Stuck in 4 Lo

[nickkendall]

ok so i can plug the encoder back in and lights still on and it does not work would i be able to scan it with it just hooked up and not installed on the case itself as i can't seem to get it to line back up would they still b able to scan it and tell?
does the encoder motor actually have a computer part in it? i see it has 2 plugs with alot of wires so does that someone tell the switch to light up?
i was using a test light on one of the plugs that goes to the motor and i was getting power to at least 1 of the wires in the plug that goes directly to the motor and when i put the test light on and was messing with it the actuator started turning and the switch lit up but at that time i only had 1 of the wiring plugs hooked up and a test light on the other...any ideas?

 

[SunlitComet]

I think you can leave it removed from the case but the plugs must be connected. I cannot ber positive it will give the correct error later. DO NOT do the test light thing on the motor you will screw up a damaged motor even more. And the reason I say damaged is becuase when you did that test light thing without energizing the lock release you just broke the assembly or it was already broken. For the motor to turn the brake must be powered to unlock so if you did not power the brake release and motor at the same time it is broke in at least one way. Your shift motor assembly needs to be chucked.

So now that you have to replace a part now make sure your tcase is in 2wd go under the hood and pull the ATC(automatic transfer case) 20 amp fuse and put a new shift motor/encoder assembly on the case. Plug it in and reinsert the fuse then test your system. It is possible you may have self discovered your own problem maybe. If that was the problem the service light should disapeer shortly.

The encoder part is basically on/off switches. Depending on which ones are on/off the controller uses that data to determine where the position of the shift shaft.

 

[nickkendall]

well hopefully the shift motor was the problem since i need a new 1 anyways
since i did have the dash indicator working when i had the actuator unhooked on a plug and the test light on it.. so i guess i will be ordering a new 1 2morow
thanks for all the help

 

[nickkendall]

ok im back at it after ordering the wrong unit and finally got it straight....i put on the new actuator and the lights all light up and it seemed to shift through the gears a time or two and then i went to put it in 4lo it says it is but it is not 4 low it seems to be 2 high but now it wont shift out and when i push the buttons i hear a clicking noise coming from the dash and the light just blinks and goes back to 4lo?? any ideas?

 

[SunlitComet]

If you are sure on ther application of the shift motor/encoder them only two possibilities. Either the tccm or the transfer case internal is obstructing shift and the tccm is interpreting this as a bad SHift motor assembly. Kill all the battery power and ignition power to the tccm and try again. What happens? Every detail helps. The clicking noise are the motor relays working in the tccm.

 

[nickkendall]

thank you for all your help...i will try and unhook battery and see if that helps at all...

 

[nickkendall]

i unhooked the battery for an hour hooked it back up and it is back in 2 hi it also allows me to go into auto 4..but it doesn't actually work still only 2..it does not go into 4 hi or low....could i have gotten it lined up wrong somehow?

---------- Post added at 03:13 PM ---------- Previous post was at 03:12 PM ----------

my service 4 wheel drive light has gone out

---------- Post added at 03:35 PM ---------- Previous post was at 03:13 PM ----------

ok we went and when u push the button from 2hi into 4 auto you can hear the actuator on the front axle move and you can hear a click in the encoder motor it will only go from 2 hi into 4 auto

 

[SunlitComet]

No line up problems.

Following the owners manual below can you command a neutral T-case?

If so then you should at least get 4lo as well unless the tccm or case is screwed.

If not try the link below. Without a scanner you can still disconnect the mode switch ohm those specified wires while you depress the buttons to see the if the reading are coming out right for the tccm to interpret. But that is as far as you can go without a scanner short of replacing your tccm and trying again. Anything beyond that busted wires or fuses is the t-case itself.

 

[nickkendall]

where is the link?

 

[SunlitComet]

http://www.sunlitcomet.com/pdf/automotive/tahoe/98-99/1999-Chevy-Tahoe-ModeSwitchInoperative.pdf