Chevrolet Repair: 1988 chevy 4x4, chevy 4x4, electric solenoid

Question
QUESTION: I have boughten a 1988 k1500 chevy 4x4. My problem is when I put it in 4 wheel drive my voltage gauge drops for a few seconds and than my gauge fuse blows and the 4wheel does not engage. I tried 4low the rear end goes to low gear but 4wheel still doesn't work. Any ideas as to what might cause this. Thanks for your time.  Rusty from minnesota

ANSWER: HI RUSTY ,I WILL ASSUME THIS IS A ELECTRIC 4WD PUSH BUTTON AND NOT THE FLOOR MOUNTED SHIFTER.. THIS SOUNDS LIKE THE ACTUATOR IS SHORTING OUT CAUSING THE VOLTAGE TO DROP BECAUSE OF THE SHORTED OUT MOTOR..THE FUSE THAT POWERS THIS IS MORE THEN LIKELY ON THE GAUGE CIRCUIT..I WOULD SUGGEST YOU REMOVE THE WIRING HARNESS TO THE ACTUATOR ON THE TRANSFER CASE AND THEN PUT IT IN 4WD [WHICH IT WILL NOT DO] BUT LETS SEE IF THE FUSE POPS AND THE VOLTAGE DROPS..IF ALL IS OK I WOULD THINK THE ACTUATOR MOTOR IS JUST SHORTED OUT. THIS IS WHAT LOCKS THE TRANSFER CASE IN 4WD AND SENDS POWER TO THE FRONT AXLE TO LOCK IT IN..LET ME KNOW HOW THIS GOES AND GET BACK TO ME IF NEED BE.
GOOD LUCK TO YOU,,,TOM

---------- FOLLOW-UP ----------

QUESTION: It is a floor shifter. Could it still be the acuator? And thanks for the fast response.

Answer
HI RUSTY AGAIN,THIS WILL NOT HAVE A ACTUATOR FOR THE TRANSFER CASE IF IT HAS A FLOOR MOUNTED SHIFTER..BUT WHAT IT DOES HAVE IS THE MOTOR THAT LOCKS THE FRONT 2 AXLES TO EACH OTHER...I FORGOT WHAT YEAR THEY WERE THAT HAD ELECTRIC SOLENOID OR VACUUM..LOOK AT THE PASS SIDE FRONT AXLE AND SEE IF THERE IS A VACUUM DASH POT OR ELECTRIC SOLENOID,IF ELECTRIC REMOVE THE HARNESS TO IT AND TRY TO PUT IT IN 4WD LIKE THIS AND SEE IF THE FUSE POPS AND GAUGE DROPS..IF NOT I SUSPECT THIS SOLENOID IS BAD,,SHORTING OUT,,OR WIRE HARNESS PROBLEM..LET ME KNOW,,TOM.