Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Green Jeep on November 29, 2010, 07:37:40 PM

Title: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Green Jeep on November 29, 2010, 07:37:40 PM
Is there a valve that fails or something?

Thanks in advance Maf
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Dutch on November 29, 2010, 07:40:41 PM
Blend doors mechanism is fooked.

Search Blend door on the forum for causes & fixes.

1=dash out, the other 2, is going in through the side with an ebay fix.

This fault is so common on Grand Cherokees even videos are shown on you tube how to conduct this repair. To get this repaired at your dealer with dash removal without this kit will cost approximatelly £800.00-£1,000.00.

If your Jeep Grand Cherokee heater only blows cold on one side all of a sudden, or seemed to just quit producing heat one day - you most likely
suffer from blend door failure.

Blend doors are small airway control doors that move into positions to blend hot and cold air to your liking based on where you have the temperature setting knobs positioned. These little plastic flap doors hide behind your glove box in your A/C system's housing, and move up and down to pass heat or cold air as you command.The material has caused them to be weak and brittle allowing them to fall apart thus only allowing cold air through the vents


 http://shop.ebay.co.uk/?_from=R40&_trksid=p3984.m570.l1313&_nkw=grand+cherokee+blend+door&_sacat=See-All-Categories (http://shop.ebay.co.uk/?_from=R40&_trksid=p3984.m570.l1313&_nkw=grand+cherokee+blend+door&_sacat=See-All-Categories)
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Mike Pavelin on November 29, 2010, 07:51:47 PM
Mansfield 4x4 do a kit. About £100.
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Green Jeep on November 29, 2010, 07:54:43 PM
Thanks, just had a look on ebay, will go for that kit....
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Green Jeep on December 03, 2010, 09:01:08 AM
Got the flap kit.... still can't get warm air.... could it be a register or something else?

Thanks again, Maf
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Mike Pavelin on December 03, 2010, 09:09:01 AM
Put the HEVAC unit into diagnostic mode. Look on WJJeeps.com for details.
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Dutch on December 03, 2010, 09:10:03 AM
Apparently you can also retrieve fault codes from the airco-climate controll unit.

Would have to look in me instruction book how to do this.

Might be an idea  :017:

edit : beat me to it Mike  :icon_winkle:
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: big g on December 03, 2010, 09:28:25 AM
Nay wonder people still like their XJs.

Not the best time for no heat,hope you get it sorted soon.
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Bulldog67 on December 03, 2010, 12:19:30 PM
Nay wonder people still like their CJs, FSJs, M715s.

Not the best time for no heat,hope you get it sorted soon.

sorted ya typo for ya  :greggmo:
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Green Jeep on December 03, 2010, 01:42:28 PM
Thanks guys...

Will get it plugged in and see what it throws up... getting a small amount of warmth come through... but clearly need more.... Cheers Maf
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: carljh on December 04, 2010, 12:12:55 PM
try reverse flushing the heater matrix with a hose pipe.
dont turn the tap on too much, just a gentle flow.
when it runs clear swop the pipes round and flush the other way.
repeat till it runs clear both ways.
when i did mine i used two lengths of 15mm plastic plumbing pipe as the heater pipes
fitted over it tight enough not to leak too much
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: Green Jeep on December 16, 2010, 09:58:41 PM
try reverse flushing the heater matrix with a hose pipe.
dont turn the tap on too much, just a gentle flow.
when it runs clear swop the pipes round and flush the other way.
repeat till it runs clear both ways.
when i did mine i used two lengths of 15mm plastic plumbing pipe as the heater pipes
fitted over it tight enough not to leak too much


Top tip, thanks, getting warmer now as blend doors working properly... will flush matrix nad hopefully hot then....
Title: Re: 2002 WJ Grand Cherokee 4.0 blowing cold...
Post by: tim_aka_tim on December 16, 2010, 10:07:34 PM
will flush matrix nad hopefully hot then....

Be very careful messing with your nads