A_Jeepr

Alright, its never worked right, and 15* and no heat isn't fun.

Technically I got heat, but only the defroster puts heat out. When I put the fan on high the fan or something whistles.

When I go to switch the heater control: OFF - MAX - NORMAL - BI-LEVEL - VENT - HEAT - DEFROST....no air comes out of any of the vents on the top of the dash, or for your feet. Only the defroster puts out heat.

I think its vacuum problem, but I am not sure where. All the connectors in the engine bay don't seem to be leaking. I reached 2 of the vacuum solenoids under the dash and checked the connections there, both were ok.

I some how fixed it awhile back to where if I didn't use half throttle the heat would still blow (also has the "part-time" indicator on the light on and when it went off while applying 1/2 throttle, the heat would do the same) Now its back to where it was.

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Is there a diagram that anyone knows that shows the routing of all the vacuum lines?? Also I was told be someone to check my switch on the dash?

I hate vacuum problems, they are so hard to track down!

trapper

I was told that a coolant flush would go a long way in the area.. using CLR.. found at the grocery store

If this dosent work you will be replacing stuff anyway and for the minimal $ it wouldnt hurt


1- undo top and bottom radiator coolant lines
2- let drain to its new level
3- reattach lower coolant line
4- pour CLR in to the top hose until no more goes in
5- reattach top coolant line
6- top off with water in radiator
7- turn on truck and let run for 2 hours in driveway
wait for it.. wait foooor iiiiit....
8- undo upper and lower coolant lines
9- get out your garden hose and put in uppers coolant line.. turn water on
10- if water dosent run through the motor coolant system.. turn truck on and let the water pump do it for you
11- let run water and truck till clean (wash out the cunk knocked loose)
12- turn water off
13- turn truck off just shortly after the water getting some added water out of the motor coolant lines
14- reattach upper and lower coolant lines
15- fill with coolant specific to your region (might need antifreeze)
16- enjoy your heat inside the truck again

A_Jeepr

Ahem I ain't a dumbas. I have built several vehicles already. I know how to do system flushes, and I know I don't need to in this case, because I still get hot air, just its not coming out of the right vents. Sorry for the misunderstanding.

1995XJ_Sport

I have the same problem, it only blows out the defrost, and only on high, that is how mine is. I can turn it off though. I am also curious to see what might fix this.

confederate

Fan stuck on high is most likely a bad blower motor resistor. Its about $40 from Autozone. Mine is stuck on defrost also, but I havent had time to figure out what caused that yet, the fan speed was more important at the time lol

A_Jeepr

fans not stuck it only whistles when I switch it on high.

glad im not alone!

Abovetimberline

You said when you give it throttle that you have the issue then? If so it is a vacuum issue,the vacuum starts at the intake then to the resevoir in the bumper to the back of the climate controller,make sure there is good vacuum to controller sometimes they get plugged,it could also be the resevoir,they can crack,also there is a check valve in the resevoir to prevent loss of vacuum when you accelerate.

A_Jeepr

oh yeah my Jeep never had the A/C box checked. Non AC version.

its behind the bumper? so thats where it is! I will look for it/at it in the morning thanks.

A_Jeepr

ok I pulled the bottom half of my dash off and looked at the vacuum switches (that move the rods, thus the flaps) the vacuum connections look good. I can manually move the rods and feel the heat come out of the other vents.

However I held the rod lightly while taking my other free hand and moving the control on the dash and could not feel it move. I then held the vacuum thing and turned the Jeep off. I felt the rod move slightly.

This means I am getting vacuum, just not enough. Anyone have any clue as to why?

I still need to find that canister behind the bumper.

Willys55

That vacuum can should be under the right front fender near the bumber.

When you get those vents working, it might also fix your high blower whistle noise.

tgreene

Mine does the very same thing and I just recently discovered my vacuum reservoir is cracked. Unfortunately I haven't had a chance to fix it yet to tell you if that will fix your problem too.