Topic: heater question

[gomi]

Okay, so I was driving home in the rain and it was kind of hot in the jeep. Normally I would just roll down the windows but since it was raining I turned on the air. I don't have a/c but I figured it would still blow cooler air in the jeep. For some reason, it was blowing hot air even though the knob was set all the way to the coolest position. SHouldn't it be blowing cooler air. The air was just as hot as if the heater was on max. any Ideas?

[Jeffy]

It sounds like the heater core might be stuck on even thought the fan might be off.

[Guardian7]

My 89 YJ has the same problem and was stuck on heat and now it's stuck on cold so I will be looking at this issue and let you know what I find out. By the way, what year is your Jeep?

[Jeffy]

My 89 YJ has the same problem and was stuck on heat and now it's stuck on cold so I will be looking at this issue and let you know what I find out. By the way, what year is your Jeep?

YJ's have the vacuum line that connects to a white manifold that sits above the ashtray on the driver side.

[gomi]

My 89 YJ has the same problem and was stuck on heat and now it's stuck on cold so I will be looking at this issue and let you know what I find out. By the way, what year is your Jeep?

mine is a 99

[Jeffy]

My 89 YJ has the same problem and was stuck on heat and now it's stuck on cold so I will be looking at this issue and let you know what I find out. By the way, what year is your Jeep?

mine is a 99

I think they are still vacuum controlled.  I think in a leak sinario it should close the flow through the core.

[dunklervogel]

I seem to have that problem too..
it has went both ways, always hot and always cold.

[Guardian7]

Gomi, your 99 is most likely a lot different from my 89, do you have a Haynes Manual to read on the task? Here is a link to 99 factory service manual heating & Air section;
http://www.vintagemusicprojects.com/jeep/servicemanuals/TJ98/ETJ_24.PDF

Okay, just got done tearing my dash apart and heater control which revealed multiple problems. First I found a cable on the underside of the heater control console completely off which was a bear to re-attach, I actually bent the hook down with pliers to attach cable then bent it back into place, next the 3-way switch was broken loose from it's plastic mounting so for now it will stay in the high position until I can replace the part. Looked at the vacuum switch which had only 2 lines on it but a connection for a third line was empty and found no 3rd line so left it like it was. Since I was in there I pulled the center gauge cluster out and fixed my intermittant clock which had bad solder joints, cleaned and re-assembled everything in time for dinner!
I now have everything working except the blower speed control is just high or off. I must say 2 things impressed me, the control cables are very stout gage braided steel with heavy metal loops on each end, the intrument gauge cluster seems very well built with all brass hardware holding each gauge in place and a unique power connect setup on each gauge.

[gomi]

Thanks so much guys, I'm going to try and fix it today seeing as I have it off.

[chardrc]

i guess this is the best place of any to ask this. esopecialy with guardian here with a 89 yj.. i have a 1990 jy 2.5 and on the control lever for defrost, heat, or vent, the level will only go between off, defrost, and heat.. but wont go into vent unless you reakly jam it and strach siomthing(maybe the cable). so is the vent selection area only soposed to be for jeeps with ac or is this odd.. vent as all the way right on mine.

[Jeffy]

i guess this is the best place of any to ask this. esopecialy with guardian here with a 89 yj.. i have a 1990 jy 2.5 and on the control lever for defrost, heat, or vent, the level will only go between off, defrost, and heat.. but wont go into vent unless you reakly jam it and strach siomthing(maybe the cable). so is the vent selection area only soposed to be for jeeps with ac or is this odd.. vent as all the way right on mine.

Look at the actual vent.  It's easy to see on a YJ.  You can see the cable and where it pulls the lever.  The lever is probably bent a little and is binding.

[Guardian7]

They all have vent positions, AC or not, you should also check each cable end which is the most likely place for a cable to get bent but, the root cause may be due to a lever binding on the heater box or ducting.

[chardrc]

i looked at the cabels and levers yesterday and the one for the heatrer bos is ok.. but the one that selects off, defrost, heater, adn vent is messed up and i dont know why...

first off when you get to the heater position the cable has already pulled the lever thing it pulls as far ass it goes adn if you force it into the vent position the fan turns off as if you selected off... so ill have to somehow crawl under the dash more to see what is the isue.. or jsut take it abart...


ow ya and oddly enoguh i found a conecter behign the dash to the left of the control panel for the heat/vent. it has 3 wires.. i think they were green, white and black...(might be wrong but i know there was green).. and it ahs one of those exspanding plastic things for pushing into a hole to hold it someweer but i couldnt find andywere to plug it into...... arrr looks like i need to take my dash apart agian...

[Jeffy]

i looked at the cabels and levers yesterday and the one for the heatrer bos is ok.. but the one that selects off, defrost, heater, adn vent is messed up and i dont know why...

first off when you get to the heater position the cable has already pulled the lever thing it pulls as far ass it goes adn if you force it into the vent position the fan turns off as if you selected off... so ill have to somehow crawl under the dash more to see what is the isue.. or jsut take it abart...


ow ya and oddly enoguh i found a conecter behign the dash to the left of the control panel for the heat/vent. it has 3 wires.. i think they were green, white and black...(might be wrong but i know there was green).. and it ahs one of those exspanding plastic things for pushing into a hole to hold it someweer but i couldnt find andywere to plug it into...... arrr looks like i need to take my dash apart agian...

Check out the 94 or 95 fsm's.  The vents should be exactly the same.

[Compstall]

I admit I haven't taken anything apart yet, but could this be the same type of problem, i.e., I can't get air to come out of the defrost vents.  The other positions work, but you can tell the blend door is flopping around in there because once you turn the fan on high it will bang into position.  However, no matter what I do, I can't get more than residual air through the defroster vents.