Crazy Electrical Problem

[xzalt]

Recently a problem has come up where whenver anything is plugged into my cig. lighter it shuts my radio off, and whatever is plugged into the lighter socket doesn't work either. I've checked the fuse for the lighter socket and nothing is blown, any ideas to what this could be?

I'd appreciate any and all help on the subject.

 

[Matthew Currie]

Look for a bad ground wire. Even if you can't find one, try adding a new ground to the cigarette lighter.

 

[xzalt]

thanks for your suggestion but I don't think its the ground. By testing various combonations of leads together I've determined that it is the puple wire with a white stripe that is the faulty connection. My head unit also is powered by the same purple wire with a white strip. I guess my question would be why these two are having problems, especially when none existed before. I can't get to where the wires connect and I haven't been able to find a wiring diagram that details the wire(s) in question. If you could provide any insight to this issue I'd appreciate it.

I'd like to keep to keep the lighter socket turning on and off with the ignition switch, but I'm willing to change that if necessary.

thanks

 

[langer1]

They come from the fuse block.
What the year and all that good stuff?

 

[xzalt]

its a 95 4.0 auto.

the part I can't figure out is why the lighter socket doesn't work at all, or the inverse, why my head unit does work, but when something is plugged into the socket it turns off the head unit. Especially since it doesn't blow a fuse or anything.

 

[langer1]

Where is your head unit grounded? If it's grounded to the lighter socket and it only good enough to run the head but not good enough for something pulling more amps that would explain it. It would not be a short so would not blow a fuse.

 

[xzalt]

its grounded to the ground wire that comes out of the stock wiring loom. The part that is crazy is that setup has worked for 4 years with no problems, and then last week they stopped working together.

 

[langer1]

Ok then, one thing the lighter and radio have in common it they get power from a section on the ignition switch


. Part of the fuse box goes to the Batt+ but one section is powered by the ignition switch.

 

[Matthew Currie]

Perhaps I didn't make things clear enough in my first post. If the radio and the cigarette lighter share a common hot lead, and that hot lead is connected properly to both, and the radio has a ground, and the cigarette lighter doesn't work, I think what is happening is that the lack or failure of the cigarette lighter's ground is causing it to seek ground through the radio. I suggest that as a first step, you replace or add a dedicated ground to the cigarette lighter and see if this solves the problem.

If one circuit which shares a hot line loses its ground, it will follow the common connection through whatever other component has a ground. This kind of problem is pretty typical of a failed ground.

edit: I should add that one characteristic of this failure is that the wrong connection is drawing its current through the other component, which is not a good thing, and probably explains why the head unit is shutting off.

 

[langer1]

Perhaps I didn't make things clear enough in my first post. If the radio and the cigarette lighter share a common hot lead, and that hot lead is connected properly to both, and the radio has a ground, and the cigarette lighter doesn't work, I think what is happening is that the lack or failure of the cigarette lighter's ground is causing it to seek ground through the radio. I suggest that as a first step, you replace or add a dedicated ground to the cigarette lighter and see if this solves the problem.

If one circuit which shares a hot line loses its ground, it will follow the common connection through whatever other component has a ground. This kind of problem is pretty typical of a failed ground.

edit: I should add that one characteristic of this failure is that the wrong connection is drawing its current through the other component, which is not a good thing, and probably explains why the head unit is shutting off.

The reason I suggested the accessory section of the ignition switch was because MORE than the radio and lighter share the same ground. But only devices powered by Accessory section are effected.

Ether way it’s one or the other, bad ground or bad ignition switch or power relay if there is one.

 

[xzalt]

thanks for all your help and suggestions. Perhaps I don't quite understand, but I don't think it can be the ground because if I connect the lighter to the ground for my radio or its supplied ground with the original power source, it doesn't work, but maintaining the original ground for the lighter with a hot lead from the battery does allow the lighter to work.

As an added bonus it appears that my radio stays on longer now after I turn off the ignition. It probably stays on an additonal 2-3 secs after I turn the jeep off. It didn't do this before. I don't know if that information helps or just adds a new twist to the information. thanks

 

[langer1]

Ok then, one thing the lighter and radio have in common it they get power from a section on the ignition switch so it's going bad.

 

[xzalt]

thanks for helping me track down the problem. Do you know if the switch is repairable or just needs to be replaced?

 

[langer1]

It's cheap and easy, it's under the dash mounted to the outside of the steering tube, they cost less that 20 bucks, make sure it's pluged in tight also.

 

[xzalt]

I assume this part can be easily sourced from an autozone or other automotive parts dealer?

 

[langer1]

I assume this part can be easily sourced from an autozone or other automotive parts dealer?

Sure can, did you check to see if it's tight?

 

[xzalt]

I'll check to make sure its tight first. Just to be clear, its not located near the lock cylinder, but under the dash?

Is there a color module I should be looking for, or any other distinguisting features?