Some of you might have seen my thread about how I just bought a Jimmy. Well I don't know anything about electrical systems or fuses and I need some help. It's a 94 Jimmy 4 door.
When I got the car I noticed that none of the inside lights or the horn worked. The gauges work fine but the dome light, and all mirror lights, etc don't work at all. Also, the voltmeter constantly reads up at 19 when the truck is running. I checked the battery and it's charging at 14, so I'm thinking maybe the gauge is broken but I'm not sure. The alternator is recent so I don't think that's a problem. I checked the fuses and found that the horn fuse was bad. After putting in a new one the horn and the lights on the rear view mirror worked but none of the other ones did. I gave up on the issue because I had to drive up to school. On the drive there, I was on the highway and went over a bump and the rear view mirror lights turned on by themselves and wouldn't turn off again. I had to pull the horn fuse to get them to turn off because I didn't know what else to do. How do I fix this?
In the fuse panel there is a spot that says "ACC Lights" but there is no fuse in it. Could this be why the dome light and other lights don't work? I tried to put a fuse in it to see if that was the case, but for some reason it won't go into the socket even though it looks to be the same as all the other sockets. If it makes a difference I have the overhead console. I'm so confused at this point.

 

You're right. Your lights work off of the Horn/DM fuse (20 amp). Couple of questions though.
1) Does your cig lighter work? It taps the same fuse.
2) Do the lights come on with your dimmer switch all the way to the right? (You'll feel the detent to turn on the lights)
3) Do the lights work if you open certain doors but won't work when others are opened?
4) Have you pulled the individual bulbs and checked for power at the sockets and if the bulb has continuity through it?
5) Do you have lighted vanity mirrors?
I think you're going to find at least 1 bad door jamb switch. My driver's door switch was bad and wouldn't turn on the lights while the passenger side lit them up just fine. This actually completes the circuit and grounds the power wire through the lights.
Be more than happy to help you out but need a little more info. I have a factory wiring diagram for this year and the interior lights schematic is 3 pages long.

 

Check that someone hasnt done something stupid like jam a paperclip peice in that fuse slot you cant get a fuse into, you can find the amperage fuse you need is usually labeled on the fuseboard or cover in brackets like this ACC[10A] or HORN [30A]. If you have a multimeter you can easily check the door switches for voltage changes when you push the pins in by hand. The test light will show you if there is power to the bulb sockets. Once you get the hang of using those tools, you will be troubleshooting electrical probs in no time. I would rather troubleshoot electrical than mechanical anyday, its much cleaner, and if you are making money doing it, its easy money. I would rather do electrical repairs for 4 hours than take apart brakes and front ends that make you filthy.

Some cheap things you might want to pick up a the discount tools store in your area are:

A fuse tester - you can usually get these with a bunch of bulk fuses for about 10 bucks.

A multimeter - cheap ones work just as good as expensive ones and cost about 30-40 bucks. As long as it has 12V and AMP settings, its all you will need for car work. We can help teach you how to use it.

A 12V test light - These can be as cheap as a couple bucks.

In canada we have stores called PRINCESS AUTO that have almost anything you can need at a fraction of the price of name brand tools. They work well, but for wrenches and sockets that you are going to use more than once in a blue moon, you are better to get Sears Craftsman, or Canadian Tire Mastercraft brands. They have lifetime exchange with no receipt on hand tools and are excellent quality.

 

Thanks for trying to help Gimpy. To answer your questions:
1.The cigarette lighter up near the radio doesn't work but the one near the floor at the end of the console does.
2.No lights come on with the dimmer switch all the way to the right, except for the lights on the rear view mirror (but that was when it was functioning properly and wasn't always on)
3.No lights come on when I open any of the doors except for the rear view mirror lights which I can't check to see if it's only certain doors now because they won't shut off with the fuse in.
4. I haven't pulled individual bulbs yet, but I will do that.
5. Yes, I do have lighted vanity mirrors. When the fuse is plugged in, the passenger side works but the drivers side does not.

So basically, the only lights that work inside the car are the gauge cluster lights, the rear view mirror lights (even though they are stuck on), and the passenger side vanity lights. The horn does work with the new fuse.
That leaves the drivers side vanity light, the dome light, 2 small round lights in the front of the overhead console, and the light in the back near the hatch that don't work, plus the cigarette lighter near the radio.
When I first plugged a new fuse in the horn socket I'm pretty sure all of the doors would switch on the rear view mirror lights and then they would turn back off again after a good couple seconds. I noticed that the drivers door switch is kinda loose and jiggly and when you try to tighten the little bolt on it it won't really do anything.
Thanks for any help you can give!


And Ohsofly,
I will look into getting at least one of those tools but I'm going to have some difficulty because I'm up at school in like, pretty much the middle of nowhere. No one jammed anything into the slot but does anybody know if there's supposed to be a fuse in the acc light slot?

 

Eff10, your best buy is going to be the multimeter then. Walmart, crappy tire, NAPA, autozone, they should all sell cheap ones.

Ill go out to my blazer on stands and check my fuses and see what I can find out about that ACC slot...

I have the same kind of lighting problems in my interior too, only the lower cig lighter works.

 

I'll get one of those then. Thanks for checking for me. Maybe as we figure out my problem we can fix yours too.

 

O.K. my ACC/LPS slot has a 5A fuse in it, it is labeled below to slot to have a 5A in it, its about the 3rd from the left and about 5 up from the bottom.

That multimeter will also come in handy in your house too since you can set it from 12V all the way up to 1000V... I spent about 40 bucks on mine, and its come in handy many many many times. Mostly for troubleshooting car stereo stuff, and testing alternators and batteries. spend the extra couple bucks for the digital multimeter, I forgot to add that, its more precese than the one with the needle that rotates.

Its an easy way to make an extra 40 bucks an hour troubleshooting stereo stuff since it can test for continuity too, great for finding pinched speaker wires from an installer that didnt route them properly. I do this kind of work on the side at my house, I love it.

 

I solved one of the problems. The mirror lights wouldn't turn off because the door switch was loose and crooked. I now still have the problem with none of the other interior lights working, and if "acc lights" is important for the functioning of the rest of my lights, I need to figure out why no fuse will fit in it.

 

Sorry I haven't got back sooner. I'm working on it now though. Will keep you posted. I don't see anywhere in the wiring diagran where the ACC fuse ties into the interior lights. The only one that appears to operate the lights is the HORN/DM fuse. Did you say you fixed the door jamb switch problem? You have 4. Which one was loose? I had to replace mine as it just wouldn't make good ground contact. Probably need to see of you're actually getting power to the sockets. I also would pull the wire off the upper cig lighter. Sometimes they short especially of there's some conract between hot and ground inside. It won't be apparent without really looking at the inside of the lighter. It goes together just so. I know from the hard way. You can pull your ashtray and there is a screw on the left lower side and a couple that you can see when you open the glove box to get the panel off. The upper left corner of the panel has a plastic stud that goes into a guide hole. No fastener here. Then you can just disconnect the lighter wire (1 Orange and 1 Black) and see if you blow the fuse. I had a lighter that was loose and it drove me nuts until I figured out what was wrong. Had it apart like 4 times.

 

The drivers side front door had the loose switch. I didn't actually fix the problem yet but when I held the switch in the light turned off after the set number of seconds. When I went out to my car later on though the light was on again. I'm hoping it's just loose because that would be so much easier. I will try to check the cigarette lighter like you said. I'm sure it won't be hard because the whole radio/ashtray box thing is loose and jiggles around while I'm driving which gets really annoying. I'm think it's missing some screws somewhere. Will this help to solve why my lights don't work or is this separate? As long as I have one cigarette lighter working I'm more concerned about having the lights. I'm sure you understand how frustrating it is to try to get into the car at night when you can't see a thing.
I don't know if this is related but my blower works in low and medium but not on high, and it squeaks a lot when it's on. Thanks for your help.