Electrical problem
2004 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 60500 miles
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I changed the battery in my Grand Cherokee and to keep the clock on time and other things from happening, I connected another battery to the battery leads when I removed the dying battery. Installation seemed to go perfectly, but when I drove the vehicle two problems, that were not present before, were manifested:

1) Cruise Control light appears on dash when I press the on button, but it will not engage.
2) Mode control (recirculation, floor, floor/vent, vent, defrost, etc.) does not work. All heating or air conditioning comes out of the windshield defrost louver.

I checked the fuses in the cab and under the hood, all tested OK.

Any help would be greatly appreciated.

Thanks
Paul

I am having the exact same problem with my 2003 jeep grand cherokee. I took it to the mechanic for rotors and breaks with an oil change and now all these new problems.... something is fishy. Someone please help!

HERE IS A POSTING FROM ANOTHER SITE>>>>>>>>>>>>>>>>>>>>>>

I posted on Thursday about my 2001 Cherokee Sport - thought I would give an update on here that may help someone else.

After thinking about things alittle more -
Symptoms -
* All air going to defroster mode
* Cruise Control not functioning
* Check engine light on. Code decoded as "small vacuum leak"

Well, I had been researching and know that the air blend doors are vacuum controlled. I discovered that the Cruise Control is also vacuum controlled. This along with my check engine light "small vacuum leak", led me to believe that all are related.

As this is my wifes vehicle, I am not sure if all happened at the same time or not. As most know alot of women do not pay attention to anythingto have details to provide the husband in proper diagnosing - other than "it dont work - fix it"

I pulled it into the shop yesterday and just looked under the hood not knowing where to start. I mean, a vacuum leak doesn't flash a red light saying fix me... So after another cold beverage, I started pushing and pulling on vacuum lines, disconnecting and blowing in them. Nothing! Ok, another cold beverage ... I grabbed another line and was disconnecting a line from a t-fitting and the whole thing came loose... the end was broke - WaLa ! It was the vacuum line that runs inbetween the passenger fender wall and the battery behind the headlight. What had happened I assume is, because the tie that held it to the fender was broke, is when I changed the battery last year, the line was in the way and broke ? So I made a hose patch for it, got it all back to gether and checked it out - No more check engine light, got air in all directions!

So, I tell the wife to come out and I need her help. I told her to get in and start it and wait for my commands... She gets in (I set the ac to max), starts it and looks at me, I just stand back for a sec - finally she realizes she has ac blowing in her face ! Then I had to point out the engine light... I took a drive and the cruise now works as well !

Well, I got lucky ad found where my vacuum "leak" was and got it fixed.

Time spent researching: 2 hours
Time spent repairing: 30 minutes
Total cost:.25 cents (tape and piece of hose)
Wife having A/C: Priceless !!!