4WD does not engage properly 1999 Blazer

[LJP_GURU]

I would like to use 4WD for the icy roads we have now and when I use the push button for 4-HI the light switches from 2WD to 4-HI but the front wheels seem not to be engaged. The rear wheels spin with the front not turning. Is this a transfer case problem and is this a costly repair?

[laxman21]

Originally Posted by LJP_GURU

I would like to use 4WD for the icy roads we have now and when I use the push button for 4-HI the light switches from 2WD to 4-HI but the front wheels seem not to be engaged. The rear wheels spin with the front not turning. Is this a transfer case problem and is this a costly repair?

Check the FAQ section.


Sounds like a vacuum problem to the front axle.

[LJP_GURU]

Pefect! I will check the FAQ section. Thanks

[laxman21]

Originally Posted by LJP_GURU

Pefect! I will check the FAQ section. Thanks

Sorry, I meant the "How To " section

http://www.automotiveforums.com/vbul...d.php?t=620747




and here is the threads:

http://www.automotiveforums.com/vbul...d.php?t=498812

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

[LJP_GURU]

Thanks for the links laxman! I had a read and looked at the pics very good info. I have a 99 also and I was wondering where on the firewall I could locate the vacuum switch you had a problem with. It is so bloody cold here and get dark so early right now and I would like to now if its easily accessible or the is a little digging to do. If is not easily accessible I might have to wait for a few day to warm up. Thanks for the post it was very helpful.

Also to mention my lights for 2WD and 4-HI do switch back and forth and I hear a little clunk but when I am on slippery surface only the rear wheels turn. My question is this the same symptoms your Blazer had?

[laxman21]

Originally Posted by LJP_GURU

Thanks for the links laxman! I had a read and looked at the pics very good info. I have a 99 also and I was wondering where on the firewall I could locate the vacuum switch you had a problem with. It is so bloody cold here and get dark so early right now and I would like to now if its easily accessible or the is a little digging to do. If is not easily accessible I might have to wait for a few day to warm up. Thanks for the post it was very helpful.

Also to mention my lights for 2WD and 4-HI do switch back and forth and I hear a little clunk but when I am on slippery surface only the rear wheels turn. My question is this the same symptoms your Blazer had?

It's right above the distributor, it has two hoses running into it and a 2 wire plug, ya can't miss it.









Sorry about the blurry pics, it is dark out and there was no light so I was just using the flash. HAHA!

The switch has the blue on it.

[LJP_GURU]

That’s easy access alright. Thanks for the pics as that makes it very easy to see the part on the vehicle. I will check it out and hope it is malfunctioning and that’s my fix.

[Blue Bowtie]

If that is working (you have vacuum on the upper port when in 4WD) then you might want to remove the battery and tray to look at the vacuum actuator (servo):