Threr are no lights on the 4X4 control on the dash

SCOOTER747

MEMBER
2000 CHEVROLET BLAZER
6 CYL
4WD
AUTOMATIC
125,000 MILES

I have replaced the transmission, transfer case, trans. Case switch motor, trans. Case control module, trans. Case switch, the plug-in on the t.C. Control motor because of a broken wire. The problem is the 4x4 still doesn't work. Threr are no lights on the 4x4 control on the dash, the fuses all seem to be good. When the mechanic finished replacing everything he took it for a test drive. While crossing railroad tracks in the road (not a rough crossing) the blazer dropped into low range that was when they found broken wire on the trans. Case switch motor (the big plug-in). Now there are no lights on the control panel on the dash and the 4x4 does not work at all. PLEASE HELP

3 Replies

RACEFAN966

MECHANIC
5,029 POSTS

Well we will need to do some tests to see what is going on. First I need you to make a jumper wire so we can run a test on the system. Now I need you to find the TCCM (transfer case control module) located under the dash on steering column bracket. Now use the jumper wire to jump between the orange wire or term 13 and ground. Now turn the key on engine off. Now note the blinks of the 4wd lights. If all 4wd lights blink only once and stop then there are no codes stored. Now the way it work is as such. If there are codes it will blink them to you. If it is code 1 it will blink once and pause 3 seconds and blink once again. If there is a code 2 then it will blink twice and pause 3 seconds and then blink twice again. So get me the codes and we will see that the TCCM can tell us. After you get the codes if there are any I would like you to pull the 4wd fuse (15amp) in the under hood fuse box for 40 seconds then replace fuse and then cycle the key on and off (do start engine) 5 times and this will clear the codes. Let me know what you find.