Mechanically Declined

For the last 2 weeks I have been struggling with my 98 xj dying in the parking lot at work. Goes totally dead of power. I jump it, take it in, everything tests fine, they replace a relay going from a pair of aftermarket fog lights that wasn't reading right give it a clean bill of health. I have a new Battery and the alternator is testing good.

Bam, happens again next day.

I take it in, they have it over the weekend to test everything. $325 later they give it another clean bill of health after replacing some wiring from the fog light and putting a new switch it because apparently it was done all wrong (had a friend do it). Apparently there were fuses blown as well. I was pretty tore up that a pair of fog lights could cost this much money.

Today, I go to start it assuming this nightmare is finally over and BY GOD the battery is out of juice.

Why didn't happen in my driveway over night? Why isn't it happening when they left it in the shop? Only when I take my 5-10 minute drive to work and after 4 hours of sitting in the sun today? Maybe the warm whether has something to do with it.

I am beyond defeated with this and have been left stranded too many times already. The mechanic can't seem to figure it out. Any help or advice would be huge for me.

Tbone289

What you need to do is put an ammeter on the system and check for a parasitic drain. If you have a DMM, hook it in series between a battery lead and the battery, and read the current in amperes. Measure with the Jeep shut off. If there is a current drain, start pulling circuit fuses until you find the one that drops the current drain. The culprit will be found on that fuse's circuit.

I can't really explain why this is happening in one place and not another though... It should only be time-sensitive, not location sensitive.

Mechanically Declined

The timing is strange. It will sit all through the night and be fine to start up and go to work at 8am. But when I come out to the car at 12pm, its dead. I even got a jump when home to eat and turned it off for 20 minutes and it was dead again. The shop thought it was fine because it wasn't draining over the weekend. Has to be a wacky ground right?

Tbone289

It has to be an intermittent drain of some sort. Disconnecting and cleaning all grounds would be a great idea at this point.

Suprmn

I would verify the voltage at the battery several times. When you get home, first thing in the morning, when you get to work, when you go out and it wont start. Try to get a pattern of what is going on. It kind of sounds like a relay sticking. Make sure your glove box light is going out when you close the glove box. Make sure your dome lights are going out when you close the doors. There are youtube videos that show how to test for a battery drain. Check those out and try to find a pattern to what is happening.

Mechanically Declined

Well I took it back to the shop and it appears to be back to starting after they replaced a faulty wire or two running to the starter.

I am still suspicious as I was sure it was a drain. Could this be an actuator? Maybe a bad one could have fried that wire?

Side Note: Previous owner had pulled all of the courtesy lights because they stay on nonstop even when car is off. I have been driving it like that for about a year. That could be a bad door switch. It's strange to me and I just don't want to get stranded again from another misdiagnosis.