2003 Wrangler heat problems - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 12-06-2013, 08:55 PM   #1
Join Date: Nov 2013
Posts: 2
2003 Wrangler heat problems

I have a 2003 Jeep Wrangler 4.0L straight 6, which was experiencing heat problems this past fall/winter. We have tried almost everything, and numerous mechanics have looked at it but the problem just doesn't go away.

So far, we have:
-put in a new heater core
-new radiator and cap
-checked all blend doors (passed)
-checked all of the coolant hoses
-checked head gasket pressure (passed)
-new water pump
-replaced blower motor resistor
-replaced the thermostat 4 times

We received the jeep from a mechanic, the heat worked for a day and the 4th cylinder spark plug started fouling, so we replaced the spark plug. After we replaced that, the heat stopped working after changing the plug. The fans work on all settings, and you can get a little amount of heat on the lowest fan setting, but anything above that and it feels like the a/c is on.

We have tried almost everything we can, and any ideas or help would be appreciated. Thanks!

aabbott is offline   Quote Quick Reply
Old 12-06-2013, 09:38 PM   #2
4 Little Squirrels

WF Supporting Member
ellman605's Avatar
Join Date: Oct 2010
Location: Lewisville, TX
Posts: 718
Flushed the heater core?

'99 TJ Sport: 4.0L 12X,XXX Miles, 32RH Auto, 3.5" Suspension, 1.25"BL, SYE, D35 4.10 D30 Aussie Locked.

2013 CB500X: The toy
ellman605 is offline   Quote Quick Reply
Old 12-07-2013, 08:25 AM   #3
Join Date: Nov 2013
Posts: 2
Flushed it several times before replacing it, and flushed it after it was replaced.
aabbott is offline   Quote Quick Reply
Old 12-07-2013, 10:20 AM   #4
TJCooper's Avatar
Join Date: Apr 2011
Posts: 6
Check to make sure heater hoses are on the correct way so coolant is flowing in right direction, some heater cores have restricting valves. I don't know if jeep uses them or not, Just a thought.
TJCooper is offline   Quote Quick Reply
Old 12-07-2013, 10:37 AM   #5
Join Date: Apr 2013
Posts: 2,395
For a heater to work you need

1) good water flow
2) the water must be hot
3) good air flow via heater fan
4) air flow directed thru the heater core and no blockage of air flow thru the heater

Check each item
For first remove core outflow hose at core connection and plug it. Attach another section of heater hose to core long enough to reach radiator cap and remove cap. Hold hose over radiator cap opening and run engine and verify you have good flow. Some systems have a valve in heater lines to shut off hot water when running ac.

To check that water is hot reattach heater hose run till normal operation temp and feel outside heater hose in and out of core

For airflow just feel force of air out dash vents

Finally verify air doors in proper position to direct air flow through heater core

Also make sure ac compressor not running when just on heat( not defrost or ac) setting

If it all checks you have to have heat
Digger84 is offline   Quote Quick Reply

2003 , heat , jeep , problems , wrangler

Quick Reply

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.
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


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

» Featured Product

All times are GMT -5. The time now is 04:31 AM.

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