YJ Heating System Explained - Page 2 - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 12-06-2010, 04:01 PM   #31
Jeeper
 
Join Date: Dec 2010
Posts: 24
I wondered why my temperature dropped and then came back up in my jeep. Thanks for the info.

Jims YJ is offline   Quote Quick Reply
Old 12-07-2010, 04:41 AM   #32
Newb
 
Join Date: Nov 2008
Location: Grand Rapids, MI
Posts: 3
recommend sticky this.

nice job.

Itzakadoozie is offline   Quote Quick Reply
Old 12-07-2010, 07:21 AM   #33
Jeeper
 
RSC17's Avatar
 
Join Date: Nov 2009
Location: Cleveland, OH
Posts: 698
Images: 1
GREAT write up. sticky.
RSC17 is offline   Quote Quick Reply
Old 12-08-2010, 06:21 PM   #34
Newb
 
Join Date: Nov 2006
Location: New Jersey
Posts: 14
Images: 4
Thanks for the great write up, maybe now I can get my heater controls together so I can finally get the dash all back together.
WranglerX3 is offline   Quote Quick Reply
Old 12-08-2010, 09:08 PM   #35
Jeeper
 
Jeep_Geek's Avatar
 
Join Date: Aug 2007
Location: Omaha NE
Posts: 380
I Never knew there was a bulb there!! Mine was the same as others have said. Very right hand side, I just pulled it out 3-4 inches and pulled the first connector on the right side and there it was!



Nice write up also! I have torn mine apart before and just sealed off the blend door to heat, i never used the power vent anyway. It stays nice and warm inside the cab.
Jeep_Geek is offline   Quote Quick Reply
Old 12-10-2010, 07:19 AM   #36
Jeeper
 
Join Date: Apr 2010
Posts: 440
I see what your talking about. I pulled mine completely out. There is actually no wiring for or with a socket for a bulb. And on my unit there is no place to actually plug a bulb socket into. I even went behind it with my pen light to shine through and the display images do not glow at all.
Dr. Venture is offline   Quote Quick Reply
Old 12-14-2010, 05:09 PM   #37
Jeeper
 
Join Date: Dec 2010
Location: Eastern Ohio
Posts: 29
Nice write up. Glad it's a sticky. My problem is, where does the wiring go in to the fan? I have a short in my heater wiring some where and I can't find the where it goes into the fan.
93 YJ Stock, 2.5 - 4 cyl, No A/C
ray1111 is offline   Quote Quick Reply
Old 03-28-2011, 02:01 AM   #38
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
In the write up you state that only the Blend gate is variable, as opposed to opperating in fixed positions (if I am understanding that correctly). But, at least in my 89, the defrost/heat lever will also partially open that gate to allow for some Defrost with some floor heat. When it goes to vent it is all vent of course.
Undead-89 is offline   Quote Quick Reply
Old 05-07-2011, 10:08 AM   #39
Jeeper
 
cd84's Avatar
 
Join Date: May 2011
Posts: 129
hi i just bought a 94 wrangler this is my first jeep and i have a few questions, i wasnt sure if this was the thread to post it on or not but there are two switches on my dash below my steering wheel, one lights up when pushed and the other doesnt, also there are two pins about a foot to the left of the switches and it looks like there were knobs on them at one point i believe there are numbers around them, i was wondering if someone could post a picture or please explain to me what they are ? thanks alot
cd84 is offline   Quote Quick Reply
Old 05-07-2011, 04:19 PM   #40
Jeeper
 
KYJeepMan1's Avatar
 
Join Date: Jan 2011
Posts: 87
Pic's Please.
__________________
2009 Wrangler X, Auto, Red, S-24 Trim
Rubicon BFG MT Takeoffs
Ace Rock Rails
Bushwacker Sill/Rocker Guards
KYJeepMan1 is offline   Quote Quick Reply
Old 05-08-2011, 08:27 PM   #41
Jeeper
 
cd84's Avatar
 
Join Date: May 2011
Posts: 129
Im not sure how to put pics on here but i think i put it on here as an attachment hopefully it works
Attached Thumbnails
Click image for larger version

Name:	IMG_0224.jpg
Views:	197
Size:	223.6 KB
ID:	48622  
cd84 is offline   Quote Quick Reply
Old 05-08-2011, 08:28 PM   #42
Jeeper
 
cd84's Avatar
 
Join Date: May 2011
Posts: 129
and i guess the pins arent as far over as i thought but theyre the ones below it thanks
cd84 is offline   Quote Quick Reply
Old 05-08-2011, 08:41 PM   #43
Jeeper
 
Xpress's Avatar
 
Join Date: Jan 2011
Location: El Cajon
Posts: 2,585
Okay, so I know my heater core has fluid circulating through it, but no matter what, I can never get the heat to come out above just warm. Do you think my blend gate could be broken, or not closing off cool air completely?
__________________


2.5L Genius of some sort.
Xpress is offline   Quote Quick Reply
Old 05-09-2011, 04:43 AM   #44
Jeeper
 
Join Date: Apr 2011
Location: Al Ain, UAE
Posts: 72
Great write up! I need help with the electrical part of this. My blower motor will not turn on, so I checked the fuses first and noticed that the fuse receptacle was melted on one side. My question; can I remove the wires from the back of the fuse box and run an inline fuse without issue? Thanks!

Bink
bink is offline   Quote Quick Reply
Old 05-09-2011, 01:23 PM   #45
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
Depending on the reason the box melted it wouldn't be a problem to run an inline fuse, It will do the same thing. you just have to get the right size fuses and wire. I would look at securely mounting whatever wire you run of course. Zip ties to the existing harness work, just allow yourself enough slack or room to get to the new fuse.

I would also label the fuse holder or nearby on the wire what the proper value is for future reference.
Undead-89 is offline   Quote Quick Reply
Old 05-09-2011, 01:32 PM   #46
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
Quote:
Okay, so I know my heater core has fluid circulating through it, but no matter what, I can never get the heat to come out above just warm. Do you think my blend gate could be broken, or not closing off cool air completely?
You should be able to move the blend gate lever on the outside of the housing with your hand. It is hooked up to a cable (like a bicycle brake cable).

When you move the housing lever, it should move your lever on the dash from hot to cool and back. If it doesn't, there is a problem with the cable. It could kinked somewhere or perhaps the cable sheath (the outer tube it slides through) is not secured at either end, the cable isn't secured tightly at either end or, rarely, the cable broke.

Also by doing this you can adjust the heat manually and see if it is the blend gate.

One other way you wouldn't get full heat, is if your thermostat is stuck open or missing. That you can verify from the dash temperature gauge.
Undead-89 is offline   Quote Quick Reply
Old 05-15-2011, 10:05 PM   #47
Jeeper
 
Xpress's Avatar
 
Join Date: Jan 2011
Location: El Cajon
Posts: 2,585
I have a thermostat for the Jeep, but didn't install it because there wasn't one in it when I flushed the system. The Dash temp gauge doesn't work either, but I know the system gets up to temp, because the radiator is plenty hot. Would installing a thermostat resolve the entire problem?

Also, the blend gate lever moves when I move the heater levers. Even moving it manually doesn't work.
__________________


2.5L Genius of some sort.
Xpress is offline   Quote Quick Reply
Old 05-16-2011, 12:38 AM   #48
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
Without the thermostat your Jeep will never get to full operating temperature especially if you are using the heater. It might be getting warm but not full operating temp.
Undead-89 is offline   Quote Quick Reply
Old 05-16-2011, 05:24 PM   #49
Jeeper
 
Xpress's Avatar
 
Join Date: Jan 2011
Location: El Cajon
Posts: 2,585
Huh, so you're saying that the thermostat opens and closes throughout the entire drive then... Never thought of it that way...

But why does this only happen on the Jeep? Doesn't happen on any of our Toyotas, all of which don't have thermostats. Is it just that efficient at cooling?
__________________


2.5L Genius of some sort.
Xpress is offline   Quote Quick Reply
Old 05-17-2011, 01:14 AM   #50
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
It depends on your engine to radiator size ratio, the amount of air flow through it, and what the manufacture decided was a good operating temp. If the radiator is big enough it is going to store and cool a bunch of coolant. when that thaermostat opens that is going to rush into the engine. cooling it down. If the coolant is cool enough still by the time it hits the thermostat again it will close until the engine heats up the coolant in it and does it again.

If the radiator is smaller, or if the outside temperature is high, or if there isn't much air flow like when in stop and go traffic or slow wheeling, the engine will heat up the coolant enough that the thermostat won't bother closing, and everything will keep circulating. Hopefully the radiator keeps up, if it can't get ahead. If it doesn't that is when you will overheat.

The Heater core is just a smaller radiator that gives off heat into the passenger compartment. Again, how cold the incoming air is how much it will reduce the temp in the heater core and how warm the air out will be. As you use the heater it will reduce the temp in the engine and will reduce how fast the engine heats up. the heater core doesn't have a thermostat to turn it off though. So without a thermostat and running the heater you may never hit full operating temp.
Undead-89 is offline   Quote Quick Reply
Old 05-17-2011, 01:18 AM   #51
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
Oh, this should happen in all vehicles. but for instance, my 87 Camaro's 305 4bbl operating temp was 220. Which as you know is higher than normal boiling. They can get away with this because the system is pressurized which allows higher temps before boiling.

The 80's Firebirds had a small spoiler underneath the car to get air into the radiator because they didn't have a front grille. Many people found out ho important that 4 inch tall piece of plastic was once they lost it and started overheating all the time.
Undead-89 is offline   Quote Quick Reply
Old 05-17-2011, 10:36 AM   #52
Jeeper
 
Xpress's Avatar
 
Join Date: Jan 2011
Location: El Cajon
Posts: 2,585
So then my Jeep must have a fairly large radiator for the small 4 cylinder, which would make sense.

But on the other hand, a buddies 2.5 jeep has no problems keeping the heat flowing through the system, it gets so hot we often have to turn the heater down/off. Which makes me think something's up. Both of the heater core lines should be hot right? Only one of them is on mine, and I know the entire system is flowing properly. Will a thermostat make THAT huge of a difference?

Also, on the heater controls vacuum lines, there are only 2 on mine. From what I've read, there should be 3, correct?
__________________


2.5L Genius of some sort.
Xpress is offline   Quote Quick Reply
Old 05-17-2011, 11:14 PM   #53
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
Yes a thermostat can make that big a difference. I would make sure your heater core isn't blocked too. Though, that is harder than just poppping in the thermostat for week, seeing what happens.
Undead-89 is offline   Quote Quick Reply
Old 05-28-2011, 07:21 PM   #54
Jeeper
 
Join Date: May 2011
Location: San Antonio
Posts: 23
Smile

Quote:
Originally Posted by cd84 View Post
Im not sure how to put pics on here but i think i put it on here as an attachment hopefully it works
Those switches are probably from some after market lighting or something like that. That's where I put my switch. Did the previous owner keep the off road lights when he/she sold it to you?

The round holes w/ numbers and the word "off" are where the controls to the A/C are supposed to be. I don't know why you don't have them since you clearly have A/C vents. Has your A/C compressor been modified for something else? i.e. an air compressor? The previous owner may have taken them off since the A/C, at that point, wouldn't be of any use.

JP_SATX is offline   Quote Quick Reply
Old 05-28-2011, 07:30 PM   #55
Jeeper
 
Undead-89's Avatar
 
Join Date: Feb 2011
Location: Loveland, CO
Posts: 760
Off topic... Just looked at that picture and noticed for the first time the ash tray, for Jeeps with AC is right in front of your knee as you drive. How the heck did they expect you to use that? I'm assuming if you are a smoker and have the AC going you are going to have the windows closed.
Undead-89 is offline   Quote Quick Reply
Old 06-25-2011, 08:28 AM   #56
voz
Jeeper
 
voz's Avatar
 
Join Date: Jun 2011
Location: Clayton, NC
Posts: 50
Most Excellent Information!
voz is offline   Quote Quick Reply
Old 09-19-2011, 08:59 PM   #57
Jeeper

WF Supporting Member
 
Join Date: Jul 2011
Location: Ft Myers Florida
Posts: 75
Images: 5
BUMP for the great info..
Walker77 is offline   Quote Quick Reply
Old 10-01-2011, 09:45 AM   #58
Jeeper
 
Join Date: May 2011
Posts: 22
Any idea on how to replace the blower motor?
wmills71 is offline   Quote Quick Reply
Old 12-06-2011, 11:35 PM   #59
Jeeper
 
Jrockstangs's Avatar
 
Join Date: Dec 2011
Location: Marseilles,il
Posts: 62
absolutely fantastic write up...helped me already
Jrockstangs is offline   Quote Quick Reply
Old 12-07-2011, 08:00 AM   #60
Jeeper
 
Join Date: Nov 2011
Posts: 717
engine temps

The engine is designed to operate with the 195 degree thermostat. You need to keep the engine temp up to get the cylinders up to temp for igniting the fuel efficiently. Otherwise you engine control will THINK it needs some choking and will enrich the fuel mix accordingly.

Using the old farmer method of heat testing. You should be able to hold the top radiator hose lightly in your hand without burning, not really comfortable but you can do it. If you can hold it tightly, it isn't getting up to temperature. Same with heater. You shouldn't be able to hold the supply hose to the heater tightly. You should be able to hold the return hose fairly tight. BUT if it isn't uncomfortable, you aren't getting enough flow through the core.

This can be from a hose problem or from a blocked core. Another thing people don't think about is that the thermostat isn't an open/shut switch. It modulates. It also presents a restriction when totally open. The design is that when it is totally open, with that amount of restriction, there is still enough flow for the radiator to cool the engine under 120 degree ambient.

Now, if you remove the thermostat, you are removing that restriction. When the water pump forces water into the engine, it is looking for the path of least resistance to return. The radiator core, with no thermostat restriction, provided a much easier path and this reduces the flow through the more restrictive heater core.

When the engine is running at normal, or slightly below normal, temperature the thermostat provides quite a bit of restriction, thereby forcing more coolant through the heater core. Faster coolant flow means higher operating temperature of the heater core. Higher delta T across the heater core means more heat transfered to the air coming in and more heat in the cab.

ballistx is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Oil Furnace - Hot Water Heating - Aquastat Settings TJeepman Off-Topic 1 10-07-2010 06:27 PM
Jeep Air System Gavin19_76 YJ General Discussion Forum 6 05-17-2010 12:45 PM
anyone have an AEM Brute Force air intake system installed? BlueStar TJ General Discussion Forum 25 04-16-2010 07:55 PM
Info on a Hydrogen System (with pictures) simpsonsdotcom TJ General Discussion Forum 3 04-03-2009 08:46 PM
Our Tax System Explained In Simple Terms stainless Off-Topic 15 05-03-2007 09:15 AM


logo carid shop wrangler parts carid fender flares custom wheels store avs deflectors at carid

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 02:39 PM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC