Blazer 4wd not working

[Nandy]

oka, so here we go again. To the best of my knowledge my 4wd worked fine before I took the Blazer to get the transmission fixed. Now it is not working. When I took the blazer to fix the transmission I mention to the owner of the shop that every time I tried to get off 4wd I had a big tump/bump when it disengaged and asked him to look at it if he could. At that time he told me the problem was the solenoid that is in the tirewell area under the battery that was a bit rusted and he told me to replace that. When I drove the blazer out of the shop he had set up the pump a bit too strong and it was pulling hard on the second. I mention it to him and he said to take it back and he will adjust it. Between that time and me taking it today I tried to use the 4wd and the lights change when I press the switched. I can hear clicking like relays but the front wheel drive dont engage at either 4wd hi or low. Idont feel/hear the tump/bump anymore. I mention it to him today when I took the blazer back and he told me my problem is that the 4wd switches need replacement or I have a blown fuse. Well, I can see the led in the switched light up when I make the changes although that on itself does not necessarily means the switch is ok as the led might be powered by something else. But I do hear the clicking of relays when I press the button and that is telling me that the switch is probably working. I checked the 4wd fuse in the side fuse panel and it is fine. Is there another fuse? Im starting to think he is just telling me something to get rid of me..
Anyway, any of you knowledgeable about 1999 4.3 4 door 4wd blazers care to discuss how the 4wd does work? I will pull the switch out if I can this weekend to test it with my DMM but what else do I need to be looking for? If I did that solenoid can I pull or push the cable and that should engage the 4wd? Any help appreciated...

 

[windsors03cobra]

Re: Blazer 4wd not working

Is the transfer case shifting ? If you put it in 4 LO does it shift into it ? If not you may have a shift motor problem, if the stupid lights and switches are behaving normal tho it sounds as if that problem may be in that ridiculous front axle disconnect and its related Vacuum ? actuator under the battery.


This is the exact reason I bought an my wife an AWD, buttons, lights and 4WD modules dont get ya through. My Jeep is a lever and the front axle is always locked with axle disconnect actuator to fail.
Good luck.

 

[mudslinging79]

Re: Blazer 4wd not working

those problems are why i go with manual transfer case and hubs.

 

[Bob_VT]

Re: Blazer 4wd not working

The actuator motors are a common fail in that particular vintage blazer. The motor itself needs to be checked to see if it is turning.

 

[dolluper]

Re: Blazer 4wd not working

Lights camera no action motor connections or motor BOB was quicker must be laucking around LOL's

 

[Nandy]

Re: Blazer 4wd not working

Ok, so I put it in towers and shift in to gear with the 4wd? So that vacum actuator, is it travels the same for 4wd lo than for 4wd hi? I wonder if I can pull/push it to engage the 4wd so I can isolate the trouble to it. I will assume in 2wd there is no vacuum applied to it and in any of the other 4wd there is vacuum?

 

[mudslinging79]

Re: Blazer 4wd not working

there is a company that makes a manual cable conversion deal so you can lose the vacume crap...

 

[Bob_VT]

Re: Blazer 4wd not working

Well the vacuum actuator (from what I recall) locked in the hubs but I though there was an electronic motor on the transfer that shifted it when there was an electronic button. I know the vacuum actuator was susceptible to freezing but often it was the motor on the transfer case........ I am having brain freeze I guess....dam it's cold!

 

[Nandy]

Re: Blazer 4wd not working

omg, I just typed a lengthly reply and lost it....
Anyway, reading around seems like the driver front tire is always connected to the front differential while the passenger side tire only connects when that actuator is on. So, I turn on the blazer in 2wd and shift to forward gear while stepping into the breaks and the transmission shift and feels "normal". Then I shift it to 4wd lo. I can hear the clicks inside the dash and a very noticeable clank outside. I shift to forward gear while stepping on the breaks the blazer really tried to take off. I drive the vehicle and it drives very differently (which is the way it did before the 4wd failing), it shift to 2nd gear at 5mph, 3rd at about 10mph but the front tires are not turning on their own. I then shift to 4wd hi and the feel is not much different from when it is on 2wd, not much to say there other than the front tires are not turning on their own. I park the blazer, choke the rear tires and jacked the passenger side tire. While the motor idles and it is set to 2wd the tire does not turn on its own but I can freely turn it with my hands. I then shift to 4wd hi and try the same. The front passenger tire will not turn on it's own and I can turn it freely with my hands, same results with the 4wd lo. That front passenger tire should lock when the 4wd is engaged, or so I have read... This leads me to believe that the TCCM is working fine but the actuator is not.
So, if I understand right, if the passenger front tire is not engaged with the front differential then neither front tire will turn because the passenger front tire is not connected to anything (if the actuator is not working) and the front differential is turning internally but without the passenger side tire resistance the other tire wont turn... Is that right?

 

[mudslinging79]

Re: Blazer 4wd not working

do you have limioted slip or lockers? cause if i were to lock both hubs and jack up 1 side, i will still be able to turn the tire in the air by hand. same thing may be happening with you... got stuck more than once in 4 wheel cause i tire wasnt getting traction

 

[windsors03cobra]

Re: Blazer 4wd not working

omg, I just typed a lengthly reply and lost it....
Anyway, reading around seems like the driver front tire is always connected to the front differential while the passenger side tire only connects when that actuator is on. So, I turn on the blazer in 2wd and shift to forward gear while stepping into the breaks and the transmission shift and feels "normal". Then I shift it to 4wd lo. I can hear the clicks inside the dash and a very noticeable clank outside. I shift to forward gear while stepping on the breaks the blazer really tried to take off. I drive the vehicle and it drives very differently (which is the way it did before the 4wd failing), it shift to 2nd gear at 5mph, 3rd at about 10mph but the front tires are not turning on their own. I then shift to 4wd hi and the feel is not much different from when it is on 2wd, not much to say there other than the front tires are not turning on their own. I park the blazer, choke the rear tires and jacked the passenger side tire. While the motor idles and it is set to 2wd the tire does not turn on its own but I can freely turn it with my hands. I then shift to 4wd hi and try the same. The front passenger tire will not turn on it's own and I can turn it freely with my hands, same results with the 4wd lo. That front passenger tire should lock when the 4wd is engaged, or so I have read... This leads me to believe that the TCCM is working fine but the actuator is not.
So, if I understand right, if the passenger front tire is not engaged with the front differential then neither front tire will turn because the passenger front tire is not connected to anything (if the actuator is not working) and the front differential is turning internally but without the passenger side tire resistance the other tire wont turn... Is that right?

Sounds like you tracked it down to that front axle actuator.
Manual operated inside the cab deal to make it right is like $200 or replace the factory stuff with whatever.....
http://www.4x4posi-lok.com/app_chevy-s.html

 

[royal0014]

Re: Blazer 4wd not working

Sounds like you tracked it down to that front axle actuator.
Manual operated inside the cab deal to make it right is like $200 or replace the factory stuff with whatever.....
http://www.4x4posi-lok.com/app_chevy-s.html

I've researched these, and it only replaces the vacuum actuator, BUT, it still uses the factory push/pull cable. Not worth my $200.


<<)))(((>>

 

[Nandy]

Re: Blazer 4wd not working

I think the cable thing is a good idea but a bit pricey. I will check the actuator this weekend if I can. I dont have need for the 4wd until next storm... Not that I am waiting till then.

 

[MTboatguy]

Re: Blazer 4wd not working

Have you checked all of your vacuum lines? I had a S-10 Many years ago, that would not go into 4wd and found out that one of the vacuum lines had been burned part way through, if your not getting full vacuum it will not completely engage.

 

[mudslinging79]

Re: Blazer 4wd not working

those reasons are why a lot of ford people are going back to manual hubs and transfer cases, may cost a bit at first but you know it works when you need it.

 

[Nandy]

Re: Blazer 4wd not working

Sure, let me know whats your address is so I can send you the bill.
I'm handy with tools, have fixed and maintenance every car I have so I see no reason to take it anywhere. If I can find how whatever works I can generally fix it. Most of the mechanics that I got in contact in the past has gotten me plenty of bad experiences and always let me thinking what was what they set loose so I had to go back. For exception of the transmission, which I was set to do it but had no time, I haven't use a mechanic in years. I know they are good and honorable mechanics out there but they are hard to find...

 

[Nandy]

Re: Blazer 4wd not working

Well, I needed my 4wd today to get my camper from the back of the house so I finally checked the actuator... The mechanic left the hose to the actuator off... Hooked it and working... So the mystery is no more.... Thanks everyone!

 

[kenmyfam]

Re: Blazer 4wd not working

Got into this one a bit late I see. Glad you found the issue. Do you have a manual for the Blazer ??? I still got mine for the 1998 Jimmy we got rid of last year. No use to me anymore.

 

[Nandy]

Re: Blazer 4wd not working

I have the book but it is useles for 4wd and transmission stuff.

 

[MTboatguy]

Re: Blazer 4wd not working

Unless you have the particular sub section factory manual for some of the GM products, they are pretty weak manuals, I know with the Chilton and other various aftermarket manuals, there is very little mention of how the 4wd works..