Rough idle while in park, with heat on
04-28-2015, 02:49 PM
#16
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Join Date: Aug 2010
Location: Canton, MI
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Year: 1999
Model: Cherokee
Engine: 4.0
Thanks, Ken. I'll have to give that a try. I thought this one was weird too. I'll try and make it happen again, and maybe pass on some more detail.
Since you brought up the NSS, I noticed my reverse lights delayed to come on when it was cold outside, but my XJ always started in park. Then when it was REALLY cold, it would throw a CEL and I had no OD until I turned it of for a couple minutes, then back on and OD was back. This only happen 3 or 4 times all winter. This past weekend, I wanted to take it off and give it a good cleaning, but for the life of me couldn't get it off the shaft. Anyone have any ideas on hoe to get it off without breaking it? Considering it works fine unless it's crazy cold out, I don't want to damage it.
Since you brought up the NSS, I noticed my reverse lights delayed to come on when it was cold outside, but my XJ always started in park. Then when it was REALLY cold, it would throw a CEL and I had no OD until I turned it of for a couple minutes, then back on and OD was back. This only happen 3 or 4 times all winter. This past weekend, I wanted to take it off and give it a good cleaning, but for the life of me couldn't get it off the shaft. Anyone have any ideas on hoe to get it off without breaking it? Considering it works fine unless it's crazy cold out, I don't want to damage it.
What I forgot to mention in my post about pulling fuse #6, is that we're trying to isolate an electrical problem from a vacuum problem
With the fuse pulled, run the engine, shifter in Park, move the mode selector from OFF to all the selections. See if the engine acts up. If so, it could be a vacuum issue, if not it's probably an electrical issue.
See the schematic below.
You can see that the moment you turn the key to RUN, the blower relay is pulled in, putting power through the blower then up to the mode selector. The blower is looking for a ground to operate and the Mode Selector does that. If the mod selector is OFF the circuit is inop and the blower doesn't run but power is still available through the entire circuit, up to the Mode Selector.
Below is a pic of the back of a '99 Climate Control Panel. Yours will have a push-pull cable attached to the back. '99 did away with that but the vacuum tubes you see in the pic are still there.
With the fuse pulled and if you run the Mode Selector through the settings and it acts up then it can be assumed there's a vacuum issue.
Schematic:
Back of Climate Control Panel:
04-28-2015, 06:16 PM
#17
CF Veteran
Thread Starter
Thanks again! I hate to sound ignorant, but I'm pulling this fuse from the fuse box in the engine compartment, right? I'm knew to working on my vehicle, but I'm mechanically inclined and learn quick. I want to be able to do as much work/troubleshooting on my jeep as possible.
By the way... GO WINGS! Just noticed you're in Michigan. Hopefully they can pull out this game 7 tomorrow.
By the way... GO WINGS! Just noticed you're in Michigan. Hopefully they can pull out this game 7 tomorrow.
04-28-2015, 06:35 PM
#18
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Year: 1999
Model: Cherokee
Engine: 4.0
Thanks again! I hate to sound ignorant, but I'm pulling this fuse from the fuse box in the engine compartment, right? I'm knew to working on my vehicle, but I'm mechanically inclined and learn quick. I want to be able to do as much work/troubleshooting on my jeep as possible.
By the way... GO WINGS! Just noticed you're in Michigan. Hopefully they can pull out this game 7 tomorrow.
By the way... GO WINGS! Just noticed you're in Michigan. Hopefully they can pull out this game 7 tomorrow.
Yes, the fuse box in the engine compartment is called the Power Distribution Center (PDC) and the fuse panel in the passenger foot well is called the Junction Block (JB). Most of the fuses in the JB are powered when the ignition switch is turned to RUN/START, and the fuses in the PDC are powered directly from the battery/Alternator.
Go Wings indeed. But I don't have my hopes up.
04-28-2015, 06:51 PM
#19
CF Veteran
Thread Starter
Yes, the fuse box in the engine compartment is called the Power Distribution Center (PDC) and the fuse panel in the passenger foot well is called the Junction Block (JB). Most of the fuses in the JB are powered when the ignition switch is turned to RUN/START, and the fuses in the PDC are powered directly from the battery/Alternator.
Go Wings indeed. But I don't have my hopes up.
Go Wings indeed. But I don't have my hopes up.
I must say, my hopes are a little low too. Unfortunately, Kronwall is suspended for game 7 because of the hit he gave last night. I got faith in our boys though! We've already won two in Tampa.
Thanks again, I'll be sure to post my findings.
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