4wd indicator blinking

98 burb with pushbutton 4wd. When I select anything but 2wd the indicator light for the selection just blinks. Never turns steady. Anything common? Worked fine last week big snowstorm here yesterday and now this. the front
wheels do seem to engage in 4 hi even though the light is blinking. If in 4 auto if the rear wheels spin the lamp goes out and sends it back to 4 auto. My scan tool ispicking up no DTC's but it's not a real high end unit. Anything quick I can look for? Larry
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jdoe wrote:

Usually it's an indication that the transfer case is not shifting into the range or the front diff is not locking up. With our Tech 2, we can check things like what position the t/case actually is in....and whether the front is locked up. You may not be able to get that type of data with yours, but if you can, I'd be looking thru the data.
Ian
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Borrowed my buddy's matco mentor. Was able to see the data streams with it. Shows front axle not engaging but everything else normal. Followed the diagnostic in the service manual (gm not chilton) and everything seemed to point to the front axle actuator. Got under it (messy due to the snow storm) and sure enough the actuuator did not work so I got a new one to no help. Gonna run more tests but it seems like the module is about the only thing left. I did check all fuses first btw. Darn thing worked fine last week coming back from MN in the ice storm there than we get big snow and I'm stuck with a 4x4 that ain't :-( Larry

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jdoe wrote:

If you threw a new actuator in and it still doesn't work (which was a bad idea, should have properly diagnosed the problem), you definitely need to start by figuring out if you are getting the proper power and grounds at the actuator wiring harness connector. You might have something as simple as a broken wire.
Ian
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Ian Here is the rundown to this point. I tried the actuator based on the GM troubleshooting guide in the manual. I decided to pull the selector out and check for cold solder joints. There were they were visibly cracked. So I resoldered and than the actuator was trying to work. Figured I'd recheck and found one more bad joint and repaired. Than the actuator came out (4wd position) but would not go back in. Figuring it may need to be under presuure I installed it and the truck would sometimes go into four wheel. Just before it would "lock up" into 4wd there would be a strange screeching noise. NOt sure what but this was at low speed driving around my block 20 to 25 mph. So I parked it and hooked up my friends scanner (wanted to see if it would go to front axle locked). Well now it would not go back to solid light and would occasionally make the noise so I'm at the end of my rope with it. I did run through the voltage checks called for in the manual also. Any further ideas? Thanks for help to this point. Larry

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First step would be to check the tcase and 4x4 fuses

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First thing I did. Larry

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