99 Cherokee HVAC Problem
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
I'll second that, thanks for letting us know how it turned out.
Jeff DeWitt
Howard wrote:
> Well since my lottery ticket yesterday was 0 for 7, thanks. Nothing
> like having been there for the answer. Thanks for posting the solution
> to your problem as many just fade away.
>
> JB wrote:
>
>>And the winner is.. Howard! Yup, battery acid on the vacuum lines. New
>>battery, new vacuum lines, new shocks. Rides great! Thanks!
>>Janie
>>
>>Howard wrote:
>>
>>>The older Jeep Cherokees (88-92) had a vacuum reservoir inside the
>>>right front bumper. Two vacuum lines went from there to the HVAC and
>>>other things like the speed control. The lines went under/behind the
>>>battery. Over time the line wore out (acid ate through) and the Jeep
>>>had both the HVAC and speed control problem. Look at the vacuum lines
>>>then see if there is still a vacuum reservoir.
>
>
Jeff DeWitt
Howard wrote:
> Well since my lottery ticket yesterday was 0 for 7, thanks. Nothing
> like having been there for the answer. Thanks for posting the solution
> to your problem as many just fade away.
>
> JB wrote:
>
>>And the winner is.. Howard! Yup, battery acid on the vacuum lines. New
>>battery, new vacuum lines, new shocks. Rides great! Thanks!
>>Janie
>>
>>Howard wrote:
>>
>>>The older Jeep Cherokees (88-92) had a vacuum reservoir inside the
>>>right front bumper. Two vacuum lines went from there to the HVAC and
>>>other things like the speed control. The lines went under/behind the
>>>battery. Over time the line wore out (acid ate through) and the Jeep
>>>had both the HVAC and speed control problem. Look at the vacuum lines
>>>then see if there is still a vacuum reservoir.
>
>
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
I'll second that, thanks for letting us know how it turned out.
Jeff DeWitt
Howard wrote:
> Well since my lottery ticket yesterday was 0 for 7, thanks. Nothing
> like having been there for the answer. Thanks for posting the solution
> to your problem as many just fade away.
>
> JB wrote:
>
>>And the winner is.. Howard! Yup, battery acid on the vacuum lines. New
>>battery, new vacuum lines, new shocks. Rides great! Thanks!
>>Janie
>>
>>Howard wrote:
>>
>>>The older Jeep Cherokees (88-92) had a vacuum reservoir inside the
>>>right front bumper. Two vacuum lines went from there to the HVAC and
>>>other things like the speed control. The lines went under/behind the
>>>battery. Over time the line wore out (acid ate through) and the Jeep
>>>had both the HVAC and speed control problem. Look at the vacuum lines
>>>then see if there is still a vacuum reservoir.
>
>
Jeff DeWitt
Howard wrote:
> Well since my lottery ticket yesterday was 0 for 7, thanks. Nothing
> like having been there for the answer. Thanks for posting the solution
> to your problem as many just fade away.
>
> JB wrote:
>
>>And the winner is.. Howard! Yup, battery acid on the vacuum lines. New
>>battery, new vacuum lines, new shocks. Rides great! Thanks!
>>Janie
>>
>>Howard wrote:
>>
>>>The older Jeep Cherokees (88-92) had a vacuum reservoir inside the
>>>right front bumper. Two vacuum lines went from there to the HVAC and
>>>other things like the speed control. The lines went under/behind the
>>>battery. Over time the line wore out (acid ate through) and the Jeep
>>>had both the HVAC and speed control problem. Look at the vacuum lines
>>>then see if there is still a vacuum reservoir.
>
>
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
I'll second that, thanks for letting us know how it turned out.
Jeff DeWitt
Howard wrote:
> Well since my lottery ticket yesterday was 0 for 7, thanks. Nothing
> like having been there for the answer. Thanks for posting the solution
> to your problem as many just fade away.
>
> JB wrote:
>
>>And the winner is.. Howard! Yup, battery acid on the vacuum lines. New
>>battery, new vacuum lines, new shocks. Rides great! Thanks!
>>Janie
>>
>>Howard wrote:
>>
>>>The older Jeep Cherokees (88-92) had a vacuum reservoir inside the
>>>right front bumper. Two vacuum lines went from there to the HVAC and
>>>other things like the speed control. The lines went under/behind the
>>>battery. Over time the line wore out (acid ate through) and the Jeep
>>>had both the HVAC and speed control problem. Look at the vacuum lines
>>>then see if there is still a vacuum reservoir.
>
>
Jeff DeWitt
Howard wrote:
> Well since my lottery ticket yesterday was 0 for 7, thanks. Nothing
> like having been there for the answer. Thanks for posting the solution
> to your problem as many just fade away.
>
> JB wrote:
>
>>And the winner is.. Howard! Yup, battery acid on the vacuum lines. New
>>battery, new vacuum lines, new shocks. Rides great! Thanks!
>>Janie
>>
>>Howard wrote:
>>
>>>The older Jeep Cherokees (88-92) had a vacuum reservoir inside the
>>>right front bumper. Two vacuum lines went from there to the HVAC and
>>>other things like the speed control. The lines went under/behind the
>>>battery. Over time the line wore out (acid ate through) and the Jeep
>>>had both the HVAC and speed control problem. Look at the vacuum lines
>>>then see if there is still a vacuum reservoir.
>
>
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
check the vac supply line on the engine for the hvac esp. if u have the 4.0
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
check the vac supply line on the engine for the hvac esp. if u have the 4.0
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
check the vac supply line on the engine for the hvac esp. if u have the 4.0
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
Guest
Posts: n/a
Re: 99 Cherokee HVAC Problem
check the vac supply line on the engine for the hvac esp. if u have the 4.0
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
engine
JB wrote:
> A recent 300 mile camping trip pulling a small tent trailer afforded an
> opportunity to better characterize the problems with the HVAC of our
> 1999 Jeep Cherokee. We'd taken it in the week before our trip with a
> complaint that the ventilation would randomly shut off the vents
> although the fan continued to run. Our repair shop found a technical
> service bulletin that was relevant, diagnosed a failing panel vacuum
> actuator, and replaced the unit.
>
> However, on our trip we had the same problem but now were able to
> observe that the ventilation shuts down under conditions of high
> manifold pressure (e.g., going up hill) but the ventilation was
> restored on level or downhill grades. Rapid acceleration on level
> ground also caused the ventilation to shutdown.
>
> This behavior was consistent regardless of whether the air conditioner
> was selected or just simple fresh air ventilation. We did not check
> whether it occurred when the selector was positioned for defrost.
>
> A possibly related problem is occurring with the "factory installed"
> cruise control. It used to be quite solid, keeping the speed within ±
> one mph--now it has a good five to ten mph slop and can take tens of
> seconds to resume the set speed.
>
> Fuel consumption has remained constant, we continue to get 20 mpg,
> in-town and on the highway with or without the trailer. I have noticed
> that the engine seems to have some hesitation and not quite the same
> acceleration lately but it is approaching 90,000 and is time for
> service.
>
> Any help would be appreciated.
>
> Janie
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