Can anyone give me a comprehensive list of equipment on the 7.5 amp "ROOM" fuse?

I have a short that I have traced to it, and I have ruled out the dome light, the hatch light, and the keyhole light, but now I'm stuck, mostly since I don't know what else is uses it (I've heard the ECU is on it, but I don't know how to test it, where the ECU is, or even what the ECU is).

Telling me where and how to test these circuits would also be appreciated. I've tried the owner's manual and Haynes repair manuals, but got no help.

Thanks a lot!

Jim

 

On the room fuse:

warning/clock assembly
EC-AT (if you have a automatic)
ECU (pin#1A)
Radio
CPU (which in turn supplies the domelights and other interior lights.

That said. 90% of the time if the fuse keeps blowing its because of something related to an aftermarket or damaged OEM radio. Is there and aftermarket radio? or did the radio get stolen?

I bet there is or it did.

The other 10% of the time it is related to the CPU.

BTW: it is the Blue/Red wire

 

Icemark's list is a bit short

From the FSM:
- cargo light
- courtesy lights
- room and stop light (not sure, it's not the brake lights)
- warning buzzer/chime
- door lock and ignition key lights
- EGI/emission control system
- warning lights and clock
- alarm (if fitted)
- EC-AT control system (auto gearbox)

The radio is on a different fuse, so it's not that.

 

Actually I was looking at a 91.

I see in the series 4 wiring all the things you mention

 

That was all straight out of the S5 FSM. S4's have all that stuff too y'know...

 

I think I'm out of my depth, but still hopeful. I have no idea where to find some of these components or the wires that lead to them (or what they are, for that matter). If you could give me an idea of where to find the:
1. room and stop light,
2. warning buzzer/chime,
3. EGI/emission control system,
4. alarm (if this is not the same as the theft deterrent control system),
5.EC-AT control system (is this on automatics only?),
6. ECU,

I'd greatly appreciate it. BTW it's a manual transmission.

Also, and this is very important, will it hurt anything if I just pull the "ROOM" fuse, and drive without it, or if I pull it when I get to where I'm going so it won't drain the battery until I get back? Right now, the car's just sitting in the driveway with the battery disconnected so it won't drain.

 

No the radio's constant is from that fuse.

see where all the Lightblue/Red wires are going from the 7.5 amp room fuse



So again I go back to:

is there and aftermarket radio installed in the car or a problem with the existing stock radio

 

it is a stock radio; I did have problems years ago with the buttons not working well, and sent it out to an electrical shop, but other than that the radio works just fine.

I was trying to test the warning lights and clock, but ran into a snag in that the electrical bundle was so short, I couldn't really do anything with it. Is it supposed to be that short, or is there slack that I'm supposed to pull out. I didn't wan to pull too hard.......

Thanks,
Jim

 

Oops, my bad...

 

Actually just unplug it (the warning cluster) and see if you have the same draw, but unless there is a light or the clock is always on, even with the key off the cluster won't be your problem.

Try unplugging the radio as well, Its pretty easy to test most of the things there, just unplug them and see if the draw goes away. With the schematic I posted, just start running through unplugging things until you loose the draw.

But the ECU won't be the problem, it only uses that wire to retain memory, so you can rule that out already.

 

I think I'm getting there......

I unplugged the two electrical connectors and the two canon plugs (I think they're called canon plugs; they look similar to RCA jacks on a stereo... I also think they go the the antenna) on the radio and the draw dropped from greater than 150mA to about 10 mA. With the electrical connectors, but not the canon plugs attached the draw was about 70 mA. With just the canon plugs attached the draw was about 10mA.

So I guess I have two questions:
1. does this indicate a problem with the radio or the antenna? Can I at this point narrow it down to one or the other? and if not,
2. how can I check the antenna? I was looking around the antenna yesterday, and couldn't find the leads.... are they buried behind the interior wall?

Thanks for all your help...

Jim

 

anyone?

 

I hvaen't heard the term Cannon plug, so I am assuming you mean the antenna jacks

The draw would indicate something is always on in the radio. Replace the radio with either a know working one or new one.

Sorry it took so long to reply , I am out of town and reading this in my handheld

 

I'll do that as soon as I can.

Thanks so much for all your help. Couldn't have figured this much out without it.

Jim

 

That's funny, everything listed within box that starts with seat belt warning buzzer doesn't work on my car. Everything else under that room fuse works fine.

 

I don't have any spare radios lying around, and my wife's upset at me for wanting to pull the radio out of our other car to use it to check the RX-7.... so I figured it was important to know before I did so......

What's the likelihood the radios use the same electrical connector configuration? I mean, will one use 2 10 pin connectors, while the other uses one 20 pin connector? Or will the connectors be shaped differently?

Thanks

Jim