Expert: Rob Painter - 2/26/2011

Question
QUESTION: I have a 92 Fleetwood with a 4.9L engine. For the longest i have had an electrical problem with it. It keeps draining the battery like every two days if i leave it hooked up. I have replaced the battery, alternator, fuses and have had them checked since. Do you have any suggestions of where would be a good place to start looking for a short in the electrical system?

ANSWER: Hello,

To find the problem is easy. Get a test light. They don't cost much and all parts stores have them.

Remove the positive battery cable. Install the test light between the cable and battery post. The test light will be on if you have a draw. Remove the dome light fuse and see if test light goes out. If not, remove the courtesy light fuse. Again see if the test light goes out. If the light is still on, one by one pull the fuses checking if the light goes out. If not reinstall that fuse and remove and replace until the test light goes out.

You are trying to find the circuit draw. Once you find the circuit, then you need to disconnect items on the circuit and when you find the problem, you are set.

Let's say the test light goes out when you pull the dome light fuse-that's the circuit. Since I know that the cigarette lighters are on that circuit, I would disconnect the lighters. Then I would put the fuse back in and close the door. If the test light is off, I found a bad lighter which was causing the problem. Then you either leave the lighter unplugged or replace.

Good Luck!


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---------- FOLLOW-UP ----------

QUESTION: I have followed all the things you advised me to do and the test light never went off so do you have anymore suggestions that i should try?

Answer
Hello,

Many Cadillacs have more than oe fuse boxes and you need to look at your owner's manual.

If no other fuse box exists, then it gets to be a nightmare to find. A bad alternator could be the draw, starter solenoid or something else. The problem with that is that they are hooked to power so, unless an internal part can be found bad, you are left guessing. Make sure door is not open with dome working. Make sure under hood light is not on. Hood light can be disconnected at harness. Many under hood lights require key on and if it is on and I forgot to tell you, I apologize.