On advice from this forum (thanks to all who helped), I bought an ammeter to find out what was draining the battery so quickly (battery goes dead in less than 2 days), and I believe isolated it to the 7.5 A fuse labelled "ROOM".

I think it's this fuse since without it installed I measured a draw of about 25mA, but with it installed the ammeter pegged out at better than 150 mA.

Can someone please tell me if my conclusions are reasonable and logical, or am I totally off base?

Also, what does the "ROOM" fuse do, and how do I now go about fixing it so it no longer drains my battery?

thanks,

Jim

 

Sounds like you have a light on somewhere. Check the hatch/trunk light. That's the most common one stuck on.

The room fuse supplies power to the dome light circuit (through the CPU) and clock/idiot lights as well as the ECU and radio (and tranny EC if you have an automatic).

So again I would first check the dome lights and truck lights, then the radio wiring (if the radio is aftermarket or has been worked on recently), then the other things.

But I doubt its any of the ECU/AT-EC/idiot lights.

 

Thanks for getting back to me so quickly.....

Please let me know if my conclusions are logical and probably correct. (I also just reinserted the fuse, and got a little spark, which reinforces my conclusion that there's a short here somewhere.)

I checked the dome/trunk lights/storage compartment lights, and they aren't on. Power couldn't be flowing without them being on, could it? Obviously, the clock will be drawing power, but not that much, right? Also what's the ECU and how do I check it? I haven't done anything to the radio in years, and it's factory original.

It sounds like there's nothing on the ROOM fuse that I can't live without, so I can just drive the car without the fuse installed, right?

Thanks,

Jim

 

If you are checking the voltage from inside the car then having the door open will change the draw due to the door and dome lights being on. The lil light above the key hole on the steering column is also enough to create a draw so make sure all of these light are off before you try testing things.

 

well 150Ma is about a small 5 or 10 watt bulb, or a relay on. The computers should not draw that much (they are only about 5 to 10 Ma each).

Is it still a stock stereo and power antenna?

How about the CPU, does all the things like the door buzzer, light buzzer, horn, work while the fuse is in?

 

There is a light in the glove box too!

Your problem seems very familiar to one I had a while ago. After I rewired almost the entire car; I found out I had a bad battery. Take it to an autoparts store and have them check it. It takes about an hour so bring a friend. Or you can just sit the battery on the ground with no wires hooked up to it and attach you volt meter to it and see what it reads. Then come back - let's say - 4 hours later and see if it still reads the same. Mine was draining itself over the course of a few days. Once the plates in the battery warp far enough, they will touch each other and start to drain the battery. How many times has your battery been drained? If it is more than 7-8 times you may need to replace it.

 

I closed the door while testing, so the door and dome lights shouldn't be a factor. Haven't checked the light above the key hole (didn't know I had one.... maybe it didn't come with my trim package). It shouldn't be the battery, since it's been replaced twice in the last two years, and the last one's been in less than 2 months (took it to a shop where the diagnosis was "bad battery", so they replaced it and the car's still draining the new one in less than 2 days). I'll check the light in the glove box.

Haven't checked all the bells and whistles with the fuse in yet (didn't know what the fuse did until you explained it to me), and it is still a stock radio and power antenna.

BTW it's not necessarily 150 mA, that's just the upper limit on my ammeter. The needle pegs out on the high side, so it could be more; I don't have any way of checking without getting an ammeter with greater range.

Thanks again,

Jim

 

well normal draw on the car should be around 60mA.

The glove box light comes on only with the parking lights or ignition depending on what year.

GXL, LX, the 88 GTU and all the T2 will have the door keyhole light.

Might be easier to unplug the CPU in the drivers kick panel and see it would be the door light