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96 Tahoe blows 4x4 fuse - suggestions?


Adventurer_96
12-14-2008, 02:56 PM
I just got back from driving in a snowstorm which is the perfect time for your 4x4 not to engage.

I read through this thread:
http://www.automotiveforums.com/vbulletin/showthread.php?t=879194&highlight=transmission+fuse

and this:
http://www.automotiveforums.com/vbulletin/showthread.php?t=931503&highlight=actuator

but I wanted to ask more specific questions.

1996 Tahoe, 5.7, electronic 4x4 control. Press 4HI and the light flashes, you can hear a small "clunk" but the light continues to flash. 4LO gives a bigger clunk, but 4LO flashes with 4HI on for a few seconds, then back to 4HI flashing.

The 25 amp fuse for the 4x4 inside the door blew, so I replaced it with another fuse and it blew as well when I turned the key on (without starting) and pushed the 4HI button while in Park.

Sounds to me like the switch is probably good but there's a short somewhere in the wiring, probably a bad actuator?

If it is, I'm guessing I'd test it by unplugging the actuator, replacing the fuse, and checking for 12v at the wires? How hard is it to splice in the new style actuator? Not looking forward to that...

BTW, transfer case fluid changed six months ago, and worked fine the couple of times I selected it previously. Transmission fluid was changed in August, filter replaced.

Thanks...


ETA: FIXED, thanks to the help here!

MT-2500
12-14-2008, 05:20 PM
The actuator just plugs in.
To change just un scew it out of axe and screw another one in.

To test look wiring and plugin over.
Unplug it and switch 4W in and out and see if it still blows fuse.
If not to test actuator.
If the two wire old style actuator take a fused jumper and hook up acuactor to it and see if it blows fused jumper.

The actuator is a reverse ground and hot side kike a window motor to get in to push in and out.

Parts places usually have new ones for less than a 100$ USA.
Good Luck

Adventurer_96
12-14-2008, 07:46 PM
The actuator just plugs in.
To change just un scew it out of axe and screw another one in.

To test look wiring and plugin over.
Unplug it and switch 4W in and out and see if it still blows fuse.
If not to test actuator.
If the two wire old style actuator take a fused jumper and hook up acuactor to it and see if it blows fused jumper.

The actuator is a reverse ground and hot side kike a window motor to get in to push in and out.

Parts places usually have new ones for less than a 100$ USA.
Good Luck

I'm guessing I've got the old temp-kind, is it worth updating or just saving the $$$ and installing the old kind? I'm worried about the hassle of re-wiring and upgrading.

Adventurer_96
12-16-2008, 10:47 AM
I'll be out of town for a couple of days, but when I get back I'll try to swap out the actuator.

I'll just go with the older kind rather than spend extra money and time on an upgrade.

My Haynes manual is strangely silent about the actuator. Where does it live exactly?

MT-2500
12-16-2008, 11:54 AM
I'll be out of town for a couple of days, but when I get back I'll try to swap out the actuator.

I'll just go with the older kind rather than spend extra money and time on an upgrade.

My Haynes manual is strangely silent about the actuator. Where does it live exactly?


You will find it on right side axel housing in front.
Good Luck

Adventurer_96
12-21-2008, 12:02 AM
Thanks, I'll pick up an original style replacement and try to replace it. I'll post back results, hopefully someone can learn from this as well.

MT-2500
12-21-2008, 09:29 AM
You are welcome.
GOOD LUCK

Adventurer_96
12-22-2008, 11:30 PM
Thanks again for all the words. Honestly, the hardest part of the job was deciding if I wanted to go through the trouble of upgrading to the new actuator, and finding the original-type part at the local shop. They're all sold out, imagine that after the weather we've been having.

I chose to keep the older style part because it's cheaper, bottom line. My 2001 Yukon is the nice truck I'll keep forever, and while I hope to drive the Tahoe for a long time I couldn't see spending an extra $75+ on it, plus the extra time under the truck in a freezing cold garage.

Very simple replacement. Unplug the two-prong connector.

Slide the wiring harness from the actuator off the flat spring-steel mount which is riveted to the axle housing.

Unscrew the actuator with an open-end wrench or locking pliers.

Replacement is the opposite. A whopping 10 minutes under the truck, and a quick test drive around the block proved it's back up and working.

Thanks again for the words, this was a very doable fix for anybody. I didn't even need to jack up the truck!

MT-2500
12-23-2008, 11:09 AM
You are welcome and thanks for posting back how it went.
Glad you got it fixed.

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