Recently had abs module repaired due to abs pump running constantly and four wheel drive buttons just blinking when you push them...now abs motor is fixed but still get blinking when I hit any four wheel button...any ideas? 2001 blazer

 

The abs and 4wd are two separate systems. Check the vacuum actuator. On my '95 it's under the battery. Not sure on later models. Does the t-case shift into 4wd when you hit the button? With it in neutral, you should not be able to rotate the front driveshaft.

There are a butt-load of threads on here about the less than reliable 4x4 systems these trucks have. Do a lil searching, and I'm sure you'll find your solution.

 

There's several diagnosis threads here in the Tech Article section. You need to know whether you have the NV233 or NV236 transfer case. The NV233 will have a 3 button switch for the 4x4 and the NV236 will have a 4 button switch with autotrac. Start there, and post up more info about your trucks symptons and your results so we can help further. I would also start by checking the fuses for the 4x4 system.