Automechnic077
NAXJA Forum User
- Location
- Maryland
Good day folks,
Long time googler/ searcher newbie poster.
I have recently purchased a 99 Cherokee sport 4x4 4.0 it has 190k miles. I do have a snapon mt2500 scanner and the cartridges for Jeep. They may be of help if need be.
I am having a few issues which are leading me to believe the PCM may be bad. After googling and searching for months I thought I'd make a post as I'm not getting anywhere on my own.
Prior to changing the starter, and a driver's side hub assembly everything worked well on the Jeep including the A/C after a quick recharge.
My most important issue is with the blower control, ac/ heat. ( yes I have searched but got no reply) on previous threads. No matter the setting, fan speed hot or cold as soon as u turn the knob to ON the Jeep acts as if I cut off the ignition. Possibly 2 seconds the Jeep dies. The RPM gauge drops to zero fuel, temp, battery freeze where they are I believe. Driving, parked same effect. The Jeep will not restart with the blower running. The motor just turns over and over. In order for a restart I have to turn off blower. Cycle the key off then on the fuel pump runs and we fire right up. Parked or driving no difference in behavior. While parked I can turn on the blower and cycle the key the fuel pump never makes a sound. However It does prime with the blower off every time.
Now for the kicker. If i apply the brake all is well while parked. If I feather the brake pedal while driving just slight pressure to illuminate the brake lights heat, AC, all speeds of the blower work fine. The AC is even ice cold! It takes some skill driving with 2 feet. The person following behind me must think I'm nuts for riding the brake. the defrost is a must in rainy days and I gotta do what works! It's a weird topic to Google I found 1 thread where a PCM may have fied and another un answered so I'm looking for a bit of help in my own thread.
Thanks for this wonderful forum and looking forward to working with you guys and gals.
Long time googler/ searcher newbie poster.
I have recently purchased a 99 Cherokee sport 4x4 4.0 it has 190k miles. I do have a snapon mt2500 scanner and the cartridges for Jeep. They may be of help if need be.
I am having a few issues which are leading me to believe the PCM may be bad. After googling and searching for months I thought I'd make a post as I'm not getting anywhere on my own.
Prior to changing the starter, and a driver's side hub assembly everything worked well on the Jeep including the A/C after a quick recharge.
My most important issue is with the blower control, ac/ heat. ( yes I have searched but got no reply) on previous threads. No matter the setting, fan speed hot or cold as soon as u turn the knob to ON the Jeep acts as if I cut off the ignition. Possibly 2 seconds the Jeep dies. The RPM gauge drops to zero fuel, temp, battery freeze where they are I believe. Driving, parked same effect. The Jeep will not restart with the blower running. The motor just turns over and over. In order for a restart I have to turn off blower. Cycle the key off then on the fuel pump runs and we fire right up. Parked or driving no difference in behavior. While parked I can turn on the blower and cycle the key the fuel pump never makes a sound. However It does prime with the blower off every time.
Now for the kicker. If i apply the brake all is well while parked. If I feather the brake pedal while driving just slight pressure to illuminate the brake lights heat, AC, all speeds of the blower work fine. The AC is even ice cold! It takes some skill driving with 2 feet. The person following behind me must think I'm nuts for riding the brake. the defrost is a must in rainy days and I gotta do what works! It's a weird topic to Google I found 1 thread where a PCM may have fied and another un answered so I'm looking for a bit of help in my own thread.
Thanks for this wonderful forum and looking forward to working with you guys and gals.