Crud - first blizzard and 4X4 not working

rstackjd · 12-01-2006, 08:05 AM

I'm had my 2000 Blazer ZR2 for a few months now. Never tried out the 4X4 (should have I know) and when I went to engage it this morning the 4HI light flashes but then stops flashing and goes out. When I try 4LO it doesn't even flash

Any trouble shooting advice? I've already checked the fuse (is there more than one - I checked the one in the panel to the left of the dash) and it is fine.

Thanks

EDIT - Sorry - just realized this should be in tech - new guy here D'oh

Blue Bowtie · 12-01-2006, 05:47 PM

Did you find the Tech Article posted about the 4WD/AWD system?

Look here:

http://www.automotiveforums.com/vbul...d.php?t=572914

laxman21 · 12-01-2006, 08:24 PM

could be the front vacuum switch.

Blue Bowtie · 12-01-2006, 08:33 PM

The "switch" is usually a solenoid valve mounted to the cowl. The vacuum actuators can fail or loose a hose connection as well. They hose is routed in a convoluted tube near the exhaust, and tends to get baked a bit.

The real switch which detects whether the front diffy is locked is right on the differential case.

Oddly, I just had a 2000 Jimmy in today for a non-fuctioning acutator. Go figure. Think it had anything to do with the 13" of snow?

laxman21 · 12-01-2006, 09:14 PM

Quote:

Originally Posted by Blue Bowtie

The "switch" is usually a solenoid valve mounted to the cowl. The vacuum actuators can fail or loose a hose connection as well. They hose is routed in a convoluted tube near the exhaust, and tends to get baked a bit.

The real switch which detects whether the front diffy is locked is right on the differential case.

Oddly, I just had a 2000 Jimmy in today for a non-fuctioning acutator. Go figure. Think it had anything to do with the 13" of snow?

I stand corrected!

What type of shop do you work at?

Blue Bowtie · 12-01-2006, 09:48 PM

My four-stall garage.

rstackjd · 12-01-2006, 10:02 PM

I;ve looked at the tech articles and tried the easy fix (disconnect the battary to reset the the computer) - no luck. Hopefully tomorrow the weather will be a little nicer and I can look at the hoses etc. (sucks working outside in this climate)

I did notice that when I press the 4HI button I can hear a clikcing sound that seems like its coming from under the center counsel - not entirely sure whether thats good or bad

Thanks guys

mike2004tct · 12-02-2006, 08:44 AM

Quote:

Originally Posted by rstackjd

I;ve looked at the tech articles and tried the easy fix (disconnect the battary to reset the the computer) - no luck. Hopefully tomorrow the weather will be a little nicer and I can look at the hoses etc. (sucks working outside in this climate)

I did notice that when I press the 4HI button I can hear a clikcing sound that seems like its coming from under the center counsel - not entirely sure whether thats good or bad

Thanks guys

That sounds like a good sign that your actuator is at least trying to work.
A friend of mine had a vacuum problem with a '98 S10 that has the same setup as my '97,he had a craked hose, so take a look at this; From the vacuum ball mounted on the left side of the hood(might be on the fender on yours) , follow the small hose to where it "T"s off at the throttle body. 1 hose to the TB, another hose goes down to the transfer case.

rstackjd · 12-02-2006, 11:24 AM

Quote:

Originally Posted by mike2004tct

That sounds like a good sign that your actuator is at least trying to work.
A friend of mine had a vacuum problem with a '98 S10 that has the same setup as my '97,he had a craked hose, so take a look at this; From the vacuum ball mounted on the left side of the hood(might be on the fender on yours) , follow the small hose to where it "T"s off at the throttle body. 1 hose to the TB, another hose goes down to the transfer case.

thanks Mike - I'll try that. So are you thinking that the actuator is ok but there's just not enough "umph" in the vacuum, possibly due to a leak? Remember - I'm a mechanical "short bus" rider!

Vette all put up for the Winter? I saw a C5 vert on the road in Hartland this moring!

mike2004tct · 12-02-2006, 04:35 PM

Quote:

Originally Posted by rstackjd

thanks Mike - I'll try that. So are you thinking that the actuator is ok but there's just not enough "umph" in the vacuum, possibly due to a leak? Remember - I'm a mechanical "short bus" rider!

Vette all put up for the Winter? I saw a C5 vert on the road in Hartland this moring!

Yes to the umph question, I personally had it happen with a '88 S10 many years ago, just a disconnected vacuum hose. No vacuum, no 4WD. I actually took it back to the dealer I bought it from, because I got caught in a snow storm without 4WD. Was I embarassed when they told me "Just an unconnected hose.
At least, it was a "No Charge"

Hope it's that simple for you.

Yes to put up for the winter also. Drove it over to the storage garage last weekend when it was 60 and sunny.

Come on April.
Mike

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