electrical nightmare

[boodlebutt]

lastnight my gf came back from the store telling me that some guy almost hit her at a red light . All because the idiot was watching HER brake lights instead of the red light at the intersection.
ok. yes i admit that not having break-lights is dangerous. which brings me to my problem. for you that have the np242 t-case (2wd, fulltime 4wd, part time 4wd & 4 lo). the light on the dash keeps flashing "full time" 4wd. not a real problem here (probably a goffy wire). but when it flashes "part time" 4wd, the break lights don't work ... which can be very bad.
if any of you have had to deal with this any insight would be helpful.
i checked all the fuses, both lights & even called the local autozone for the fuses under the hood (which by the way they can't get ). so i'm thinking that there is at least one frayed wire somewhere touching to ground. but i'm just fretting about tearing the interior apart to find the stupid thing!!! and then not finding it.

any insight on this PITA problem of mine would be greatly appriciated!!!
thank you in advance & keep the jeep muddy!!
'cuz a dirty jeep is a happy jeep! lol

[airforce26yrs]

It definately sounds like you have some shorted wires somewhere. I do not think it is a fuse problem, if the brake lights work sometimes.

I have a grand with the 242 but my dash light does not flash, it stays on steady for whatever position I am in.

Sorry I can't be of more help, but don't know where to tell you to start looking.

[andy02]

It really does sound like you have a frayed wire somewhere. I would start easier first though. Check all your grounds. If your taillights are like most Jeeps, they are grounded through the screws. Make sure that the screws holding your taillights on are not corroded. If the grounds don't fix it, I would then start chasing wires. Start with a wiring diagram and a multi-meter. It sounds like your problem is intermittent which is going to make it harder to trace. If you can get some help from your friends, have them shake wires while you shoot them with the meter. At least that way, you can chase it down to a smaller area rather than stripping the entire interior.

[boodlebutt]

thanks, thats what i was thinking too. but gettin a "friend" out there to help is almost imposable. haven't lived out here for very long & don't realy know anyone yet.

well, thanks for the insite. gonna have to do it so that it's done & finished.

[bigrubbers4x4]

butt, if your looking for a friend in butler, one of my club member just moved there not to long ago. when he comes home, he is usually helping me wrench on my junk. PM me and i will give you his number so you guys can hook up, i am sure he will help you find that gremlin.

[devildog4x4]

... the light on the dash keeps flashing "full time" 4wd. not a real problem here (probably a goffy wire). but when it flashes "part time" 4wd, the break lights don't work ... ... i'm thinking that there is at least one frayed wire somewhere touching to ground. but i'm just fretting about tearing the interior apart to find the stupid thing!!! and then not finding it.

Just some suggestions for you. Let me start off saying that I currently do not have your set up (sounds similar to my 86 Cherokee I used to have) nor am I familiar with the wiring of your system. My suggestion/guess is based on 15 yrs aircraft electrical and electronics experience and 25 yrs fixing vehicles because I couldn't afford to pay someone else.

If u have a wire diagram - see if there are any common wires for brake lights and your 4wd indicator system. If there are - look at these wires first. I don't think they would have any common wires but who knows. You don't say what yr/model you have but if you have a newer vehicle that requires you to have the brakes on in order to start it - it might be in that loop.

It sounds like you might have crossover issues. This is where the insulation on wires are degraded or worn/damaged and the path of electricity crosses over into another circuit. Commonly referred to as a short but it is not, a short is when a live wire touches ground directly. When this happens you will blow a fuse. If you are not blowing fuses then wires are touching/crossing paths.

Electricity will take the path of least resistance and your dash indicator lights are smaller loads than your brake lights. That is why I would look at wires from your brake switch and in the harness routed to your transfer case or what ever controls your "part time 4wd" circuit. Your brake light switch is located somewhere under the dash near your brake pedal arm -when you push down on your brake pedal a switch is physically moved sending power to your brake lights.

Basically - if your brake lights do work when your "4wd indicator" is not on, your circuit is good to the back of the vehicle. It has to be up front.

Have you done anything to the vehicle like screwing anything to the floor boards or any where else. If you did - your screw may have hit some wires.
If you want - send me a PM and I will give you my cell ph# and you can call me and I can try to help you out over the phone when you decide to work on it. Good luck. Oh - just an FYI, I think threads like these are suppose to be posted in the Tech Help forum. Jeep On!

[boodlebutt]

well it's a 1989 cherokee limited. all stock. haven't done anything to the floorboard area yet (at least not near any wires) did a little "bubble gum" fix to the rocker panels last year, but no wires near those (i checked before doing it).
as for the indicator lights flashing & killing the brake lights, i know that it's the wires insulation frayed off somewhere. we keep it in 2wd (unless we need to shift into 4wd, but all the snow is gone for now). oh & yes one of the fuzes plastic cover was all melted off. that's what made me think that it was grounding somewhere. but it didn't blow, very strange.

[andy02]

DevilDog may or may not be right. Believe it or not, a bad starter ground can cause a fried CB radio. Now you tell me, if suddenly your CB went up in smoke, would you check your starter ground? The reasoning is simple, planes don't use the body as a normal electrical ground (at least none of the ones that I have worked on.)

Boodle, you have already started to zone in on this problem. The melted fuse is an indicator. Is that fuse lighting or t-case related? If not, then it is time to pull out the FSM and find out where the melted circuit fuse comes close to the back-up and T-case wiring. Take a look at this write-up on Stu Olson's site: http://www.stu-offroad.com/electrical/elec2/elec-2.htm

[CutterN55]

X2 for chasing the melted fuse cicuit. I'd also go with Devil Dogs suggestion (I am a "Tweak" too) on chasing common wiring. The shake method works great especially to find intermittant shorts to ground, or other wires/circuitry. Grab some beers, colored pencils, photo-copies of all the diagrams and a good meter & get to it. Best of luck

[SquiDMonkeY]

X2 for chasing the melted fuse cicuit. I'd also go with Devil Dogs suggestion (I am a "Tweak" too) on chasing common wiring. The shake method works great especially to find intermittant shorts to ground, or other wires/circuitry. Grab some beers, colored pencils, photo-copies of all the diagrams and a good meter & get to it. Best of luck

I am so glad im not the only one that does that. Everyone looks at me strange for having colored penciles in my tool box.