How I fixed my "Service AWD Light" problem

[biv343]

Chris Stewart suggested I post my workaround for the service AWD light issue for others to reference. While this probably isn't the best method for resolving the issue, it works, and it's inexpensive. That being said, I'll put in my disclaimer that says that "the methods described below worked for me, but I accept no responsibility for any damage that may be done to your vehicle blah blah blah...."

My 99 Bravada gave me the "Service AWD" light almost 98000 miles of relatively trouble free service. I found that yanking the fuse turned off the light and put me in 2WD mode. Kind of nice for gas mileage, kind of bad in the winter.

I purchased the parts for this at my local Pep Boys store, not because I necessarily like them, but they're close. Parts are commonly available most anyplace that sells auto parts.

Parts needed for this project:

1 - Toggle switch. Your choice. My choice was a simple black plastic toggle switch. Cost right around $4.

1 - Inline fuse holder. Little Fuse reorder number FHM-2BP. Description is "Heavu Duty Mini Fuse Inline Fuseholder". This lets you reuse the original mini fuse. Cost right around $5.

2 - Quick Disconnect Female spade lugs. Motormite PN 85452. Comes 20 to a box for around $4. Use these to connect to the back of the toggle switch.

2 - Male "mini spade lugs". Solders to the end of the wires that connect to the original fuse locations. I threw away the box, but there were a dozen in the box for about $3.

20 feet of 14 gauge wire. Color is your choice. About $4. I figured 14 gauge would be OK. It's a 20A fuse, but I doubt there is ever 20A going through that circuit. I didn't meter it to find out how much current is actually drawn.

Small rubber grommet to protect wires that pass through firewall. Had it laying around, probably $2 or so.

Heat shrink tubing, solder, other misc stuff that I already had in the garage.

Total cost is right around $20-25 depending on what you've already got laying around.

I already had the fuse removed (under hood fuse compartment, 20A fuse labelled ATC). I crimped one of the male "mini lug connectors" on one of the leads of the fuse holder, soldered and put heat shrink tubing on it. I ran the two wires to the switch through the firewall, drilling a small hole above where the throttle linkage comes through, as that seemed to be the easiest to get at from both inside and under the hood. I popped in the wire grommet and ran the wires through. I snipped the wire from one side of the fuse holder and spliced the wires leading to the switch into this wire, so the switch will complete the "hot" side of the circuit. Solder and heat shrink tubing did the trick. You'll need to solder/heat shrink one more of the "mini lugs" onto the fuse holder lead that will plug into the fuse box. Plug both of your mini lugs into the location where the ATC fuse once was, and you're almost done under the hood.

As an aside, the "hot" side of the ATC fuse connector is the one closest to the rear of the fuse box.

I removed the panel below the steering column and fished the wires through. Finding a place to mount the switch is a bit difficult as there isn't much clearance between the plastic panel and the metal of the dashboard. I got a bit creative and had to remove some of the plastic "ribbed backing material" that was on the back of the trim panel in order to make the switch sit flush. I drilled the hole, mounted the switch, crimped on the female lugs to the wires and connected them to the back of the switch. My switch ended up being about an inch down and an inch to the right of the right side of the steering column trim panel. Easy enough to get to without taking eyes off the road, and far enough out of the way that your knee shouldn't hit it.

I had thought of going to a junkyard and trying to find a 2WD/4WD switch from a late 90's blazer. That would mount right where the "Bravada" logo is on the dash. But, snow was falling and I was pressed for time.

Last step is to put the 20A fuse into the fuse holder, then dress up the wires as you see fit. With the key on, turning the switch on should result in an audible "click" from the relay under the dash, and the service AWD light will blink once. My tests seemed to show that when the switch was on, I was in AWD. With the switch off, I could do some pretty nice donuts. Kind of fun, as I have never been able to do that in this vehicle before. With the switch on, the service AWD light will come on after a couple hundred feet of forward driving. When AWD isn't needed anymore, I'll switch it off at the next stop. I'm not sure if it's permissible to switch the AWD on/off while moving, so I've been taking the cautious route and only switching on/off when stopped.

I haven't yet decided if this is my permanent fix, or if I'll do the proper repair later. I'll run with this at least until spring, as it's cold outside with about six inches of snow on the ground right now. Either way, it was a relatively cheap way to solve the problem that didn't involve getting out and plugging in a fuse when the roads got slick. I wouldn't mind that, but my wife would.

I'll attempt to post some pictures once my wife returns with the vehicle and the digital camera.

If I haven't been clear about the process, let me know and I'll try to elaborate some more.

[biv343]

Here are links to the pictures. Couldn't figure out how to add them here, so if someone who knows what they're doing would like to, it would be appreciated.

http://s49.yousendit.com/d.aspx?id=3...20ILTD0L32TI4D

http://s49.yousendit.com/d.aspx?id=3...2211OCC719IS3D

[Chris Stewart]

Thanks Biv, those are good instructions & pics and we can refer others to it.

[rlith]

I have a question...Granted, nifty idea for switching in to 2wd, but that said, why ignore the service light. You have a more advanced transfercase than the older bravadas or the 4x4's. Why ignore a potentially serious mechanical problem with a work around instead of getting it fixed properly and then using the work around for fun knowing that at any time you can simply pop back into awd? Just curious, not flaming or anything.

[biv343]

Good point rlith. In my case, it appears that the transfer case locks in AWD all the time instead of switching between 2WD and AWD like it is supposed to (with power to the ATC circuit). If the fuse is disconnected and the switch is off, it stays in 2WD.

The good thing is that AWD is only needed for about four months here, and then only a few days a week then, depending on how tempermental the lake effect snow is. My wife doesn't drive too much (maybe 150 miles a week on a busy week), so I'm not too terribly concerned with it.

That being said, I do plan on doing the "proper" repair in the future. This was a quick, cheap and dirty way to circumvent the issue until cash flows a bit more freely after the holidays.

[ericn1300]

Thanks for posting your fix Biv, seen to many threads just end with no good feed back. I wonder how much you saved? Did you get any estimates on the "proper" repair?

[biv343]

Part appears to be right around $200. I don't know what's involved with changing it, but I'd guess at least an hour or so of time, some band aids and some beer....

[YooperJ]

Originally Posted by biv343

Here are links to the pictures. Couldn't figure out how to add them here, so if someone who knows what they're doing would like to, it would be appreciated.

http://s49.yousendit.com/d.aspx?id=3...20ILTD0L32TI4D

http://s49.yousendit.com/d.aspx?id=3...2211OCC719IS3D

The picture links are no longer any good. They have been expired. Any way of sending those to me at yooperj@yooperj.com ?

[YooperJ]

Originally Posted by biv343

Here are links to the pictures. Couldn't figure out how to add them here, so if someone who knows what they're doing would like to, it would be appreciated.

http://s49.yousendit.com/d.aspx?id=3...20ILTD0L32TI4D

http://s49.yousendit.com/d.aspx?id=3...2211OCC719IS3D

Picture link is expired, send them to me and I will link them to a spot on my web page where they won't expire.
yooperj@yooperj.com

[BrownBravada]

I was just wondering my AWD works fine well now that I just changed the transfer case,but I wanted to switch mine to switch. No need for AWd only in winter and pulling my boat out of the water. Just wondering if anyone has done this too a working system also would just removing the fuse keep it in 2WD. With gas a 3.00 it might help to save some money. thanks

[Chris Stewart]

Originally Posted by BrownBravada

I was just wondering my AWD works fine well now that I just changed the transfer case,but I wanted to switch mine to switch. No need for AWd only in winter and pulling my boat out of the water. Just wondering if anyone has done this too a working system also would just removing the fuse keep it in 2WD. With gas a 3.00 it might help to save some money. thanks

I don't see a problem with it but I've PM'd Biv to see how his is doing. Maybe he'll answer soon.

[biv343]

yooperj - Sorry, my PC blew up, forgot my AF password, and I lost the pictures. I'll try to take pictures of what I did, although they aren't the greatest. Essentially, just remove the fuse labelled ATC, put in an inline fuse holder, and switch the hot side of it that feeds to the TCCM, and you're all set.

BrownBravada - if it were me, I'd probably leave it alone. In theory, as long as its 98 or newer, it should keep the AWD disengaged in "dry" weather. Only reason I switched mine was because it decided to stay in AWD all the time. Your call though - you can pull the fuse, drive around for a day and see if you notice any difference in your MPG. If it's not noticeable, I'd leave the fuse in and call it good.

So far I haven't had any problems with the "switch rig" in mine. The transfer case hasn't exploded, locked up, or otherwise fallen off like some folks thought would happen. I replaced the idler arm and LF hub bearing a few weeks ago. Other than that, it's still holding it's own. I may look into the TCCM or encoder motor now that it's warmed up, but then again, I may just leave well enough alone.

[Chris Stewart]

Thanks again Biv!!!

[chip80]

I was thinking the same thing as biv, I gained about 4 mpg while being in 2 wheel drive instead of awd. I drive about 700 miles each week for work ( about 4 months now) with no issues at all, just better mpg.

[Chris Stewart]

Thanks for sharing Chip80!!!