A/c turns off on cruise? - JeepForum.com
 
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post #1 of 12 Old 09-13-2012, 12:54 PM Thread Starter
98zjay
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1998 ZJ 
 
Join Date: Aug 2011
Location: Louisville
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A/c turns off on cruise?

Does anyone have a logical explanation why my a/c cuts off when I go up hills on cruise control??? I tap te brakes to release cruise and the air comes back on. Is this a computer configuration to draw more power for the hill or something? Bit annoying honestly. Gets toasty sometimes!


2000 tj 4.0 nv3500 5spd 2"bb+1.25 bl 33x12.5 MTR's Dana 44
98 zj 4.0 stock
98 ZJ 5.2L 4.5" IRO w/ 32" km2's and lots of goods-sold
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post #2 of 12 Old 09-13-2012, 01:07 PM
PolkaPower
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1998 ZJ 
 
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Location: The Abyss
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The cruise and ac work off of the same vac line maybe. Is there a leak?
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post #3 of 12 Old 09-13-2012, 01:27 PM
moggie99
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Sounds like a Leak in the vacuum line. The blower reverts to defrost vents when there is insufficient vacuum.

Richard Moss
'96 ZJ 4L auto, '95 XJ 4L manual, 2000 Nissan Patrol Y61
In the UK: 1969 MGC GT
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post #4 of 12 Old 09-13-2012, 01:51 PM Thread Starter
98zjay
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Yea that's what it does. It goes to defrost

2000 tj 4.0 nv3500 5spd 2"bb+1.25 bl 33x12.5 MTR's Dana 44
98 zj 4.0 stock
98 ZJ 5.2L 4.5" IRO w/ 32" km2's and lots of goods-sold
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post #5 of 12 Old 09-13-2012, 01:52 PM Thread Starter
98zjay
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Where's the line to check??

2000 tj 4.0 nv3500 5spd 2"bb+1.25 bl 33x12.5 MTR's Dana 44
98 zj 4.0 stock
98 ZJ 5.2L 4.5" IRO w/ 32" km2's and lots of goods-sold
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post #6 of 12 Old 09-13-2012, 02:01 PM
PolkaPower
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They are the plastic lines on the pass side. They go to a junction under the battery tray. You will probably want to take that out to inspect it.
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post #7 of 12 Old 09-13-2012, 03:13 PM
Glasssplinter
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1994 ZJ 
 
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Dealing with the same problem right now. There was a thread recently that showed the TSB on this. It involves installing a check valve for the line going through the firewall. Going to get this done tonight and hopefully have it fixed. Other vacuum line didn't have any leaks on it.

'94 ZJ, 4.0L, 231 TC
Icom V-8000 with 1/4 wave
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post #8 of 12 Old 09-13-2012, 07:35 PM
jorhay
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Garage
yeah, I've had this issue for years. Had a check valve installed a month or so ago, helped, but the Jeep still does it. guess I need to go over all of the lines, again.
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post #9 of 12 Old 09-13-2012, 08:10 PM
jtackerman28
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Quote:
Originally Posted by Glasssplinter
Dealing with the same problem right now. There was a thread recently that showed the TSB on this. It involves installing a check valve for the line going through the firewall. Going to get this done tonight and hopefully have it fixed. Other vacuum line didn't have any leaks on it.
Where did you get the check valve?

3.5 re lift, double sheer front tb, 31" wrangler duratecs
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post #10 of 12 Old 09-14-2012, 02:43 PM
Glasssplinter
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O'Reilly has them but I'm sure any auto parts has one. It was just in the little blister pack Help! area. Part # 47149 $4.99 but needs some hose to connect it and make it seal. Installed it but have yet to test it on a road trip.

'94 ZJ, 4.0L, 231 TC
Icom V-8000 with 1/4 wave
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post #11 of 12 Old 09-15-2012, 09:53 AM
moggie99
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My ZJ has been doing this for a while and today I have just discovered that the vacuum actuator for the recirc door has failed. The vacuum supply to it is good but it appears that the diaphragm inside has split because the actuator doesn't move when the vacuum is applied. Because I mostly use the thing set on recirc due to the heat here, the failed diaphragm seems to be allowing air into the system. I'm just off for a test drive with the recirc set off (no vacuum to the actuator in this mode) to see if that allows the rest of the system to work properly.

Richard Moss
'96 ZJ 4L auto, '95 XJ 4L manual, 2000 Nissan Patrol Y61
In the UK: 1969 MGC GT
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post #12 of 12 Old 09-15-2012, 12:18 PM
moggie99
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That worked - with the recirc OFF (and therefore no vacuum demand from the damaged actuator) the rest of the system worked properly. Now to buy a new recirc actuator.....

Richard Moss
'96 ZJ 4L auto, '95 XJ 4L manual, 2000 Nissan Patrol Y61
In the UK: 1969 MGC GT
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