Heat and AC only come out of defrost
06-14-2015, 04:46 PM
#1
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Year: 1995
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Heat and AC only come out of defrost
About two days ago, I noticed that the air would only come out of the defrost location regardless of the air setting and fan speed. What could be the issue?
06-14-2015, 06:09 PM
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06-15-2015, 07:27 AM
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Year: 1990
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06-15-2015, 08:08 AM
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06-15-2015, 08:10 AM
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06-15-2015, 08:13 AM
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I did some research last night, and I need to take a look at the check valve. But upon visual inspection, the line going into the intake manifold looks fine, and the vacuum reservoir looked fine, as well. I will probably relocate the reservoir, once I fix this leak.
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06-15-2015, 08:15 AM
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If you have a vacuum pump brake bleeder (Harbor Freight) you can run the system down and see if it holds vacuum. It only takes around 8 in/hg to operate the HVAC doors.
Hook up to the vacuum tap on the intake manifold (coupling with the check valve) with the vacuum pump and pump the system down and see if it holds.
Pump hook up on a '99 XJ....without engine installed :-)
06-15-2015, 08:36 AM
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So I found the leak and temporarily fixed it with electrical tape lol. Not sure how I missed it last night, but near the battery, there was a good size hole in the line. Now the air and heat comes out of the vents again. Where do you all recommend relocating the vacuum reservoir to under the engine bay?
While on topic though, I believe I read that the cruise control works on vacuum, as well. It has not worked, since I bought the Jeep last summer. No light comes on the dash either. What could be the issue?
While on topic though, I believe I read that the cruise control works on vacuum, as well. It has not worked, since I bought the Jeep last summer. No light comes on the dash either. What could be the issue?
Last edited by Jeep4L1fe; 06-15-2015 at 09:29 AM.
06-15-2015, 05:36 PM
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So I found the leak and temporarily fixed it with electrical tape lol. Not sure how I missed it last night, but near the battery, there was a good size hole in the line. Now the air and heat comes out of the vents again. Where do you all recommend relocating the vacuum reservoir to under the engine bay?
While on topic though, I believe I read that the cruise control works on vacuum, as well. It has not worked, since I bought the Jeep last summer. No light comes on the dash either. What could be the issue?
While on topic though, I believe I read that the cruise control works on vacuum, as well. It has not worked, since I bought the Jeep last summer. No light comes on the dash either. What could be the issue?
The same leak COULD be the cause of the cruise control being inoperative......
06-15-2015, 05:36 PM
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06-15-2015, 05:42 PM
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Cruise is still not working despite fixing the vacuum leak. It must be an electrical issue of some sort
06-15-2015, 06:17 PM
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So I found the leak and temporarily fixed it with electrical tape lol. Not sure how I missed it last night, but near the battery, there was a good size hole in the line. Now the air and heat comes out of the vents again. Where do you all recommend relocating the vacuum reservoir to under the engine bay?
There's no need to relocate the reservoir unless you are putting a different bumper on your Heep.
Use a section of hose to mend that tube. Cut the tube and slide a rubber tube over each end.
While on topic though, I believe I read that the cruise control works on vacuum, as well. It has not worked, since I bought the Jeep last summer. No light comes on the dash either. What could be the issue?
There's no need to relocate the reservoir unless you are putting a different bumper on your Heep.
Use a section of hose to mend that tube. Cut the tube and slide a rubber tube over each end.
While on topic though, I believe I read that the cruise control works on vacuum, as well. It has not worked, since I bought the Jeep last summer. No light comes on the dash either. What could be the issue?
It does work on vacuum but if you don't get a light on the instrument cluster it may mean that the cruise switches on the steering wheel are defective. Does the Cruise annunciator light up when you turn the ignition switch to RUN, just before cranking?
06-15-2015, 08:02 PM
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I'll have to double check, but I'm pretty sure that it does not light up at all.
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