1994 Jimmy 4x4 Problems - 4hi inop

[84hurst]

Well, I searched for 40 pages and cannot seem to find a solution to my problem. The link that I've followed a few times is only for 1998 and up and will not apply to my problem. I own a 1994 GMC S15 Jimmy with the 2 button switch on the left side of the dash. The truck will not engage 4hi at all, not in any gear, not moving, not standing still. 4lo works great, but sometimes both 4hi and 4lo lights light up when engaged. When I push the 4hi button, I can hear the transfer case making a noise (I assume the motor is attempting to engage 4hi). Both the 4hi and 4lo lights will flash a few times but with no 4x4 engagement. I checked for codes and found none. I checked the accuator under the battery but I'm not sure if it is good or not. I am able to move it by hand approximately 1/8-1/4. Is this normal or it supposed to move more? I've heard that its possible for the cable coming off the accuator to seize up but I would like to know for sure. There is vacuum at the accuator, so I do not believe there is a vacuum issue here. Are there any common problems, describing my exact symptoms, that I can look into? Thanks in advance. Jeff

[blazes9395]

The electronic transfer case on the 93 and up with the dash button are essentially the same as the newer ones. In your case and from what you describe, check you transfer case control motor and its connections. These units have a habit of having corroded connections and making them not work properly. If that checks out it could very well be the control unit located inside the truck. These can and do go bad causing problems too.

[84hurst]

Originally Posted by blazes9395

The electronic transfer case on the 93 and up with the dash button are essentially the same as the newer ones. In your case and from what you describe, check you transfer case control motor and its connections. These units have a habit of having corroded connections and making them not work properly. If that checks out it could very well be the control unit located inside the truck. These can and do go bad causing problems too.

Where is it located? I will look into it when I get back into town. Any particular wires I should look at that normally get corroded?

[blazes9395]

The transfer case control module is located on the passenger side of the dash, located under the glove box if I remember correctly. I think it piggy backs the ECM wich is located in the same spot, under the passenger side dash.

I would check the control motor first, maybe take it off the transfer case and clean it and make sure it looks clean. Check the connector too and clean it if need be and see what happens and go from there.

[MT-2500]

When it does not shift right how many time does the shift button light blink?

[MT-2500]

Grounding pin J on diagnostic connector should give a code if not shifting right.
Codes range from 1 -2 -3 and 4.
Post back code no if you cam get code.
And post back transfer case ID on back of transfer case.

[84hurst]

Originally Posted by MT-2500

When it does not shift right how many time does the shift button light blink?

The light blinks about 5 times I believe, but I'm out of town at the moment and won't be able to verify this til next week. As for the transfer case, I would assume that all the 94 GMC Jimmy's with the push button 4x4 will be the same. 233 I believe. I already tried to pull the codes and there were none stored.

[MT-2500]

Originally Posted by 84hurst

The light blinks about 5 times I believe, but I'm out of town at the moment and won't be able to verify this til next week. As for the transfer case, I would assume that all the 94 GMC Jimmy's with the push button 4x4 will be the same. 233 I believe. I already tried to pull the codes and there were none stored.

ID the transfer case.
And recheck for codes.
4 light blinks could be code 4.

Ther is no code 5 on them

[84hurst]

Originally Posted by MT-2500

ID the transfer case.
And recheck for codes.
4 light blinks could be code 4.

Ther is no code 5 on them

The light blinks about 5 times when when I try to engage 4hi, not when I'm trying to pull codes.

[MT-2500]

Originally Posted by 84hurst

The light blinks about 5 times when when I try to engage 4hi, not when I'm trying to pull codes.

Pull codes and post back what you get.

[84hurst]

Well, finally got back to town and am working on the truck right now. There is a number 2 code stored. As I figured, this is the 233 tranfer case.

[MT-2500]

Originally Posted by 84hurst

Well, finally got back to town and am working on the truck right now. There is a number 2 code stored. As I figured, this is the 233 tranfer case.

Code 2 points to shift/encoder motor fault.

Check all wiring to it and if wiring is good you will need to replace the encoder motor.

I would suggest a factory repair manual or a All Data online sub for the wiring diagrams AND REPAIR FLOW CHART FOR CODE 2.

http://www.alldata.com/products/diy/index.html

LET US KNOW HOW IT GOES.

[84hurst]

It seems I need a subscription to alldata? Is there a step by step guide to determining the exact cause instead of buying a repair guide for $30? I'm laid off right now and don't really need to spend $ I don't have.