I can shift without pressing the brake and no cruise.

[thegawd]

1997 k1500 5.7 Burb.

this has been going on since I replaced the brake booster in the middle of the summer. I have replaced the brake switch and it didnt change a damn thing. that was so frustrating that I wanted to smash things, but I took a break instead.... half a yearish long break. LOL. I need to make this work right so I can feel safe letting my daughter, a new driver, drive it. I have been dreading climbing back under but I keep putting it off and I need it fixed.

it has to be the wiring right? that's guna suck to deal with under there I could really use some insight to this problem and it would be nice to get my cruise control back.

plus I need to give this long/bent specialized needle nose pliers back to there owner... LOL

I had a small plastic part fall on my face and couldn't figure out where it came from. something from the shift interlock system? I dont know. I'll get a pic in a bit.

edit... oh I just remembered I started a thread on tis before but no one responded.... pic

Thanks

Al

 

[Eveready]

Not sure what you mean about shifting without pressing the brake? Are you saying that it falls out of overdrive lock at random? You changed the brake switch and it still does it, correct?

One test is to use a small bungee cord to hold the pedal in the up position and drive it a little and see if behaves the same way. This eliminates vibration or an accidental pedal touch as the cause. Don't leave it on there though, especially with a new driver as you will need heavier brake pressure while the bungee cord is in place.

I had this problem with an old van and it turned out to be the pedal spring being weak, causing the pedal to vibrate just enough to make it jump out of lock. The switch itself was not bad. I drove it for a while with the bungee in place and it "fixed" the problem but it was unsafe because of needing extra pedal pressure so I emphasize that this is only a test.

I would appreciate it if @evilunclegrimace or @someotherguy or @HotWheelsBurban would jump in here as all have much more experience with these trucks than I do. My experience with a similar problem was with a different species of vehicle. Good luck !

 

[stutaeng]

Yeah, shift interlock solenoid. I was messing with my 00 K3500 trying to figure out why I didn't have brake lights. Taking things apart trying to change the brake light switch I couldn't get the lever into the P position. I disconnected the shift interlock solenoid and that did it. Not sure what happened, but just left it like that. Eventually changed the multi-position lever, since the brake light switch didn't work. I eventually fixed the issue. It had some hacked wires in the fuse box, but I suspected one of those 2 things were bad. I can't remember if my cruise control worked before, but it does work now.

Then a few months ago on my 99 I went to get lunch and the damn lever wouldn't go into Park! I had to shut the engine off in N and leave the keys in. When I got home I tore it apart and that shift interlock solenoid had popped off. I again took it off, LOL.

But yeah, if you remove that thing, you can shift without pressing the brakes...like the old cars from the 70s or whatever.

Did you drop the column when you changed the brake light switch?

Not sure what that plastic thing you posted is.

 

[stutaeng]

Here's what it looks like:
https://shop.advanceautoparts.com/p...ymme&vehicleIdSearch=33172&isAllVehicle=false

On your shift lever you have two little ball joints. One side goes to your tranny and the other get this little guy. Based on your brake light switch signal, it will allow the shift lever to shift or not. Looks like an electromagnetic switch, similar to those security doors that have like a magnet switch and when enabled it will activate and you can't open the door..

 

[thegawd]

thanks guys I'm just running out the door but for clarification I dont need to press the brakes to move the shifter to move out of park....

 

[thegawd]

you know, I could have 2 different problems.

so, I just got back, tried pulling up on the break peddle to see if cc would engage and nope... that was a great idea though. thanks!

i have other work to get to today but I might take a look at this later on today if it dosent rain. for F Sakes! get on with this so called polar vortex. LOL. I need frozen mud! Lol.

Al

 

[HotWheelsBurban]

Not sure what you mean about shifting without pressing the brake? Are you saying that it falls out of overdrive lock at random? You changed the brake switch and it still does it, correct?

One test is to use a small bungee cord to hold the pedal in the up position and drive it a little and see if behaves the same way. This eliminates vibration or an accidental pedal touch as the cause. Don't leave it on there though, especially with a new driver as you will need heavier brake pressure while the bungee cord is in place.

I had this problem with an old van and it turned out to be the pedal spring being weak, causing the pedal to vibrate just enough to make it jump out of lock. The switch itself was not bad. I drove it for a while with the bungee in place and it "fixed" the problem but it was unsafe because of needing extra pedal pressure so I emphasize that this is only a test.

I would appreciate it if @evilunclegrimace or @someotherguy or @HotWheelsBurban would jump in here as all have much more experience with these trucks than I do. My experience with a similar problem was with a different species of vehicle. Good luck !

Appreciate the vote of confidence, but this is not a problem I have run into yet! Sounds like something in the linkage is out of whack, or a solenoid as was suggested.

 

[Eveready]

Appreciate the vote of confidence, but this is not a problem I have run into yet! Sounds like something in the linkage is out of whack, or a solenoid as was suggested.

You have been around so many of them I figure you might have seen it . The solenoid does sound like a suspect for sure.