Vacuum lines in engine bay

TJartist · Nov 15, 2021

as previously posted I am having trouble with no hot air out defrost vents. others suggested looking for vacuum hose leaks in the engine compartment for starters. I am currently doing that but is is very cold out here and if it is cheaper and faster to just replace the whole assembly in engine bay I would rather do that. On youtube it showed several links of people doing that and said complete assembly cost $15. The problem is that all my searching turns up those same assemblies but the are not for 1997 TJ. Does anyone know a link for the 97? most of my searches for vacuum lines ends with engine vacuum lines not Hvac. I just don't seem to know the correct names to get anything to come up. I will also check my vacuum control valves near the gas peddle to see if the door actuator is broken. but as always I would like to have some parts in hand before I start as it is just too cold outside to work for very long. thanks

PirataCoqui · Nov 15, 2021

Your best start for really getting to know what your vacuum system is SUPPOSED to be is to look for your evap sticker under your hood.

As far as the whole assembly is, pretty sure for $15 they are referring to all the tubing. If you don't have an EVAP code, IE check engine light, the lines in question are likely plugged.

If you don't have a check engine light, I would recommend against opening a can of worms by blindly replacing EVAP related parts unless you have reason to believe you need to.

From what I have read during my research hunting down other problems in my TJ, the line you are looking for might be the line running from the driver's side of the TJ (originating on the intake manifold) towards the firewall and then over towards the battery before splitting, with one line going into the firewall and the other under the battery tray.

Trace that vacuum line and you will likely find the culprit, assuming your issue is vacuum line related.

TJartist · Nov 15, 2021

Ok I have been listening to all what everyone has been saying and watching youtube videos to trace down the lack of heat at the defroster window vents. First it looks like all my vacuum lines were ok and when I was under the dash and slide the heat control levers all solenoids moved the control arms. so all looked good, except the top one seemed like it flopped around a little and from watching videos was a symptom of a broken gear/shaft. I disconnected it from the solenoid metal arm and tried to pull the plastic gear out by inserting a screw into the plastic hole on the back of the gear. at first I could not pull it out, but then I decided to go for it and pull as hard as I could and I finally got it out. and yes it was broken, where the plastic gear is molded to the shaft as it then goes to the bent arm which is connected to the solenoid by a metal clip. so I ordered both upper and lower plastic control arms. one is in stock the one I need is out. My questions is: I did pull the gear out as well as its little tail. However looking at the pictures there seems to be a little tab/nipple at the end of the tail. this did not come out with the gear and tail. So hopefully it may have fallen out as I pulled it out or am I screwed in that it may still be lodged in there and will prevent me from pushing the new one in to click into place. Its really tight under there and I am basically reaching from underneath to get it, while shinning a light through the lower part of the steering wheel lower cover which I removed. any thoughts?

NOLAJeep · Nov 15, 2021

My a/c heat was stuck on defrost. Had a small leak at the T where the zip ties are in the picture. My 2 cents.

PirataCoqui · Nov 16, 2021

TJartist said:
Ok I have been listening to all what everyone has been saying and watching youtube videos to trace down the lack of heat at the defroster window vents. First it looks like all my vacuum lines were ok and when I was under the dash and slide the heat control levers all solenoids moved the control arms. so all looked good, except the top one seemed like it flopped around a little and from watching videos was a symptom of a broken gear/shaft. I disconnected it from the solenoid metal arm and tried to pull the plastic gear out by inserting a screw into the plastic hole on the back of the gear. at first I could not pull it out, but then I decided to go for it and pull as hard as I could and I finally got it out. and yes it was broken, where the plastic gear is molded to the shaft as it then goes to the bent arm which is connected to the solenoid by a metal clip. so I ordered both upper and lower plastic control arms. one is in stock the one I need is out. My questions is: I did pull the gear out as well as its little tail. However looking at the pictures there seems to be a little tab/nipple at the end of the tail. this did not come out with the gear and tail. So hopefully it may have fallen out as I pulled it out or am I screwed in that it may still be lodged in there and will prevent me from pushing the new one in to click into place. Its really tight under there and I am basically reaching from underneath to get it, while shinning a light through the lower part of the steering wheel lower cover which I removed. any thoughts?

A picture of what you removed and of what you ordered would help. If you could get your phone in there to snap a picture/video of what was left behind, it should give you the answer you are looking for.

Another option is If you had a snake inspection camera, that would also get you visibility into tight spaces.

TJartist · Nov 16, 2021

this is what i pulled out. Mine was busted where flutted gear goes into arm shaft. pretty much like all others I saw in the youtube videos. what I had to do was to pull the gear out of inside the blend door. since it is broken off inside you can not get it out. So I used a dry wall screw and turned it into the hole in the center of the plastic gear, and tried to pull. But it would not come out. so I pulled really hard and it finally came out. what broke on the end of the gear part is the little knob which holds the assembly in the blend door. I actually semi glued mined back together along with a screw between the two pieces if I need to use as an emergency. I have ordered one but all suppliers I checked were out of stock so who knows if and when I may receive it.
this is the piece: https://www.quadratec.com/p/omix-ada/upper-heater-blend-door-lever-wrangler-tj-17910.02

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Vacuum lines in engine bay

TJartist

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PirataCoqui

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TJartist

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NOLAJeep

...hold my beer.

PirataCoqui

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