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XJ Ask the Question Thread
Junior Member
Joined: Dec 2012
Posts: 90
Likes: 0
From: Fredericton, New Brunswick, Canada
Year: 2000
Model: Cherokee
Engine: 4.0L
Hey i have a 00' xj 4.0l and my heater switch only works on 4 and not the other settings, its getting annouying as my jeeps heater only blows air on the highest setting, does anyone have a fix for this?
CF Veteran
Joined: Aug 2011
Posts: 1,090
Likes: 0
From: Lehigh Valley, Pennsylvania
Year: 1999
Model: Cherokee
Engine: 4.0 stroked to 4.6, Thanks to Teasdale'sMachine!
The fan resistor located in the bottom of the HVAC box is the most likely culprit.
Old School CF Moderator
Joined: May 2010
Posts: 9,652
Likes: 3
From: Chattanooga
Year: 2001
Model: Cherokee
Engine: 4.0
Changed my oil and filter from a wix to a mopar and my oil pressure went up noticeably..is this too high?? It may be important to note that the oil wix filter was stuck on the assembly so well that i had to hammer part of it..then use a band wrench.
This was with the engine at around 160ish on my way to work. Usually it is pretty steady at just 40.
This was with the engine at around 160ish on my way to work. Usually it is pretty steady at just 40.
Last edited by Xj88; Feb 25, 2013 at 07:15 AM.
Changed my oil and filter from a wix to a mopar and my oil pressure went up noticeably..is this too high?? It may be important to note that the oil wix filter was stuck on the assembly so well that i had to hammer part of it..then use a band wrench.
This was with the engine at around 160ish on my way to work. Usually it is pretty steady at just 40.
This was with the engine at around 160ish on my way to work. Usually it is pretty steady at just 40.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
88 xj 4.0 4x4
Need quick answer.
Had this problem before, sprayed engine down avoiding alt, diZzy, and major electrical. Used low pressure.
Now i have extremly high idle. Like 3k+.
Iv got no vaccum leaks, unplugged the idle controle motor next to tps with out and change in idle. When open up the throttle the idle just goes higher.
I have no tools with me and im stuck at the car wash with a idle that will kill me if i try to drive it home.
Need quick answer.
Had this problem before, sprayed engine down avoiding alt, diZzy, and major electrical. Used low pressure.
Now i have extremly high idle. Like 3k+.
Iv got no vaccum leaks, unplugged the idle controle motor next to tps with out and change in idle. When open up the throttle the idle just goes higher.
I have no tools with me and im stuck at the car wash with a idle that will kill me if i try to drive it home.
Pop off every connector under the hood and let them dry out with AIR. Naturally, shop air, or those duster cans. Once the water's gone reassemble everything and see how it runs. If it's still crap I suspect the TPS like others. Cruiser54 has a nice writeup of checking it with a multimeter.
It's always a good idea to perform a connector refresh, especially on a Renix with that C101 nonsense:
1. Disassemble some connection
2. Attack the pins and socket with a brass wite brush if small, if a large cable (battery, ground, etc) use sand paper. Scrub the crap off. Be careful to not rip any seals or damage the connector.
3. If the connector has pins or blades, look into the socket side and notice the receptacle. Using a dental pick you want to grab that metal and bend it towards the middle, so that it has a better grip of the pin or blade.
4. Clean out all the residues and dust with Electrical Contact Cleaner, I prefer the hexane or heptane based ones as they actually work and aren't as carcinogenic. Spray until the stuff dribbles out.
5. Let the connector dry naturally or help it along with some air.
6. Apply a very light amount of an actual conductive electric grease to the mating surfaces to improve the connection and prevent corrosion. The most noticeable place for this stuff is the buttons on top of spark plugs and the distributor, a real electrical grease will promote conductivity and lessen the welding. My favorite is SanChem NO-OX-ID but you can find products like Gardner Bender's OX-GARD and Ideal's NOALOX at Home Depot, Lowe's, etc. This list is a handy reference: http://www.k1ttt.net/technote/antiox.html
7. Apply a liberal amount of dielectric grease to the edge of the connector. If this connector has a shroud apply it around the shroud. For some connectors like the fuel injectors, the dielectric grease will lubricate the little rubber gasket and keep water out. Same for spark plug wire boots. This stuff is non-conductive and should never be used directly on a pin or socket if you can avoid it. Basically a caulking that never dries.
8. Reassemble the connector and admire your handywork.
9. Repeat until out of connectors.
Do not use WD-40 on your electrical systems. Lol
Senior Member
Joined: Sep 2012
Posts: 553
Likes: 0
From: Chesapeake Beach, MD
Year: 2001
Model: Cherokee
Engine: 4.0L Inline 6
I am contemplating changing all brake lights, reverse lights, turn signals, and side markers to led lights, can I just buy new bulbs and plug and play so to speak or do I need to add load resistors?
CF Veteran
Joined: Sep 2012
Posts: 1,289
Likes: 0
From: Springfield Virginia
Year: 1998
Model: Cherokee
Engine: 4.0
Back up lights and brake lights should be fine with just the LEDs. Turn signals on the other hand will have to have to have resistors added or they'll blink very quick.
Senior Member
Joined: Sep 2012
Posts: 553
Likes: 0
From: Chesapeake Beach, MD
Year: 2001
Model: Cherokee
Engine: 4.0L Inline 6
CF Veteran
Joined: Jan 2012
Posts: 8,272
Likes: 1
From: Baltimore, MD
Year: 1999
Model: Cherokee
Engine: 4.0 I6 HO
Senior Member
Joined: Sep 2012
Posts: 553
Likes: 0
From: Chesapeake Beach, MD
Year: 2001
Model: Cherokee
Engine: 4.0L Inline 6




