Hear 4x4 click but won't engage 98 Blazer
#11
12-21-2013, 05:17 PM
1. Vacuum reservior is in the driver front fender, between the ABS unit and the firewall. Black plastic, and the nipple for the vacuum line is (barely) visible.
2. TCCM is behind the passenger side kick panel.
3. It will dribble out of the lines when you remove the connector from the vacuum switch on the transfer case.
4.5 Without vacuum from the vacuum switch, the actuator will not move.
5. Good indication of no vacuum available to either 4WD or HVAC systems.
6. No problem ,that's why we're here
Read post #2 again, second paragraph. A lack of vacuum would explain both of your HVAC and 4WD issues. Let us know what you find.
2. TCCM is behind the passenger side kick panel.
3. It will dribble out of the lines when you remove the connector from the vacuum switch on the transfer case.
4.5 Without vacuum from the vacuum switch, the actuator will not move.
5. Good indication of no vacuum available to either 4WD or HVAC systems.
6. No problem ,that's why we're here
Read post #2 again, second paragraph. A lack of vacuum would explain both of your HVAC and 4WD issues. Let us know what you find.
Last edited by Captain Hook; 12-21-2013 at 05:21 PM.
#12
12-22-2013, 11:12 AM
If you have no movement in your vent controls then you have a vacuum leak as that also controls your HVACX as well as the 4x4 system.
The vacuum canister is in the wing and the TCCM in behind the passengers foot well.
The vacuum canister is in the wing and the TCCM in behind the passengers foot well.
#13
12-24-2013, 11:17 PM
Hello I had the same problem on my 98 Blazer. I had to replace the switch on the transfer case because the front was trying to engage while it was suppose to be in 2wd. after I replaced that the vents would only blow out the top and then the 4x4 would not work at all. So I figured that I had broke a vacuum line. I took out the battery and disengaged the vacuum actuator from the front axle cable was able to pull it up and set it on the top of the radiator and then put the battery tray and battery back in so I could start the truck and switch from 4wd to 2wd and watch at the same time. After all that it was the vac hose the ran from the t fitting by the ABS down behind the motor to the switch on the transfer case. replaced it and both problems solved the vents change from top to bottom and 4x4 works again
#14
12-25-2013, 04:09 AM
What size hose is that T fitting and does it lead to the 3 port vacuum fitting? If so which fitting? I looked at the T fitting you speak of. I replaced the line that goes to the HVAC under by the throttle body (7/32).. And the hose that leads to the fender wall (5/32).. The other fitting has a (5/32) hose and it is only 5" long. I capped with screw now the vent controls work but not 4x4
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