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I have a 1999 chevy 3500 and every now and then it will not come out of park. Is there a pressure switch somewhere that might need to be replaced? and where might it be located? sometimes i can pump the brakes a couple of times and it will release the gear selector. any tips will be appreciated thanx
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It sounds like the brake transmission shift interlock is going bad. You can do an internet search on chevrolet truck BTSI. It is shown in the lower photo of the steering column this link http://www.justanswer.com/chevy/3goms-remove-btsi-solenoid-1007-silverado-2500.html It is an electric solenoid that energizes when you step on the brake pedal. It is why you need to step on the brake to shift from reverse to drive and shift out of park. The solenoid moves the rod that is sticking out of it. The rod moves and releases the column shifter so it can move from park to reverse or drive. It may be activated thru the brake lamp switch (near the brake pedal and above the steering column) -can’t remember if it has its own separate switch. Check the brake switch with an electrical meter to see if it works properly. If the Switch is OK, the solenoid is probably on it last leg. Repair it before it leaves you stranded in Park. (or by-pass it) I had this problem on my truck. Just another one of the electrical annoyances GM builds into their products. Gen3
You may have an issue with the brake on-off switch. There usually pretty cheap to replace but obviously using a good wiring diagram and a DVOM will be the best aid to diagnosing this issue. Alot of vehicles have wiring that will run through your BOO switch to the shifter solenoid to be able to release it.
I would start with a good visual inspection, also noting when the shifter will not release, having someone check the brake lights to see if they even illuminate. That there will tell you if you have an issue with your BOO switch.
Jacob, a forum member here is a GM tech so he may be able to chime in with some good service info.
Hope this helps.
GM usually has a separate stop light brake switch and a TCC/cruise control/PCM release brake switch that tells the PCM/BCM that the brakes are being applied. You probably have either a stuck TCC brake switch or it needs to be readjusted.
where would i buy one and is that what the parts people call it. (brake transmission shift interlock)
Honestly I would look to the brake light switch first and check it’s operation as it would be a much less expensive part and easier to fix in my opinion.
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