This is just a quick video responding to people who have asked where to find the vacuum switch on a Chevy or GMC 4×4 vacuum engaged vehicle. The vehicle in t…
This is just a quick video responding to people who have asked where to find the vacuum switch on a Chevy or GMC 4×4 vacuum engaged vehicle. The vehicle in t…
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how much vacuum should we have on this system thanks
Great videos. Do you also have one that shows the location of the vac canister? I understand that it is a pain to get to.
My vacuum diaphram is compressed all of the way in. Even in 2wd. I unattached the vacuum hose from the compressor on the wheel well and it popped out to normal. I also pulled on the cable and that seemed to be functioning fine. Any ideas?
i have a 1997 blazer,LS that the back glass want pop open, my glass has to open befor i can get the tail gate down, i here it click but will not pop open, how can i get it open to fixs it, thanks
we have a 1996 and it is stuck in 4 wheel drive – the dashboard switch has no lights and has been replaced with a new one – still no lights – the fuse is good and we can’t find any relay in between – would you know what might be causing the problem? we cannot get it out of 4 wheel
Yes, that vacuum hose you pulled off to release the actuator. you’d need to leave that off and plug it until you can figure out why you’re getting vacuum. It could be the switch I show in this video, as this switch is what pulls vacuum from that actuator once you put it in 4wd. What that switch sticks, the vacuum constantly pulls that actuator (under the battery). It could be other things, but this is an inexpensive and common problem with these GM vehicles.
Where is the end of the actuator? Is that where the valve is? I took the valve out and it released the pressure from the vacuum but as soon as I started my truck again it sucked back in. Where is the line I should plug and what do you suggest to plug it with?
, Yes, pull the vacuum line from the end of the actuator and plug it temporarily. this should release your front differential. I would suggested investigating the vacuum switch as it’s probably stuck, allowing vacuum by.
My vacuum is stuck in. I have taken the battery and tray out and I can see that it is sucked in a stuck in 4wd. Is there a way to manually get it to release?
No, so far you’ve just tried to start the threads by hand I hope? It could be that some crud is on the threads. i would take a rage and spray something like brake cleaner on it and see if you can wipe the threads down. It’s tough because you can’t see it I know. Did it thread out easily once you got it started?
i have a 95 s10 and i took the switch out but now for some reason the new one or old one wont go back in? Did you have this problem?
Man that’s awesome! I know how bad it sucks to get stuck… but it feels pretty good to fix it without tow fees and paying someone else to do something you can do yourself. haha I’m glad it helped, thanks for taking the time to come back and post this.
It is the same and your video just helped me fix it. It was a broken vacuum hose from the actuator. Just got back from 4 hours of being stuck in the sand with no 4×4, I must have knocked loose.
Thanks again, you’re a big help.
Hi there, I just did a quick Google search and a vacuum actuator did come up as recommended parts. I assume it’s probably the same, but I can’t tell you for sure. Sorry and good luck!
Do you know if it’s the same-ish for an ’87 S10 Blazer? I’m about to check but thought I’d get your advise. Thank you for this video!
I believe it does as there are three lines. I’m not exactly sure where the third line goes, but I’ve read in the forums that it runs back up toward the fw and it should not be blocked off or the front diff will stay engaed, which makes sense. It must either feed back into the manifold or something.
Quick question do you know if it matters what line goes to what port ?
Hey guys, I have a 94 jimmy and I’ve found an electronic thing that looks like a oil pressure sensor but its not, its kinda like a vaccum switch, well sorta, the wires come from the 4WD switches and plug on this thing, then it “T’s” on to the actuator, I took it to a GMC dealership and not even they knew what the hell this thing is, but its bad and needs to be replaced, any idea?
Thanks for the video! My 01 Blazer is in 4HI and won’t come out. When I press the 2HI button, the 2 HI light blinks, I can hear something clicking near the passenger kick panel and something underneath the driver side of the truck is whizzing/clicking. The 2Hi light blinks 3 times then goes back to 4HI.
It’ll go in and out of 4HI and 4LO no problem, I’ll check under the battery tonight for the cable and diaphragm.
Blazer 99 will drive in 4 wheel but not out could it be this
That would be my guess. You could disconnect the actuator, plug the vacuum line and take her down the road.
My 4WD is trying to engage when I am not telling it to, and I am hearing a grinding sound, i know its related to the 4WD system, could this vacuum switch be leaking vacuum to the front actuator?
Hey man. I was hoping maybe you could help me out with my problem, I was driving and decided to turn around, misjudged how strong the snowbank was and it pulled me right into the ditch. I spent maybe 15 mins tryna get it out with 4×4 but it’d bring my ass end towards the ditch.I got towed out then I went to put it into gear and its like it won’t engage. It had the service 4 light on for a little while but now theres no lights on at all. It sometimes catches the into gear but then gives out. Help
Hhhmm, so I wonder if those three lines got unplugged and they’re tucked up there somewhere. They should all be together. I suppose the thing to do would be to try and trace the line from the actuator. It’s helpful to have someone move it while seaching for it.
So I am working on my mothers 2000 Jimmy, I trouble shot the valve under the battery try and found that it was not working when I pressed the button to change the gears in to 4 wheel drive. I have been trying to find the vacuum switch on the transfer case and can not locate it. All I am seeing is electrical lines and no vacuum lines…. Any advice?
Does the light blink and then go back to 2wd?
On dry pavement? Just in reverse? In 4wd right?
Ok, so it seems like you’re getting vaccum to the actuator even though you’re not supposed to. The vacuum switch on the transfer case is what sends vaccum to that actuator. Have you checked this?
When I bought the 2001 Trailblazer it was stuck in 4 wheel HI. I have the 4 button on the dash and the light is not lite up for what it is in. I put in a new switch on the dash still nothing. Checked the fuse good. Went to check the Activator under the battery. It was stuck in and took off the vac line and popped out. changed it out, but still stuck in 4 wd and no lights on dash stating that it was in 4 wheel hi. I have been watching the videos to understand what to do, but I’m still not sure.
I have a 99 S10 Blazer and I am having trouble going in reverse in 4 wheel HI range……while backing up and turning in reverse, it feels as though it is “binding up” , as soon as I straighten out the wheels it feels fine and it goes well in forward……WHATS UP ??? 25 year Navy vet. confused…..thankx
I have a S10 that will go into 4 lo but not 4 hi. I can hear it actuate but I fish tail when in 4 hi. No clunking or loud noises. Previous owner had changed the TCCM. Can you point me to any area? TIA
No problem! I hope it helps.
Thank you for making this video!!