QuestionQUESTION: Hi Roland, my 1999 Jeep cherokee sport 4.0L has to be jump started at least once a day. The engine attempts to turn, but sounds very drained, then it just clicks. The interior lights come on, but dim, the radio comes on, the windows will go up and down, but very slowly. The battery, oil and temp gauze do not register when I turn the key switch to on position, but show normal setting and battery fully charged immediately after jumpping my car off. The exterior lights come on and dim when I am trying to start the car. The battery is two years old, shows an OK charge, the mechanic said not low enough to warrant a new battery, but would probably start there in the process of elimanation. I would just like to know what other possibilities it could be or most likely is before replacing other things. The mechanic said, charging system is okay, alternator belt is okay, battery-ok charge, a little smaller battery than factory, but should be okay. Any suggestions? I just repalced the computer in September.
Merry Christmas,
Theresa
ANSWER: Hi Theresa,
The first thing to do is to measure the amount of current (milli-amps) that are flowing out of the battery when the vehicle is off. If you can buy a volt-ohm-milliamp meter you could remove the - post battery wire's clamp and put the leads across the gap so-created. Turn the meter to milliamps and see if it is in the range of 25-50 or not. If not, then there is something that is 'on' that shouldn't be. It could be a trunk, underhood, or glove box light for example or it could be a component that shouldn't draw that much, or a short circuit but at least you would know if that 'ignition off draw' reading was proper or not. Then you can try to find out why, or if that is OK, then you are probably back to the battery/charging system not being up to snuff.
Roland
PS Thank you so much for the kind remarks and blessings. I thought of suggesting that you might review the vehicle to notice whether there are any add-on units that may be drawing current without your knowing about it. Anything in the audio/digital device/convenience item that could be 'on' even though the key is removed? It might be something plugged into the cigar lighter socket for example.
Best wishes to you for a wonderful Christmas and New Year.
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QUESTION: Thank you. I did think of that and the only thing falling into that category would be my GPS. I haven't seen any change since unplugging it. I might mention something that has been totally unexplainable, but worked, so I have left it alone. In Aug/Sept while attempting to get my check engine light to go away after replacing the computer,I was checking the fuse under the dash and accidently placed a fuse into what was deemed an "open" space. When I did that, my AC which had stopped blowing cold, started working again. If I remove the fuse, it still blows, just doesn't get cold.
ANSWER: Hi Theresa,
Unfortunately I don't have a wiring diagram for your vehicle ant that limits my ability to help out. But I do believe that the measurement of the current flowing through the battery when the ignition switch is off is the first step to determining why the battery is not staying charged. It could be though that if you do only short driving trips that you don't really get the battery fully charged up. But that would not normally be an explanation.
Something like the GPS could have started you down this pathway to having a nearly discharged battery, but if that was disconnected some time ago then it would be hard to blame it now.
The battery could be faulty and that can also be tested. The fuse/a.c. discovery may simply be the re-installation of a necessary fuse that activates the a.c. compressor clutch which it the principal device that is required to get cooling from the system. I sould hope that either measuring the ignition off draw yourself or the mechanic doing that would help sort out the cause. In the meantime, if you have or can buy a battery charger and you have the vehicle parked near a wall socket then you could charge the battery overnight and see if that helps to keep you going during the day, or not. If not, then I would suspect an issue with the battery.
Roland
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QUESTION: Hi Roland, the battery did need replacing. Seems to be running fine now, although my heater has decided to blow cold instead of warm....but I will save that battle for another day. Have a wonderful New Year!
Theresa
AnswerThanks for the update and good news, Theresa. On the heater, after you have driven far enough to warm the system open the hood and touch each of the two heater hoses that pass from the engine compartment through the firewall to the cabin. They are side-by-side and should be similarly warm. If one is quite cool then that would suggest that the coolant flow through the radiator core is impeded. Removing the hoses at the firewall and backflushing the heater core would possibly improve that situation.
If both hoses are similarly warm, then it is probably due to a problem with the 'blend-air door' of the HVAC unit under the dash. That door controls the mix of heated air and cool air to give the desired air temp in the cabin. I don't have the manual for a '99 model but it could either be controlled mechanically by a lever and cable or it could be controlled electically by a knob/wire/electical door actuator. So notice what the temp control device is like and that would give you an idea. I do have the '06 manual but I would not be certain it applies to your '99.
I hope you can sort this out so that you have a Warm New Year!
Roland
