Help identifying hose in engine bay

[Zambeezy]

After popping the hood the other day, I noticed a hose/tube that was loose and not plugged into anything.

 

Can anyone identify this and tell me where it's supposed to go? I tried looking at some different diagrams and pictures but couldn't come up with an answer.

 

It's coming into the engine bay on the passenger side next to the windshield washer fluid tank (you can see it on the far left) and right around the oil filter area. This is a '92, if it matters.

 

[schardein]

That hose is part of your heating system.  It is supposed to attach to a heater control valve.  However, it looks like someone has removed the heater control valve from your truck and replaced the heater hoses with 1997-2001 style hoses.  In other words, they deleted it.  I've read they can be prone to cracking and leaking.  I've never had that problem, but I deleted mine anyway (on my XJ and MJ).

 

However, I also plugged the vacuum hose when I deleted the valve.  I'm not sure on what settings of the climate controls sends vacuum to that line, but you potentially have a vacuum leak there, again, depending on how you set your climate controls.  Plug that sucker.

[Minuit]

Vacuum signal for the heater control valve hose as said. Don't even think about installing one as they're very prone to cracking and leaking. Plug it if it isn't plugged off already and delete the valve if it isn't already. AFAIK the valve is activated any time the temperature slider is on the "hot" side of the scale, but don't quote me on that.

 

People might say that deleting the HCV makes the A/C less efficient (deleting the valve makes coolant always run through the heater core), but I've had it deleted for 2 years now and my A/C is nice and cold. I noticed no difference before and after.

[Zambeezy]

That hose is part of your heating system. It is supposed to attach to a heater control valve. However, it looks like someone has removed the heater control valve from your truck and replaced the heater hoses with 1997-2001 style hoses. In other words, they deleted it. I've read they can be prone to cracking and leaking. I've never had that problem, but I deleted mine anyway (on my XJ and MJ).

 

However, I also plugged the vacuum hose when I deleted the valve. I'm not sure on what settings of the climate controls sends vacuum to that line, but you potentially have a vacuum leak there, again, depending on how you set your climate controls. Plug that sucker.

Potentially really dumb question but any recommendation on how to plug it? Any one option better than another?

[schardein]

An appropriate sized screw, plastic golf tee, or steel nail trimmed so the head is flush with the fitting.  I coiled mine up and zip tied it to the wire harness above it.

[Minuit]

I just stuck a sheet metal screw in it. #8 I believe, and it's done fine with no vacuum leaks.

[ParadiseMJ]

An appropriate sized screw, plastic golf tee, or steel nail trimmed so the head is flush with the fitting.  I coiled mine up and zip tied it to the wire harness above it.

 

 

Those will work fine.  I prefer caps with a dab of glue or RTV.  Solid and cleaner looking IMHO (and not any more costly).  YMMV