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Hi my name is XXXXX XXXXX the hood on the passenger fender well is the vacuum pump with the truck running is this pump working
Yes it is running when truck is on
I havereplaced vaccum canister and electronic dash control
do you have a hand vacuum pump
no but can get one
This must be a common problem with the 4x4
when the system defaults to defrost it mean that there is no vacuum to the control head or the control is bad but you already replaced the head. we need to find the vacuum leak. and you also can check the vacuum coming from the pump
whatshould i look for at pump to check if getting a vacuum?
hook the hand pump with a hose to the pump and start the truck we are using the hand pump as a gauge to see how much vacuum the pump is pulling it should be over 18"
Ok i will try that. what line should be used on the pump?
the line that is going to all components not the one that goes back into itself
ok i will try that. any other suggestions as i am not currently with my vehicle. If that checks out anything else?
basicly you have a vacuum leak and you are going to have to trace all vacuum lines until you find the leak. if the pump has less than 18" of vacuum it is bad. even if it runs
I can try this in the next half hour, can I stay logged on to you?
yes just respond to the post. I will be helping other people but it will notify me that you sent a message
Not aproblem pulling good vacuum
pulling good thru canister and to where line enters cab
ok ok go under the dash and find the vacuum line from out side and follow oit to the control head look for and break or split. if you do not find one remove the control head and hook the gauge to the black hose port on the vacuum harness of the controller and check for vacuum
ill check back in
I bypassed the tee and hooked up pump to ac line and ac works. what else does the vacuum pump work
that i need to check for leaks?
The tee runs to electronic relay? Is this for FWD only?
yes that is for the vacuum solenoid. right by the starter solenoid
yes. can that be bypassed temporarily? what does it operate
it operates the ft vacuum hubs it you by pass you just will not have 4x4 will not hurt anything
If leak is not in line is there anything in front hubs that can cause this. I know that FWD worked before bypass.
Thank you for your support on this and answering my ?'s
no the vacuum goes to the solenoid the to the hubs. it is unusual that the 4x4 worked and the a/c did not. hubs do not take as much vacuum to work as the a/c does. maybe the leak is small enough not to effect the 4x4.
I have to answer another person be right back.
I accept your help Thanks