Vacuum Lines (Renix)

[NC Tom]

Folks this is an extension of my post about REM readings. I turned into a vacuum discussion, so I figured it made more sense to start a new thread.

 

I am going through my vac lines and I've been using the "MJ Projects and Write-Ups" area for guidance, BUT, it's not really working out for me. My lines aren't matching up, I'm not finding lines in question or, maybe, I just can't read the diagrams.

 

Specifically, cabin vent air/heat only comes through the defrost. @AnotherOldJeepGuy Mentioned the hard line that runs along the firewall.

SEE Engine Bay Pic.

 

 

I took another pic of a similar pic @AnotherOldJeepGuy posted about his lines. My lines appear to be different. I have 4WD he has 2WD. Does that matter for this? See Close-Up pic.

Hose "A" I found today. I cannot find where it is supposed to go. I think it's the "Yellow" hose in AnotherOldJeepGuy's pic. The "B" connection on my truck hasn't been attached to anything since I got it seven years ago. The little rubber "bulb" has a Ford logo on it.

 

Can anyone make sense of this?

[AnotherOldJeepGuy]

The rubber grommet in your circle "B" to me looks like the rubber grommet that in my picture, is actually in the hole in the firewall.  I don't know what it looks like on the other side of the firewall.

 

 

The hard plastic pipe continues from where yours stops at the washer tank, on to the connection at the airbox-to-throttle body airflow tunnel.  Note that mine used to route above the airflow tunnel, but I rerouted it under to interfere less with opening the airbox to check the filter.

 

[NC Tom]

On 5/24/2025 at 6:23 PM, AnotherOldJeepGuy said:

The rubber grommet in your circle "B" to me looks like the rubber grommet that in my picture, is actually in the hole in the firewall.  I don't know what it looks like on the other side of the firewall.

 

 

The hard plastic pipe continues from where yours stops at the washer tank, on to the connection at the airbox-to-throttle body airflow tunnel.  Note that mine used to route above the airflow tunnel, but I rerouted it under to interfere less with opening the airbox to check the filter.

 

Thanks for this.

[NC Tom]

@AnotherOldJeepGuy Do you suppose these two lines should be one?

[AnotherOldJeepGuy]

It's certainly possible that the B and A points connect, but I can't be sure from that pic alone.  I am assuming the hose that starts in circle B follows the yellow line.  If it does, and the yellow line continues over to the left edge of the engine bay and then heads down in the direction of the left side of the bumper towards a small tank (which I have heard called the football in some threads), than that becomes probably rather than just possible.  If the yellow line goes as guessed then it most likely either connects to A or to C.  I would be willing to make a guess that A is the more likely one but that is a guess.  I don't believe there is any harm trying both and see if either connection restores airflow control so the air isn't stuck only coming out of the defrost vents.  If it does then you know you have made progress and you know which connection is correct.  Of course it is also possible that the airflow control still won't work for either connection which would suggest there is a second leak, a stuck baffle, or some other gremlin, but start with trying the connections and perhaps you will get lucky and that will be the only problem with the airflow control.  Note you will need to start the engine to establish a vacuum since there is none currently, that is, you can't tell success by just switching on the system in the ACC position, since until you start the engine you won't get an initial vacuum.

 

Once you determine which connection is correct, A or C, than the one you don't connect needs to go to the heater control valve.