Still stumped by this 4wd system on my 98 Blazer, was working then tried to use it one day just to use it and it would not engage. I hooked it up to a SnapOn Solus computer reader last night and no transmission / engine error codes came back.

I can press my 4hi or 4lo buttons and all I hear is a click coming from my TCCM, nothing more. If I unhook my battery, reset my computer and try it again, then after pressing either button, the light just blinks for a couples of seconds, makes a click like always then goes back to doing the same stuff. Any Ideas...

Which transfer case?
If a 233 you can not test with a scanner.
Does all button lights come on for a bulb check?
Ground pin 13 on diagnostic connector and read codes on the shift button lights.
They only give codes from 1-4
Post back any code no.

Have you checked all wiring and fuses?
http://www.automotiveforums.com/vbulletin/showthread.php?t=572914

I have the instatrak 243 unit I believe, 3 lights, no auto 4wd button.

Not done a bulb check, not extactly sure how to do that, but I do know if you press the lo or hi buttons they do blink but just for a split second. the 2hi light is on all the time.

When I ground 13, thne turn my key on, what lights will flash, I guess I just need to know what im looking for.

I have the instatrak 243 unit I believe, 3 lights, no auto 4wd button.

Not done a bulb check, not extactly sure how to do that, but I do know if you press the lo or hi buttons they do blink but just for a split second. the 2hi light is on all the time.

When I ground 13, thne turn my key on, what lights will flash, I guess I just need to know what im looking for.

What does the id tag on back of transfer case say?

When you first turn key on all shift buttons should light up for a bulb check.
Do they do that?

The code will be flashed on shift button with a 233 transfer case.

After grounding pin 13 out here is my findings:

turn the key on and all three lights came on during the bulb test ok, and also with the pin not grounded out.

Codes as follows:

All three lights came on, very short pause, back on, short pause again, then back on, so three flashes in total with all three lights..... then about 5 seconds later, the same pattern.

Also, not sure what all the codes are, but just in general, I have looked all over sites like autozone, napa, etc trying to find the tccm... can't find it, what do they call it and what would it be under?

Also, not sure what all the codes are, but just in general, I have looked all over sites like autozone, napa, etc trying to find the tccm... can't find it, what do they call it and what would it be under?


A code 3 is the shift motor or circuit problem.
Check all wiring and power feeds and grounsd to shift motor.
Also remove shift motor and see if the shift lever can be turned with a wrench.

For proper testing and wiring diagrams I would suggest a good factory repair manual or a all data sub.

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

I signed up for alldata.com, pretty nice little site for only 25, combined with a hayes manual, thats some good stuff...

what kinf of voltages should I be looking for when I unhook the connector from my transfer case motor and have someone pushing the buttons? I guess I will pin a ground then go to every pin in the connector to see what I have?

Howdy,

Had the same problem on my 98. The problem is with an electronic box hidden by the passenger side kick panel. If you open the passenger side door and pull off the passenger side kick panel(may have to remove floor mats) there will be an electronic box in there. What I have to do to mine is unplug the one electronic connector that goes into the box. This should be done with the KEY ON, engine off. Then plug it back in with the KEY ON, engine off. Try pushing the 4X4 buttons with the KEY ON engine off. You should hear the drive shaft engaging. This should fix it.

In order for the connector to stay plugged into the electronic box, I wrapped duct tape around the connector and taped it to the electronic box to hold the connector in place. Don't be surprised that you will have to do this procedure again......I have to do it at least once a year on mine. But it does work for quite a while.

I will try that, all I hear is that box down ther "Clunking" lol

Is the connector im looking for on the t/c motor, does it have a screw going threw the center of it? wonder what the voltage is suppose to be on the pins...