View Full Version : OT - no 4WD
CompositeEngr
11-26-2005, 12:31 PM
Well, the first time I tried using the 4WD this year, something is screwy.
immediately after leaving the house during the snowfall yesterday, I tried out the 4wd, and it worked. I switched back to 2wd before getting on the highway.
so I drove for about 15 miles, and went to park to get gas, and the key won't come out. So I had to go to 4 low and back to 2 hi to get the key out. Odd enough.
Now the truck won't select 4 Hi at all. It will select 4 Lo.
This is an electric shift 97 Jimmy.
Unless somebody knows an easy trick to check it out, this will be waiting for a couple of paychecks before I even think about getting it fixed.
--Mike
Toolmaker Extrodinair
11-26-2005, 02:20 PM
is it electric or vacuhm as GM used the latter on most of those. my 99 all the vacuhm hoses rotted would not shift nowhere.
CompositeEngr
11-26-2005, 03:24 PM
the hayne's manual says electric, and I looked under the truck and found the motor and leads.
The connector is secure, nothing broken.
Motor is mounted solid.
I was hoping to crawl under and knock a piece of crud out of a linkage, but its all shielded.
lugnut
11-26-2005, 04:04 PM
I had a simular problem with my GM 4X4 and it was a fuse, there is a electric heated solinoid that engages the front wheels and when the fuse blew I also lost the AC and defrosters?? Check your fuse panal.
Good luck
Mel
wierdscience
11-26-2005, 07:39 PM
Could also be one of those crappy switches GM is famous for.$20,000 truck with $.02 switches,go figure.
CompositeEngr
11-26-2005, 08:06 PM
I don't think its the switch, but I know what you mean.
When I press the 4 Hi button, 4 Hi and Low flash until I put it in drive.
Nothing happens when I press the 4 hi button if I'm not in neutral.
I checked the fuse marked 4WD today, and it was fine. I'll poke around in the other circuits tomorrow.
wierdscience
11-26-2005, 08:38 PM
Could be a loose or dirty connector in the harness underneath where it plugs in too,common source for intermitant faults.
3 Phase Lightbulb
11-26-2005, 08:44 PM
Is the 4x2 / 4x4 High / 4x4 Low all electric?
If it's manual, try shifting when in neutral and put your foot on the brake, or while moving go to neutral then switch from 4x4/4x2.
-Adrian
CompositeEngr
11-27-2005, 02:15 AM
<font face="Verdana, Arial" size="2">Originally posted by 3 Phase Lightbulb:
Is the 4x2 / 4x4 High / 4x4 Low all electric?
If it's manual, try shifting when in neutral and put your foot on the brake, or while moving go to neutral then switch from 4x4/4x2.
-Adrian</font>
Its all electric, with auto trans.
It should also shift on the fly into 4 Hi, up to a certain speed. Never tried it faster than about 15.
4 Lo seems to operate mostly normally. requires neutral and foot on the brake to engage it.
--Mike
lunkenheimer
11-28-2005, 08:05 AM
I had to work on a friend's 97 blazer with the same problem. Dealer diagnosed it as the encoder motor (on the transfer case), and wanted $250 for the part and $280 to change it.
When I went to pull it off I found that the connector wasn't screwed down all the way, and when I fixed that all was well (so far, it's been a year)
I like my 88 Ranger. All mechanical with lockers front and rear. Shoot some grease on the linkage every couple of years and it's good to go. Of course there was the minor problem of it dying in the middle of the road on the way to work this morning. It was a bad connection on the mass flow sensor. Wiggled it and vrooom. One more thing to clean up.
CompositeEngr
12-11-2005, 12:47 AM
Got the problem figured out now.
There are apparently 3 failure modes:
1. most common - switchgear fails
2. 2nd most common - motor position sensor fails
3. very uncommon - 4wd module behind the glove box fries.
Guess what I got? The module is bad. A guy at the shop put the module from his Dad's truck in mine to confirm it.
After my truck came out, GM redesigned it from a $300 black box to a $10 relay in 1998.