2wd light wont light and 4wd low light blinks constantly

It sounds like you are experiencing an issue with the 4WD system on your 2001 Chevrolet Blazer. Here are a few things you can try to troubleshoot the problem:

1. Check the fluid levels in the transfer case and the front and rear differentials. Low fluid levels can cause issues with the 4WD system.
2. Make sure that the front and rear driveshafts are properly connected and not damaged.
3. Inspect the 4WD control module and wiring for any damage or lose connections.
4. Check for any error codes using a diagnostic scan tool. This may help to identify any issues with the 4WD system.
5. If the issue persists, it may be necessary to have the 4WD system inspected and repaired by a professional mechanic.

I hope this helps! If you have any additional questions or need further assistance, don't hesitate to ask

no year car, and matters huge, 1993-2023 up.
they are not ALL the same
no country told
no engine size told or even gas and diesel.
4wd or 2wd, yes low range 4wd.
do not use the 4wd, with 4wd mode set to LOCKED on pavement
not told engine runs. ok, : guess#1 yes
car drives ok in 2wd, in all gears PRNDL, R, D and L????
car fails in 4wd only if yes, say so and tell what 4wd mode it is in
4wd full time 4wc, part time or 4wd lock mode.

sorry we can not guess year,. and 29 long years of evolution on this car, no YEAR told.
AWD called, ALL time 1999, and before that was Select track 1993 first one

did kids play with 4WD levers? seems so to me.
put it 2wd , and learn how to use 4wd later. (ASK),

Some Chrysler ,Jeep and Dodge vehicles have ttye pressure sensors calibrated to the vevicle,so therefore if you change the
tyres to a different type you will need to take your vehicle to a C.J.D.
service department to have the computer of your car re-programmed to accept the new tyres

Replace the motor/module on the transfercase. It has an internal short. Don't replace it. Soon you will have to replace or rebuild the transfer case and the motor.

Check the vacuum switch under the hood in the center of the firewall...follow vac diag

for 4wl need to be stopped and put in neutral or park it wont actuate while driving [ blinking light indicates failure to engage ] 4wd hi can do while driving --if fails also then check and test for actuator sticking --control module --or transfer case failure

THE TRANSFER CASE MOTOR IS ONLY FOR 4WD LOW. That would have never been the problem as soon as you confirmed it shifted into 4wd Low. 2wd and 4 Hi work off of vacuum. You may have one or two issues. A vacuum leak up by the front axle that engages the 4wd HI or the sensors on the transfer case.

gm has had a lot of problems with the button switch on the dash id start there

probably a bad 4wd switch have it checked I had sort of the same problem after dealer put factory fog lights in shorted out 4wd switch

check switch , fuse and relay if good check cable hoses and wiring at transfer are not damaged or disconnected -check actuator for proper movement actuator has a tendency to stick lube actuator rod if necessary