When I push the botton for four wheel drive high, the lights flash, but then clicks back into 2 wheel drive. Four wheel drive works though. its a 1995 Jimmy

Check the lever if is connected to the gearbox

It sounds more like a bad actuator/valve

I’m happy to assist further over the phone at https://www.6ya.com/expert/brock_d67526d2a834c47e

no year?
never drive, part time 4wd on pavement, unless said pavement
is ice or snow covered.
only AWD allows pavement (tires direct upon) driviing.
part time 4wd is for offroad , off pavement driving,
this is because 4wd has no center differential.
http://en.wikipedia.org/wiki/Four-wheel_drive

and with out such, winds up the drive line fast. and breaks it.

wiki states (no year stated by you)
Part-time four-wheel drive was standard on all models. to 1991
then came
ActivTrak 4WD
cept
4H (high-range full time four-wheel drive), 4HLc (high-range four-wheel drive with locked center differential) and 4LLc (low-range four-wheel drive with locked center differential
so do not use LOCKED on pavement. on active track. only 4H
the wiki states the Super-select is retained 2006 to present.
Super-Select 4WD II

read the glove box manual under 4wd

you need to stop both front wheels from turning to see if 4 wd is working
just stopping one side means nothing as the diff action is operating and making the opposite wheel go faster

Sometimes the solenoids will stick on the axle neither in 2 or 4 wheel drive, if this problem started when you weren't shifting between two and four wheel drive it is probably the push button switch cluster on your dash going bad

sounds like the shift motor on the transfer case is going bad.

there is a sensor on the tranny or transfer case that may have gone out check this and you may have a quick fix

the transfer case is sticking from non use, change the lube in the case ( Ford ATF) and drive it for awhile it should be ok then.

if it is electronic there is probably something wrong with the wiring..

but if it is manual...it might be the actuator........

Your blazer is equipped with a shift on the fly four wheel drive. That means that at speeds less than fifteen miles per hour you can shift into or out of four wheel drive by simply pushing the four wheel high button. If you wish to shift into four wheel low. Stop, put the transmission into park or neutral, and push the four wheel low button. Same procedure for shifting back out. Never shift into or out of four wheel low while moving. And be careful in four wheel low. At full throttle your still barely moving, you don't want to blow your engine up!