This video overviews easy ways on how to troubleshoot 4x4 4wd issues with Chevrolet S10 or GMC Sonoma. This also works for the blazer and jimmy in similar year models (94-2005) Contact me at dpturner486@gmail.com
There are 3 vacuum lines on the switch in the transfer case. 1 is vacuum source from the line at the drivers fender coming off the check valve T. 2nd one is going to the vacuum solenoid under the battery that locks the front end in. 3rd is a vent that runs to a Y. There is a vent on the top side of the transfer case to the y then goes up to the transmission dip stick and is zip tied there. Also the supply vacuum hose comes off the drivers side manifold over to the check valve T. The Check valve T feeds a line to the Heater controls and also plugs into the vacuum accumulator. The nipple for the accumulator is under the ABS pump on the fender well. Vacuum line sizes are 5/32” and 7/32”. Also 3- 2” pieces of 3/8” are needed. Check to make sure the cable under the battery on the vacuum solenoid is free by squeezing the solenoid. Also using a brake bleed pump pull a accumulator on the solenoid to check for its operation. The failed switch on the transfer case allows tranny fluid into the lines and solenoid swelling and rotting the rubber. If your getting tranny fluid into and out of the vent line the the output shaft seal is bad on the transmission allowing tranny fluid into the transfer case. This overfills the transfer case pushing it out the vent and into,all the vacuum lines and heater control. Eventually this will rot all the rubber. Hope this helps…..
Just wanna say one more time thank you. You saved me a lot of money and a headache gone. It was the diaphragm under the battery. Slight tear. And to the 25 people that disliked this, enjoy paying the local mechanic bill
I checked the fuse , then the push button for activation, then removed the battery box so I could take a look. Started tracing the vacuum line and found it cracked and detached where it connects to the nipple on the driver side fender well. I replaced the 5/32 hose and it seems to have solved the problem. Now with a basic understanding of 4x4 I can fix my problems and save big bucks. This was by far the best video that I reviewed, Thanks !!!
Kevin C I had a 1991 Jimmy that used this same vacuum actuator switch. I replace 3 in 5 years and it always failed in deep snow towing the snowmobiles, very frustrating. The dealer did two under warranty and we did the third one on my friends hoist and said we need to find why these are getting all gummed up and the ball was ceasing. We traced the hoses on the top of the switch and found one line was a breather vent that ended behind the grill, in front of the battery with a foam filter on the end so this was intended to allow clean air in the tube. A closer look we found whoever installed the battery tray at the factory had pinched the hose and put a big slice in the hose which allowed it to suck in dirt. we cut the hose before the slice and stuck the filter on the end. No problems for the remaining 15 years I owned the vehicle.
I just fixed my 4x4 not engaging. I got a clue when my HVAC would not switch from top to bottom vent, that's a vacuum leak. Sure enough opened the hood and could hear vacuum hiss. Main hose coming off the manifold under the throtle body was almost completely broken. I shortened the hose 1" and connected it. No hiss, HVAC and 4X4 all work.
@@DustinT I have the same rotted line where you applied duct tape on... Do you know what size is that specific line if I have to replace it...... Edit: Never mind I fixed it.... I cut the rotted pipe line on both side... It was 7/32 cable.... used connector on both ends and fixed it under 10$
Having problem finding vacuum diagram for my '2000 ZR2. Got any links? Truck is new to me. Need diagram of hookups on driver's side. Got some loose lines I need to find connections to. Any help would be appreciated, thanx!
To fix your fuse issue get a aftermarket wiring harness to plug in to your oem harness the aftermarket harness should have the same colorcode to your radio. You have a wire crossed and it is most likely the green wire crossed.
Get your actuator from O’Reillys or your reputable parts house that has a Lifetime Warranty. I’ve gone through 2 in the past 4 months. That actuator tears extremely easily. Especially down here S. of Houston where it’s hot as hell. My main vacuum line to the actuator was just falling off also. Use a tie rap to hold it securely to the actuator
Currently, it is in 4 low /4 high but I cannot get it to ship the 2 Wheel Dr. I bought a new vacuum switch unscrewed the old one but now I cannot get the screw in. It is the wrong size or something. but that is not possible because it just came out of those threads. With it being in four-wheel-drive, that would mean the button would be pressed if it was screwed in and I can feel my finger in feel the part that pushes in the button, but I do not think it is put pressure on it. it still does not screw in. I’ve tried pressing the button while someone starts it and tries to shift it into 2 Wheel Dr. But it’s still will not shift into 2 Wheel Dr. any ideas?
did you get a fix for the dead battery issue. We had same issue with my sons S10. It was a unique power line for keeping the radio on after the car was off and before opening the door. It was a a high amperage fuse under the hood. The new radio we installed did not utilize that feature. Pulled the fuse and we no longer had dead batteries. If you need more info let me know.
So it is not ice freezing the actuators. What happens is the input shaft seal in the transfercase is bad allowing trans fluid to transfer from the transmission to the transfercase. When the transfercase fills high enough transmission fluid get in your vacuum system via the vacuum switch which starts degrading the rubber in your actuators and vacuum lines. This will also cause problems with the hvac vent controls eventually.
The front differential on my 2003 GMC Sonoma is locked in 2wd. The shaft that is connected to the actuator cable can't be pulled out, even manually. All other parts have been replaced, actuator, actuator switch, vacuum lines. As said above, even with the cable disconnected the shaft cannot be manually engaged
So my switch works just like yours I hear the noises like it locks in but still no 4x4. It acts like its locked in and the buttons say it is in 4 wheel drive but it isnt. when I press the 4low button my gear ratio does change but still no power to the front wheels. Could my problem be the boot under the battery?
xyzz Z I would start by removing the upper plug on the transfer case. Does transmission fluid come pouring out? If so the seal between the transfer case and transmission is leaking. Replace the $20.00 seal and blow out all vacuum hoses with trans fluid in them. This is very common on second generation S-10’s, Blazers and GMC and Oldsmobile “clones.” Then I’d go to the actuator under the battery and battery tray and look for diaphragm tears, a rusted/frayed cable and disconnect the hose to the actuator and look for transmission fluid. Spray the cable with a good corrosion inhibiter, as long as you are there. Finally trace all vacuum lines and replace any and all leaking vacuum lines. If that fails, it might be your switch in the dash.
John Belliel I would be tempted to replace the 4WD switch initially. It’s only $20.00 at NAPA and could be your problem. Obviously you are overloading the circuit that is blowing the fuse. However, where that overload is located is an entirely larger issue.
On my 03 S-10 the 4WD wasn't working because the vacuum line that engages the actuator under the battery was rotted. The vacuum line runs from that transfer case switch that Justin showed us up over the top of the passenger side of the engine to under the battery where the actuator is. (BTW, do not buy the Dorman actuator if yours goes bad, they are cheap junk). I bought a new length of hose to replace it and ran it so it wasn't laying on top of the valve cover for that is where it rotted due to the heat. Any parts store has the hose in bulk. Just buy the length you want. A second line that comes off that transfer case switch is what makes the actuators under the dash that controls where the air is directed in the cab. So if when you turn the direction of where the fan blows(feet, face, etc) and it doesn't change, it is because either that hose is rotten or the transfer case switch has gone bad allowing transmission fluid into the lines. This can be a big problem as it could be damaging those actuators under the dash and they are a pain to change as you have to take the dash out to get to them. It could also damage, as it did mine, the temp, fan speed, direction of air flow switch in the dash. That's not so hard to replace. There is also a round vacuum collection ball in the drivers side fender that will get tranny fluid in it. Hope my experiences help someone.
One hose is: (1) Vent to Atmosphere; (2) Source of Vacuum; (3) Actuator. If you place the Index Pin at 12 o’clock and go clockwise then: Vacuum Supply/Source; Actuator; and, Vent to Outside. It doesn’t really matter, it only matters that the hoses have integrity and are not leaking (or have transmission fluid in them)! The cap ensures that the hoses are oriented correctly. At 6:28, that line/hose should plug into your vacuum reservoir (not ABS) which is hidden in the driver’s side fender. Sometimes that nipple is broken and the hose is disconnected.
i got stuck when my s10 was supposed to be in 4wd and the front tires wouldnt pull, i kept spinning and fire started dripping from somewhere under the front. what could have caught fire?
Ky Miles sadly yeah it had fire dripping from under it. idk what burned up i thought maybe it wasnt fully engaged and the gear burnt off but idk because it was dripping like plastic
Ky Miles I looked under it to see because i seen a little smoke but i dont think anything metal could have got that hot to melt like that and drip just from the 4wd but im not sure
Do not buy the doorman replacement actuator I had to warranty that dang thing out 6 times I went to the junk yard and got a factory gm one and it's been good for over a year doorman is the only manufacturer that makes a replacement actuator and they just don't make the diafram rubber as good as factory rubber please trust me on this. Go to the salvage yard!!!! ZR2s Rock!!!!!!
Someone PLEASE help me!! My 99 Blazer has all of the 4x4 lights on and when I press a button it wont do a single thing... not too sure what the deal is someone please help!!
+Jason's Journeys - It might be your Transmission Fluid Flooding. Why? There is a Rubber O Ring between your Transfer Case and Transmission.... When that goes bad.... It leaks into the Transfer Case... When the Transfer Case is full..... The Vacuum " SUCKED " that into the Vacuum Line. By doing that, the Line got Flooded and Vacuum Loss causes NOT to be working correctly! NOTE 1: TO FIX:.... Under the Hood.... Find the Vacuum Line that is in the " Middle " of the Engine, close to your Wiper.... That is the Line.... Take that off... Then take the Line that is " Under / Close " to your Transfer Case Off.... IF YOU SEE DRIPPINGS..... You have a Leak.... Go back to under the Hood... Take that Line and BLOW on it..... You should see bunch of Fluid coming out..... That means you are freeing the Vacuum Tube from Transmission Fluid. NOTE 2: REMEDY.... If you have Trans Fluid Leaks... Try a Bottle of Lucas Transmission Sealer..... This will help you for a while. :)))))))))))))
