no heat in my 5.9

[broark39]

i have 98 gc 5.9, recently my heat just quit, it has the automatic temp control, digital display reads hi, fan works on all speeds, you can change to defrost, vent , floor. it just blows cold air, any ideals

 

[jimbob2001]

A couple of suggestions on this one: If your Jeep has the Auto Temp Control (as you mentioned). Might want to look at: Blower Motor Controller and OR your Blend Doors. By the way---- There are SOME EXCELLENT Posts on this Board dealing with this Topic (might want to do a SEARCH). Just a Suggestion. Auto Temp System is also referred to as: AZC (Auto Zone Control) The problem you describe is a FAIRLY common failure! --- JB

 

[broark39]

thanks for the tips, i'll give them a try

 

[broark39]

does anyone know an easy way to check blend door or blower motor controler on 98 gc, also every now and then the information center says bad coolant sensor, it doesn't say it all the time. if it is bad could this cause my problem

 

[jimbob2001]

Well. There are a FEW possibilities --- ON this " NO HEAT" Problem. Let's start Simple and Work UP from there. 1. Is your Thermostat WORKING OK? (195F). After Jeep warms up -- Is Coolant Temp Normal? 2. Heater Core OK? When Jeep Is Hot -- Can You feel WARM water in BOTH Heater Hoses -- That go thru Firewall? Are the BLEND Doors -- Actuating -- When you select HEAT? Common Failure is: Blend Doors and Actuator Housing (Has Blend door Motor ) This is NOT a. Simple Fix! Did you Research the POSTS on this Board. -- As I suggested? Quite a few POSTS on this Problem. The Dealership (AKA: Stealership) will want about an ARM and a LEG! -- JB

 

[broark39]

coolant temp. is normal,both heater hoses are hot. i don't know if blend doors are actuating, how can you tell? i looked at some post didn't see same problem

 

[broark39]

i guess i'm just going to put on extra sock's and underwear and tough it out

 

[jimbob2001]

You can HEAR the BLEND Doors moving--- From Stop to Stop. (Full Heat to Full Cool) Warm the Jeep up---Bring to Normal Temp. Roll Windows Up -- Should be in Quiet Area. Command FULL HEAT --- Then Command FULL COOL. Repeat a FEW times. Did you HEAR the Blend Doors Move Each Time?? IF NOT --- You have a Blend Door - Actuator Problem. Next--- when you Command Full Heat or Cool --- Does the Drivers Side AND the Passengers Side BOTH have the SAME Temp. AIR?? Also --- You may want to go to Dealer -- have him DIAGNOSE the problem-- Nominal Fee. Then You will know for sure. The 5.9 is a Special Model -- Many of the Parts are unique to that Jeep. Chances are pretty GOOD -- It is the Blend Doors and or the Actuator Housing. Common Problem in the GC Jeep. Good Luck! --- JB. P.S. - Many Sites Exist on the Internet ---Deal with this Problem.

 

[broark39]

i know the blend motor is working.something curious though, when in the defrost mode hot air is coming out the floor vent but cold air out the defrost vent, when you change to any other mode its cold air. funds are tight right now but i will probably end letting dealership diagnose the problem. thank you jimbob2001 for your help.

 

[jimbob2001]

Well --- You are most certainly welcome. At LEAST you have Hot Air in ONE Mode ( although it is the Wrong Vent!). I think You have made a Wise decision -- The Problem still SOUNDS Like a Blend Door Issue. You can GOOGLE the Blend Door problem --- And GAIN some Additional INFO on this Issue! --- Comments? JB

 

[broark39]

Finally figured out what the problem is. A plastic gear in the blend motor actuator is broke, it turns a little but not all the way. if anyone knows a good web site or if anyone has one ( motor) i would really appreciate your help.

 

[jeep4jason]

I have probably 3 out of 5 front vents that blow heat and air out like they are supposed to. I have an 04 WJ. Any suggestions?

 

[broark39]

im not sure but jimbob2001 was a big help for me.he mentioned that in one of his replies to me but that wasn't my problem so he didn't go into detail.