i have a 2000 blazer .i havent had it long..
first ice storm today i figured i give 4 wheel drive a try. i dont think its working!
i tied the 4x4 when i first got it,i stopped in a gravel parking lot,pushed teh 4x4 hi button,it flashed then went solid on hi 4x4. i stepped on the gas and seemed all 4 tires were spinning. hit 2x hi button and drove back home.
well today ,like i said we got ice. going down the road i pressed 4x4 hi and it just flashed. wife read the book going sown the road and it said you have to be stopped in nuetral. so we pulled over and tried it,waited 30 or so seconds and just flashes. tried hi and low a few times. i got it to go to low,but dont believe all 4 wheels are pulling,seemed to be in low cause we were going 40 and 3500rpm, stopped and hit 2x hi and it drove normal. what should i check into first? could everything be froze?what is this 13 pin connector i been reading about and does it apply to this year model or do i need to check with a scan tool? no check engine or service 4x4 lights are on.

 

NEVER GO ABOVE 20MPH IN 4LO, IT WILL DAMAGE YOUR TRANSFER CASE. to understand your "problem" you have to understand what gm and other companys define 4wd as. the blazer has 4wd. only 2 of the 4 wheels spin in 4wd. in the rear 1 wheel spins in 2hi and is your drive tire. they do this to decrease the wear on tires, gears and to reduce turning radius. in 4wd hi the front left and rear right tire spin. this is "4wd". you have 4 tires in contact with the road, but 2 drive tires. understand? to engage 4hi you have to be moving any speed under 40mph. to engage 4lo you can be in drive but going less than 3mph or in neutral. try this and see if you still have a "4wd problem". let me know

 

You should start by disconnecting the TCCM (located behind the passenger side kick panel) and checking the connections for corrosion. Clean them as necessary.

If you have the 3-button switch on the dash, check out the OBD2 Non-Automatic Transfer Case Diagnosis thread in the Tech Article (DIY) section for instructions on pulling codes from the TCCM and what each code means. You may have an encoder fault that is prohibiting the engagement of 4HI or making it intermittent.

I'm not sure where you heard that from, but you won't damage your transfer case going over 20mph in 4LO. You can only go so fast in 4LO due to the gear reduction and you have to keep track of your gauges when doing so (low speed plus high rpm may cause cooling issues), but there is no problem running faster than 20mph in 4LO.

 

according to the gm manual they say never go about 20mph, so idk as far as how it would effect it but when they say it in CAPS it usually mean its important.

 

That doesn't mean it will damage your transfer case now does it. The reason it is stated in there is because at speeds in excess of 20mph, the benefits of 4LO are pretty much moot. It is a pretty good leap to go from a warning in the manual to it damaging your transfer case. But you would have to understand how the transfer case works to know why it wouldn't damage a thing provided you keep track of your gauges as I have stated.

 

as long as you keep an eye on that temp gauge(tranny if you have it). they might have put that in there to for a warning about overheating the tranny. because 4 lo gears the transmission down so i understand where it can only go so fast,but your truck is working alot harder to give you the torque of 4lo and the speed you're trying to reach.

 

Isn't that what I said?... You just don't know when to stop...

 

yeah.

 

it got up in the 30s yesterday driving around it seemed to be engaging. it was kinda hard to make sharp turns in the parking lot with 4x4 engaged