1997 Jeep Wrangler heater blower

Tiny
BMICHELE
  • MEMBER
  • 1997 JEEP WRANGLER
Heater problem
1997 Jeep Wrangler 6 cyl Four Wheel Drive Automatic

My heater blower motor went in the spring. I didnt fix it or use it until a few weeks ago, when I finally fixed it. Now I don't have the blow power that I used to have! At first it wasn't working at all. Then we did something to one of the vac lines and it works a little bit now. Ie: when it is on high it blows like it is on low. We don't know where to look. Is there something wrong with the vac line? Or is there another line that we are missing?
Please help! It get very cold here!
thank you,
michele
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Monday, November 17th, 2008 AT 12:06 PM

26 Replies

Tiny
RACEFAN966
  • EXPERT
Now do you have 3 speeds or just one? If you only have one speed then the blower motor resistor might be your problem. Get back to me and we will go from there.
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Monday, November 17th, 2008 AT 4:17 PM
Tiny
BMICHELE
  • MEMBER
I have 3 speeds, low med & high. Before the blower motor went in the spring it was working great. It would heat the whole jeep in 10 min in really cold weather. Now when its on high it sounds like low and there is very little blowing out, almost like something is blocking it. In fact, thats what we thought the problem was (it wasnt blowing at all at first) until we found the vac, and it started working to where it is now.
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Tuesday, November 18th, 2008 AT 8:03 AM
Tiny
RACEFAN966
  • EXPERT
Ok so do all three speeds work now or is there only one speed now? There is no cabin air filter on this so that won't be a problem. Did you park the Jeep for a long period of time by chance? There isn't a chance that a critter built a nest in the heater box? Just checking I run into in more often then you think. Just trying to cover anything. Get back to me and we will go from there.
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Wednesday, November 19th, 2008 AT 12:05 AM
Tiny
BMICHELE
  • MEMBER
I don't think they all blow, and there is so little heat blown out when its on high-that is where I leave it.
I drove the jeep all summer long, I just never used the blower. When the old blower motor was in there I used it until it wouldnt work anymore, then summer was here so I didn't use it all summer. So of course as it started getting colder and I needed heat I had to replace it. So there is no chance that something built a nest in there.
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Wednesday, November 19th, 2008 AT 6:44 AM
Tiny
RACEFAN966
  • EXPERT
Ok great I would like you to pull the blower motor resister and see if it looks ok. See the resistor sets the speeds and when the old motor was pushed to its max use it may have demanded to much voltage therefore the resistor did its job and blew on or more coils leaving you with one speed. Here is what yours looks like. It should be bolted to the heater box close to the blower motor. You can check for resistance with an ohm meter to see if there is continuity.


http://www.2carpros.com/forum/automotive_pictures/249564_710141_1.jpg

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Wednesday, November 19th, 2008 AT 11:19 AM
Tiny
BMICHELE
  • MEMBER
But we replaced the blower motor. My husband said that the resistor is in that.
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Thursday, November 20th, 2008 AT 7:20 AM
Tiny
RACEFAN966
  • EXPERT
Sorry no it is not it is in the heater box. It will be near the blower motor but it is not part of it. Look for the part that looks like the pic that I sent you and check it. Let me know what you find.
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Thursday, November 20th, 2008 AT 10:36 AM
Tiny
BMICHELE
  • MEMBER
Ok, we are going out right now to look it over.
Also, my jeep has a/c that hasnt been used in years
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Thursday, November 20th, 2008 AT 11:44 AM
Tiny
BMICHELE
  • MEMBER
So far this is what I have -
there is 3 settings - low, med & high. You can hear and feel the speed change when u turn the switch setting from lowto high. It just doesnt blow like it used to. And when u turn on the recirculate it blows louder, but it doesnt really come out anywhere that it should be - u cant feel it in the vents.
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Thursday, November 20th, 2008 AT 1:17 PM
Tiny
RACEFAN966
  • EXPERT
Ok lets do a test on the wiring and see if the right voltage is getting to it. You could have a bad motor too it does happen sometimes. Ok first make a jumper wire and disconnect the plug from the blower motor and connect battery voltage to a connector on the motor itself and see how it works then. Here is a vacuum diagram for the heater system too.


http://www.2carpros.com/forum/automotive_pictures/249564_heater_vacuum_1.jpg


Let me know what you find and we will go through the next step and check the switch ok. Thanks again.
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Thursday, November 20th, 2008 AT 9:50 PM
Tiny
BILLDOG103
  • MEMBER
May I offer my 2 cents. I beleive you have a vacuum leak. The fact that you can hear the fan change speeds tells me that all electrical problems are ruled out. The air is blown into the heater box and then distributed to vents or defroster by a few doors actuated by vacuum switches. The doors remain closed until opened by the respective vacuum switch. This would explain why the fan blows but no air comes out. The vacuum switches are located under the dash board to the right of the gas pedal. You should be able to see them move when you switch from defrost to foot well heating modes. The recirculate option is operated by cable and would work even if you have a leak. Please switch between foot well to vent to defrost and let me know if you hear the sound (muffled thunk) of the doors closing. Or cram your head up into the drivers foot well and crane your head up to the right and then make the changes to see if the vacuum switches move. The first option is easier. Good luck.
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Monday, December 8th, 2008 AT 11:31 AM
Tiny
BMICHELE
  • MEMBER
Thanks. We still are having the same results. We thought it was a vac leak-it still may be. As you said you can hear the doors opening and closing when you turn the recirculate on, so that does open, and that doesn't give good heat either. It sounds like it wants to blow but there is a blockage somewhere. Someone else suggested flushing the system.
We didnt realize the doors were on that side, so we are going to do that first, and I will let you know what we get! Thanks again. Its zero degrees here so its a bit frustrating!
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Monday, December 8th, 2008 AT 1:16 PM
Tiny
BILLDOG103
  • MEMBER
Well I feel your pain... I have been there. I live in New England so it gets cold but usually doesn't stay too bad for long. Here is a picture of the vacuum switches. They probably won't be arranged exactly like this because the image is from a 99 but it is a good representation. You can try to remove an actuator arm and open the door manually. I don't know if it will stay open but if it defrosts your feet it is worth a try. Good luck and let us know how you make out. The photo is from a write up on www.stu-offroad.com Just want to give props. The Vacuum switches are on the left hand side of the yellow box.


http://www.2carpros.com/forum/automotive_pictures/283274_Capture_1.jpg




http://www.2carpros.com/forum/automotive_pictures/283274_Capture1_1.jpg




http://www.2carpros.com/forum/automotive_pictures/283274_htrcore31_1.jpg

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Monday, December 8th, 2008 AT 2:59 PM
Tiny
BMICHELE
  • MEMBER
Ok, we checked out all of those and they are all working fine everything is running smooth under there. We are going to try flushing the system. Idk what to do next!
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Thursday, December 11th, 2008 AT 3:18 PM
Tiny
BILLDOG103
  • MEMBER
Flushing will only clean out the inside of the heater core itself and would give you more heat if you didn't have much. It will not improve air flow. If all of the diverters are opening and no air is coming out. The only other thing to check is upstream. There must be a blockage before the blower. You could remove the cowl and look in that area. That is where the air is drawn from. Maybe a critter made a nest in your heater box. I believe you said that your husband replaced the blower motor. I think you need to have a look at what happened during that procedure. Pull it out and power it up on a bench. Make sure the squirrel cage is spinning. Stick your hand into the hole and feel around (with the engine off and the battery terminal remove to be extra safe).
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Thursday, December 11th, 2008 AT 3:44 PM
Tiny
BMICHELE
  • MEMBER
Ok. We took the blower motor back off and the squirrel cage is working fine. There was some pine needles in by the heater core and we cleandd it all out but it did not do anything to change the heat blowing. Could the heater core stop air flow if it was plugged or something?
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Tuesday, December 16th, 2008 AT 10:40 AM
Tiny
BILLDOG103
  • MEMBER
The heater core looks like a mini radiator...


http://www.2carpros.com/forum/automotive_pictures/283274_getimage_1.jpg



Air Flows through it and removes heat from the fluid that circulates inside it. If it were the cause of the airflow problem, when you switch to cool air on the heater control panel then the air would bypass it and flow unobstructed.
You checked the vacuum switches up under the dash in the drivers foot well area? They move when you switch from defrost to vents to footwell? Try this on the lowest fan setting in case they are very week.

Lets start this over...
1. The fan operates on all the different speed settings?
2. no air comes out of any of the selectable areas (ie defrost, foot well, vents, combination settings)
3. The vacuum switches move when switched between selectable areas (i.e. defrost, foot well, etc...)
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Tuesday, December 16th, 2008 AT 11:52 AM
Tiny
BILLDOG103
  • MEMBER
The only place left to look if all of the other problems turn up negative is the cowl. This is the grill like piece right in front of the windshield. Remove the wiper arm and 4 screws and it should come out (never done it myself) This is where the air come in. Check for an obstruction there.
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Tuesday, December 16th, 2008 AT 12:04 PM
Tiny
BMICHELE
  • MEMBER
Ok
1-yes you can hear the fan change speeds.
2-very little heat comes out of any of them, not enough to warm you
3-the vacuum switches do move when switching from the different areas

We stuck something down the defrost and it seemed to do all the way in.
I am thinking the only place left is between the heater core and where the ductwork is. That doesnt seem like much area.

I will check the cowel and see what I get
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Tuesday, December 16th, 2008 AT 2:23 PM
Tiny
BILLDOG103
  • MEMBER
Very little heat or very little air? Or both?
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Tuesday, December 16th, 2008 AT 2:29 PM

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