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service 4wd light on


99church
10-24-2007, 01:34 AM
have a 99 blazer with np236 transfer case (4 button on dash,auto4wd,2hi,4hi,4lo).when i turn key on all the lights on the selector switch light up and go off, when i start truck, auto flashes, after i drive it a while it will settle on auto or 2hi. I am unable to press any of the selector buttons and shift to 4hi or 4lo or 2hi or auto.had the codes read and they were B2725 and C0367. i have pulled the atc fuse from the fuse box under the hood. i did this because sometimes, it felt as though it was in 4wd, but lights did not indicate that. i have replaced the 4 button selector switch, vac switch on firewall, front shift cable. still same problem when i plug fuse back in. constant service 4wd light. i can hear clicking underneath (encoder motor)and the tccm from inside, any help or words of wisdom greatly appreciated , thanks

MT-2500
10-24-2007, 08:45 AM
Was the codes cleared and did they come back?
The B code is for selector switch voltage or wiring circuit problem.
The C code 0367 is for front axel control circuit problem.

I would suggest you check the front axel circuit real close.
You will need a good factory repair manual info or a all data info on the repair flow chart for the codes.
You will need a real good volt/ohm meter.
Check all voltage readings as outlined in the repair flow charts for codes that were cleared and come back.
http://www.alldata.com/products/diy/index.html

Good luck
MT

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