I Need Help With A Short....

[StormRider]

I got a 97 GMC Yukon 4x4. I went 4 wheeling the other day but when I went to switch it back to 2 Hi, it blew a fuse. Everytime I put in a fuse and hit the 2 Hi button it blows the fuse. I know there is a short somewhere but where? Where do I start looking? Does anyone have a wiring diagram or know what I should do? Thanks in advance.

Storm.

[DirtyLarry]

Well, first off….next time you buy a vehicle do yourself a favor and try to steer clear of any 4x4 an electric shift transfercase, as they are junk and not reliable although manual shifts are getting harder and harder to find every year. I have a ’04 Hoe with buttons and I hate it.

In order to see what is really going on you need to put a scan tool on it to narrow down the circuit where the problem is. I would suspect you will find a C03** code. To take a stab at it without a scan tool, I would say you could have a short but most likely a stuck encoder motor. The encoder motor is mounted on the tranfercase and does the shifting that a manual floor mounted lever used to do flawlessly. You might try tapping on the motor (like the ole starter motor truck) while someone pushes the button to see if that will allow it to shift. Just like a starter motor sometimes whacking it will allow it to work one more time and other times it won’t do anything.

These electric shift pieces have a few electric gizmos that haven’t earned themselves points in the reliability department…….Control head (in dash buttons), Tranfercase Control Module (TCCM), Encoder motor, front axle disconnect and all the wiring that supports the system.

I used to work on GM TAC line in Detroit and we used to get these calls all the time from dealers. The biggest problem with the encoder motor is it is mounted under the vehicle on the tranfercase where it is susceptible to roadsalt, dirt, etc. Plus the motor doesn’t get used all that much compared to a starter motor.

You could always swap in a manual shift NP241 and fix it for good.