97 F-150 Shift Interlock and Stop Lamps Non-working
#1
10-24-2006, 03:24 PM
Join Date: Jun 2003
Location: Upstate NY
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97 F-150 Shift Interlock and Stop Lamps Non-working
My truck is currently stuck in park whenever the motor is running. However if I stop the motor and just turn the key one click I can bypass the interlock and get the transmission out of park. Also associated with this problem is the stop lamps are not working.
I have read a few threads on here which are similar to my issue, however I still have yet to resolve the problem. I have replaced the stop lamp switch on the brake pedal and the wires appear to be in good shape. This did not fix the problem. Apparently there is a short somewhere because everytime I put a 15a fuse in, it instantly blows even with the key out which tells me its either something to do with a short in the LG wire which from what I understand has constant power, or the shift interlock assembly which I have yet to dismantle the steering column. I also pulled off both rear taillights and checked under the rear end for bad wires with no luck. Anyone have any other ideas as to what area to focus on??
I have read a few threads on here which are similar to my issue, however I still have yet to resolve the problem. I have replaced the stop lamp switch on the brake pedal and the wires appear to be in good shape. This did not fix the problem. Apparently there is a short somewhere because everytime I put a 15a fuse in, it instantly blows even with the key out which tells me its either something to do with a short in the LG wire which from what I understand has constant power, or the shift interlock assembly which I have yet to dismantle the steering column. I also pulled off both rear taillights and checked under the rear end for bad wires with no luck. Anyone have any other ideas as to what area to focus on??
#2
10-25-2006, 07:55 AM
I can fix this problem in 5 minutes.
First of all, DO NOT, UNDER ANY CIRCUMSTANCES, REPLACE THAT 15A FUSE WITH A LARGER ONE. (Just had to mention it...)
Now, pop the hood and unplug the speed control deactivation switch (AKA the brake pressure switch) on the front of the master cylinder. Secure the wiring to the cruise control cable with a zip tie to keep it out of the way. Then replace the fuse. Everything should work fine again. Finally, drive up to the Ford dealership and ask them if your truck is one of the ones covered by the recall. If so, have them perform the recall on the Speed Control Deactivation Switch. If yours isn't 'officially' covered, buy the part and search on here for the instructions (I know I've posted them a few times). It takes about 10 minutes and will prevent it from happening again.
Good luck!
First of all, DO NOT, UNDER ANY CIRCUMSTANCES, REPLACE THAT 15A FUSE WITH A LARGER ONE. (Just had to mention it...)
Now, pop the hood and unplug the speed control deactivation switch (AKA the brake pressure switch) on the front of the master cylinder. Secure the wiring to the cruise control cable with a zip tie to keep it out of the way. Then replace the fuse. Everything should work fine again. Finally, drive up to the Ford dealership and ask them if your truck is one of the ones covered by the recall. If so, have them perform the recall on the Speed Control Deactivation Switch. If yours isn't 'officially' covered, buy the part and search on here for the instructions (I know I've posted them a few times). It takes about 10 minutes and will prevent it from happening again.
Good luck!
#3
10-30-2006, 02:24 PM
Join Date: Jun 2003
Location: Upstate NY
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Your a genius. That was the problem and now it is fixed thanks to the recall. There was a lot of brake fluid leaking into the plug, did the fluid come from within that bad connector or do you think it is leaking from the master cylinder itself? We'll now it's onto my next problem which I've already heard horror stories about. I just found out that I have a cracked manifold. Wish me luck and thanks again.
#4
10-30-2006, 02:49 PM
Happy to help! (Even a blind squirrel finds a nut once in a while!)
The fluid comes from the master cylinder. There is a diaphragm in there that can fatigue over time and fail. The switch was designed to withstand a high number of pressure cycles, but the little bit of vacuum that is applied to the switch can cause it to fail over time. (It wasn't designed to withstand the vacuum pulses, only the pressure pulses).
There's a pretty comprehensive write-up on the NHTSA web site. (although I can't seem to find the bookmark at the moment)
-Joe
edit: Found it!
http://199.79.180.162/prepos/files/A...5005-24323.pdf
-Joe
The fluid comes from the master cylinder. There is a diaphragm in there that can fatigue over time and fail. The switch was designed to withstand a high number of pressure cycles, but the little bit of vacuum that is applied to the switch can cause it to fail over time. (It wasn't designed to withstand the vacuum pulses, only the pressure pulses).
There's a pretty comprehensive write-up on the NHTSA web site. (although I can't seem to find the bookmark at the moment)
-Joe
edit: Found it!
http://199.79.180.162/prepos/files/A...5005-24323.pdf
-Joe
Last edited by GIJoeCam; 10-30-2006 at 03:12 PM.