QuestionI have a 94 Chrysler LHS that the battery keeps dying on me. I've replaced the battery,alternator,and all the leads to it but found no change. What really confuses me is that I can jump the car and drive it, but once I turn it off it wont start again. Please help me!
AnswerHi Chris,
You probably have some sort of a short circuit or component that is drawing current way beyond what it should or when it shouldn't at all. You need to read the current draw on the battery and then start pulling fuses ones at a time from the underhood power distribution center to see which one(s) cause a significant reduction in the current draw when everything is turned off.
The best way to find what is causing the draining is to obtain a volt-ohm meter at an electronics store or an auto parts store, or borrow one from a friend. (You can for a little more money use a meter that also measures current, amps, and use it the same way as I will now describe except you will be trying to find fuses that when removed reduce the reading (less current flow) on the dial). You should be able to get one for under $20. Then you disconnect the clamp from the "-" or "neg" post of the battery, then remove the "+" or "pos" clamp. Then put the two test leads of the meter on the two clamps (one lead on each clamp) with the meter set to read ohms. It should read something less than infinite, but you would like it to read more that 100 ohms and ideally much more ohms than that, which would mean there was no source draining away the charge. If instead you find that it reads only 5 or 10 ohms that means there is a component that is draining the battery. (If you intend to measure current, then the battery needs to be in play so you would just remove one battery clamp (the - post one) and insert the leads of the amp meter between the clamp and post that you have disconnected the clamp from).
The procedure to find out the drain source is to disconnect each of the fuses (start with the larger fuses in the power distribution center box under the hood, it is long and thin and located behind the battery) that are assigned to a specific circuit in the car, one at a time, and see if the meter reading moves toward infinity (ohms) or decreases (amps) as the result. If there is no change in the reading of the meter, then replace the fuse and move to the next one in the distribution center box and see if it causes an increased reading, etc. When you find one (or more) such fuses that when removed caused the reading of the meter to go up significantly, then look for the label on the fuse box for that fuse, put the fuse back so that the reading decreases again.
Then if the fuse isn't labelled as to its purpose write me back and I can tell you which fuses/circuits the fuse in the distribution center powers up in the secondary fuse box that is under the dash. Then you will go to the under dash box and do the same thing, and when you find the smaller fuse that also raises the resistance (decrease the current) when pulled you will begin to unplug each of the electrical items that are powered by that fuse and keep checking until you find the item that causes the reading to go up again. That is the faulty component that is causing your problem.
You will want to do these tests with all the doors closed so that no lights are "on" and the car is sitting just as it is when you have it shut down. Be careful not to change anything about the car doors/lights (always close the doors before reading the meter) while you are doing this testing or none of it will make any sense.
This is something you can do yourself and save labor costs by so doing. If you find a fuse that when removed causes the reading to rise significantly, tell me what the number of that fuse is and I will tell you what to do then to solve that problem specifically (how to unplug the suspected faulty item).
Whenever you go to reconnect the battery, always put the + post clamp back on first, then put on the - post clamp. The reverse is true when you disconnect the battery (as I described to you at the start). It is done that way for safety so you don't accidentally short the battery and get a burn.
So let me know what fuse #'s in the power distribution center are causing signicant changes in the meter reading and if you can find an associated fuse under the dash that does the same thing let me know that too. You can get back to me via the "thank and rate" tab at the bottom of this message if I am listed as being 'maxed out'."
Once we find the cause of the drain and fix that I suspect the other issues will resolve themselves. The wiring diagrams total to 150 pages, so let us work together on this. I would like to communicate back and forth thru the allexpert site, not by email so that we develop a record that might help others in the future who read the archives of previously answered questions. So use the "thank and rate" approach to communicate back if I am shown as maxed out and I will get back to you promptly.
Roland
