esof switch?/
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esof switch?/
Hey guys sorry for all the ?? my 00 v-10 has a roar in the front hub( drivers side ?) from the posts here i learned to check for vaccume leaks ..... so this morning i went out and locked the hubs in , then i started the truck . i then switched it into 4x hi and turned on the ac/ it was NOT blowing through the defroster vents on dash--- i turned the selector to 4x lo, felt it engage then i ran the vent selector to defrost and the 4x lo switch went out, or should i say the light turned off? does this point to a vaccume leak or what? it sounds like a bearing noise when driving down the road. i drove it to get a paper , when i got back i tried to duplicate the test with the hubs both locked and unlocked-- the indicator llight did not go out.. any ideas/experience with this trying to figure which direction to go in to fix. dont want to just throw money at the wrong thing. thanks-- britt
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Could be a vacuum leak. The dash switch sends a vacuum pulse to the front hubs and has the transfer case motor do its thing. The sensor for the "4x4" dash light is at the transfer case motor only. So the "4x4" dash light does not detect anything from the front hubs. So just because the "4x4" light is on it does not mean the front hubs are locked in or working.
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From: N. Georgia
Originally Posted by britt
so how to check for vaccume leaks in the system?? thanks--britt
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></o>It is easier to troubleshoot the system if you have a “Mityvac” vacuum pump. Turn the ignition switch to run (you don’t have to start the truck) and the air controls to vent and the fan control to low. If the truck’s vacuum pump comes on wait until it stops running before each test (open the hood and you’ll hear it better). First you need to remove both lines (left and right vacuum lines) from the hubs. Plug the passenger’s side line and attach the vacuum pump to the driver’s side line. Switch the dash controller to 4WD high. The vacuum gauge should go to 10 in.-Hg. or higher. (It should hold the vacuum at 10 in.-Hg. or higher for 45 seconds on engage and 15 seconds on disengage.) Repeat the test plugging the drivers side and testing the passengers side. If you have the right amount of steady vacuum the problem is probably in the hubs. If you do not have the right amount of vacuum or it is bleeding off, plug the lines back on the hubs and go to the next step. Second remove the vacuum lines from the PVH (Pulse Vacuum Hublock). This is the solenoid located on the passenger side fender well behind the battery and in front of the vacuum pump. Plug the vacuum tester into the lower hose and wait for the vacuum pump to build back up and shut off. The vacuum gauge should read and hold steady at 10 in.-Hg. or more. If it does, the vacuum reservoir should be fine and not leaking, so go on to the next step. Third, plug the bottom line back to the bottom of the solenoid and hook the vacuum gauge to the top barb of the solenoid (not the vacuum line but to the solenoid itself). Try switching between 2WD and 4WD again. The gauge should read 10 in.-Hg. for 45 seconds on engage and for 15 seconds on disengage. If it doesn’t it is probably the solenoid (PVH) on the fender that needs replacing. This was my problem so this was as far as I have gone. If all these things check out, THEN you need to go to the hubs and check them for leaks with the vacuum tester. Most of the time it’s a fuse, PVH, vacuum line or vacuum pump and not the hubs.<o
></o>Good luck, Joe
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