Main IndexAuto Repair Home Search Posts SEARCH
POSTS
Who's Online WHO'S
ONLINE
Log in LOG
IN




95 gmc won't shift from park while running

car parts image

  Email This Post



Guest
Anonymous Poster
curtisduke@rocketmail.com

Jul 18, 2008, 5:08 PM

Post #1 of 2 (1845 views)
95 gmc won't shift from park while running Sign In

while replacing the brake booster, apparently I inadvertently disengaged a wire from the shifter lock solenoid, but cannot find the loose connection. The truck (95 gmc 2500 5.7 liter 4wd ext ext cab) will start in park, but won't shift out of park with the engine running. It must be started in neutral fore the shifter to work. Worked fine until I replaced the brake booster.


Double J
Veteran / Moderator
Double J profile image

Jul 19, 2008, 12:16 PM

Post #2 of 2 (1835 views)
Re: 95 gmc won't shift from park while running Sign In

Did you check the fuses?
Reconnect the stop lamp switch?



BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI)

CIRCUIT OPERATION
When the Brake Transmission Shift Interlock is energized. the solenoid locks the shift lever mechanism in "Park". When not energized, the BTSI solenoid returns to the unlocked position.

The components involved in the BTSI circuit are as follows:
  • BTSI Solenoid
  • Park/Neutral Position Switch
  • Stop Lamp Switch

Fuse # 16 (Turn/Back-Up) supplies B+ (12V). after the ignition switch, to the BTSI solenoid via the Park/Neutral Position switch and the Stop Lamp switch. With the key in the "RUN" or "START" position. the shifter in "Park", and the brake pedal released. the solenoid is energized. This locks the shift lever in "Park"
Note that the BTSI portion of the Stop Lamp switch (pins C & D) is CLOSED with the brakes released. Depressing the brake pedal OPENS the switch causing the solenoid to de-energize, unlocking the shift lever. The BTSI portion of the PNP switch pins B & C is closed in "Park" only. The circuit is not active with the key "OFF" to facilitate towing.

TEST.
With key in run position,shift lever in park,disconnect the BTSI solenoid connector.If shift lever unlocks,check continuity thru BTSI portion of the stop lamp switch (pins C & D) with brake pedal depressed.Continuity! replace stop lamp switch...No continuity! Locate and repair short to B+ in dark green/white wire..wire between stop lamp switch and BTSI solenoid.
Now,at first test ,if shift lever did not unlock,remove the BTSI solenoid assembly,if it unlocks ,replace the BTSI solenoid..if it doesnt,the shift lever is binding.


JIM






  Email This Post
 
 


Feed Button




Search for (options) Privacy Sitemap

web statistics