# 1999 gmc jimmy 4x4

**URL:** <https://community.cartalk.com/t/1999-gmc-jimmy-4x4/22241>\
**Category:** Maintenance/Repairs\
**Created:** [November 18, 2008, 5:26pm UTC](https://community.cartalk.com/t/1999-gmc-jimmy-4x4/22241 "2008-11-18T17:26:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![gmcbob](https://avatars.discourse-cdn.com/v4/letter/g/41988e/32.png) [@gmcbob](https://community.cartalk.com/u/gmcbob)\
**Post date:** [November 18, 2008, 5:26pm UTC](https://community.cartalk.com/t/1999-gmc-jimmy-4x4/22241/1 "2008-11-18T17:26:23Z")

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having trouble with the front axle disengaging also have trouble lite that says service 4wd i’ve changed fluids in the axle and transfer case.looking at a chiltons book i see this thermal actuator could that be gummed up,wore out or being that its push button control electrical? Or is there a part that normally goes bad

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**Author:** ![edb1961](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/edb1961/32/122_2.png) [@edb1961](https://community.cartalk.com/u/edb1961)\
**Post date:** [November 18, 2008, 7:32pm UTC](https://community.cartalk.com/t/1999-gmc-jimmy-4x4/22241/2 "2008-11-18T19:32:11Z")

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The transfer case on my 2000 Blazer has trouble engaging 4wd, unless I use it once a week or so. A GM tech told me that the control module (in the right kick panel) tends to freeze/lock up if not used on a regular basis. I always thought the problem was with the actuator motor on the transfer case. He recommended unplugging it to reset the module. I don’t feel like removing the panel so I just disconnect the battery to reset it. This also takes care of the 4wd Service light.

I have found it helps to be moving slowing when I switch to 4wd Hi. If all else fails I disconnect the battery. Since I’ve been making a point to switch to 4wd once a week, the truck has been behaving.

Good luck,

Ed B.

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**Author:** ![gmcbob](https://avatars.discourse-cdn.com/v4/letter/g/41988e/32.png) [@gmcbob](https://community.cartalk.com/u/gmcbob)\
**Post date:** [November 18, 2008, 10:10pm UTC](https://community.cartalk.com/t/1999-gmc-jimmy-4x4/22241/3 "2008-11-18T22:10:23Z")

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hey there i went around to a couple of shops and the gm parts man said if it was the unit on the transfer it would cost 573.00 if it was the axle servo 132.00 So i stopped at a service garage and he said ,oh yeah generally it is a electrical vaccumn unit ( i have’nt looked for it yet )but i thought he said on top of the transfer case that has a check ball in it that jams and it runs about 90.00 i’m going to look into it tomorrow,but right now the wife is going to try it since i disconnected the batt. i’ll let ya know