the self-test?

Sounds like there could be an issue in your wiring then.
There's also a possibility the module itself could be bad and the self-test not detecting it, though at this point I'm not sure if I'd keep throwing parts at it... I'd probably just say to heck with it and swap a manual-shift case in there.

 

[jco77on]

Yeah, the old module was "passing" it's self test. I had voltage going in to the computer but not at the shift motor, so I got another shift computer from ebay. I ohmed the wires going from the shift computer to the shift motor and they were good. Fingers crossed..

 

[jco77on]

Fixed it. Apparently I'm the 1 in a million where it actually was the shift computer. Replaced that and it works as it should.