I drove to work this morning like normal and everything was fine. Tonight when I got ready to come home, My Tach , speed hand, the lights that indicate PRNDL are not working. I went to checking fuses and found none blown inside the cab or under the hood. The truck runs fine and all the other gauges work. Up on further looking I found that I had no power at the fuse that feeds the PRNDL fuse in the fuse box. I decided to ease on home, I then realized the truck is not shifting. I think its running in 2nd.. I drove home slow.. PLEASE tell me this is not a big deal?? I'm working 15 hours days . 7 days a week right now.. I know somebody is gonna come back with a quick fix..

 

if im not mistaken, being stuck in second is limp in mode, right? and if you're having gauge issues, sounds like a wiring issue to the icp... maybe a computer ground?

 

Gauges work fine just the speedo, Tach, indicator lights for what gear your in and it runs in second gear.... I have no idea where to start, Anyone?

 

Sounds like a bad ignition switch. If the trans defaulted to second gear starts the trans fuse is most likely not getting power as well. What year/model do you have?

 

Its a 97.... I also read about the ignition switch could be the problem. How hard a job is that with the air bag in there and all.. Is it something the shade tree mechanic in me could do?


I also read about unplugging the neutral switch and tapping it with a hammer. I just done that, I'm waiting on the electrical cleaner to dry now before going out and trying it..

 

Cleaning and tapping on the neutral switch didn't help at all... I gotta try and borrow a car from somebody to go to work now.. Y'all please think about this today and tell me something... If I could KNOW its the ignition switch, I could get it fixed but if I replace that and still have the same thing I will be out of money and so screwed.... gotta go

 

Nothing is easy to fix without seeing it. You need to diagnose the issue to make sure that is the problem. Voltage checks at the ignition switch wires and so on.

 

I got off a few minutes early today and been tinkering.. I also called a GM mechanic and that in his 37 years experience he had never seen a ignition switch cause my problems.. I'm really confused now,


any way, I went back to checking fuses in the daylight and I found I have no power in the fuse box at number 8 { CRANK} # 14 { ILLUM} and # 20 PRNDL. All 3 of these fuses are stacked on top of each other in a row inside the box. Are there anymore fusible links? Is there a relay that operates those 3 fuses? Would it help me to pull the codes? I got a friend with a scanner. The service engine soon light has been on since I bought it.. To tell you the truth I haven't seen many GMC products that the light isn't on all the time. Its raining now and that is as far as Ive gotten...Any ideas are greatly appreciated!

 

Fuse 8 has power when key is in start position.
Fuse 14 has power when headlamp switch is in park on or headlamps on.
Fuse 20 has power when key is in on, start, and run. White wire from ignition switch.
I have replaced many ignition switches for trans problems. Here is a bulletin for them as well. I would check for power on the white wire from the ignition switch.




#01-07-30-002E: MIL On, Transmission Stuck in Second or Third Gear, IPC Inoperative, DTCs P0740,P0753,P0758,P0785,P0787,P0973,P0976,P1860,P2 761,P2764 and/or P2769 Set (Verify and Repair Source of Voltage Loss - (Sep 23, 2005)

Subject: Malfunction Indicator Lamp (MIL) On, Transmission Stuck in Second or Third Gear, Instrument Cluster Inoperative (Verify and Repair Source of Voltage Loss In Transmission Solenoid Power Supply Circuit )

Models: 2006 and Prior GM Passenger Cars and Light Duty Trucks
2005-2006 HUMMER H2
2006 HUMMER H3
2005-2006 Saab 9-7X
with 4L60-E, 4L65-E, 4L80-E or 4L85-E Automatic Transmission (RPOs M30, M32, M33, MT1, MN8)

This bulletin is being revised to update model years, add additional models and add additional diagnostic information. Please discard Corporate Bulletin Number 01-07-30-002D (Section 07 -- Transmission/Transaxle).
Condition

Some customers may comment on one or more of the following conditions:
• The Malfunction Indicator Lamp (MIL) is ON.
• The transmission is defaulted to second gear (4L80/85-E).
• The transmission is defaulted to third gear (4L60/65-E).
• The instrument cluster is inoperative.

Upon investigation, one or all of the diagnostic trouble codes (DTCs) P0740, P0753, P0758, P0785, P0787, P0973, P0976, P1860, P2761, P2764 and P2769 may be set depending on the vehicle.
Cause

The most likely cause of this condition may be a loss of voltage to the transmission solenoid power supply circuit.

This condition may also be the result of an incorrect installation of an aftermarket electronic device such as a remote starter or alarm system.
Correction

Important: If the vehicle is equipped with an aftermarket electronic device and the DTCs are being set when the device is being used, verify that the appropriate fuse is being supplied battery voltage during operation. If voltage is not present at this fuse, these DTCs will be set due to lack of voltage at the solenoids. This condition is most likely to occur with an incorrectly installed remote starting system. If this is the case, refer the customer to the installer of the system for corrections. ANY REPAIRS DUE TO AFTERMARKET INSTALLATION OF ACCESSORIES IS A NON-WARRANTABLE ITEM.

1. With the ignition switch in the RUN position, test for battery voltage at the circuit fuse in the transmission solenoid power supply circuit. Refer to the appropriate SI Document for the transmission solenoid power supply circuit information.
2. If battery voltage is present at the fuse, inspect the ignition voltage circuit between the fuse and the transmission for possible opens.
3. If battery voltage is not present at the fuse, test for continuity between the fuse and the ignition switch. If NO continuity is between the fuse and the ignition switch, repair the open in that circuit.
4. If you have continuity between the fuse and the ignition switch, the most likely cause is the ignition switch. Replace the ignition switch using the appropriate Ignition Switch Replacement procedure in SI. Refer to group number 2.188 of the parts catalog for part description and usage of the ignition switch.

 

I went out to drop the steering column down to check the white wire. The truck was in a mud puddle so I was gonna move it over.. EVERYTHING works now.. I'm sure what ever it is will eventually happen again but I'm gonna leave it alone for now. Its all I can do.. LET ME ASK YOU THIS.... If and when it happens again and say I test that white wire and its dead, How come I couldn't cut it and tie into a circuit that IS hot? I priced the ignition and they wanting 150-200 bucks for it.. My funds are really reallly limited right now..