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Topic: Electrical nightmare & bizarro brake issue (long post, sorry!!)

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Electrical nightmare & bizarro brake issue (long post, sorry!!)

 

 

I will start with an apology for a long winded post regarding 1st an electrical nightmare and second a bizarre brake problem:
Electrical: A couple months ago my left turn signal stopped flashing, had to manually move the lever, but still lit so I just dealt with it. Then at the beginning of April, my running lights went out entirely; no tail, parking, side markers or turn signals. I checked the fuses & replaced the fuse that was blown with an identical fuse, 25a (markings are gone on the box so I had no idea what was needed, but should've been 10a!) Well everything came back on except that pesky left turn problem. Well, after 40 miles of driving as dusk approached, I turned on the lights and 10 minutes later the cab filled with smoke!! Well, I pulled over & killed the engine & lights, then looked under the dash at the fuse box and the park lamp fuse was melted! Now I drove the rest of the way minus lights and the next day drove home. Fast forward a month of driving only in daylight as I have had no time to work on it at night being a single father, but I finally had an opportunity to begin a thorough inspection last week and I found a wire in the wiring harness behind the grill that was completely burned through, no insulation left at all which of course melted several others. I followed it from there into the engine compartment along the driver's side inner fender to a grey plug, burned the entire way. It was also burned on the other side of the plug and melted to other wires all the way to the pass through connection on the firewall. I then went under the dash, cut away the electrical tape from the wiring harnesses and found more melted wiring. One was blue & went to the headlight switch where it connected with another blue wire at the "R" connection on the switch. 1 of the blue lines went up into the dash behind the cluster, the other was so far gone that it broke while tracing it down, BUT there was also another completely toasted line which I determined to be red with a blue tracer from the melted insulation stuck to the other wiring in the harness, it went to the fuse box for the park lmp fuse. This came from connection "B2" on the switch & also had a twin red w/blue tracer in that connector that went up into the dash. The orange w/black tracer from "I" to the inst. lamp fuse was burned as well (these were ALL 18ga wires), the red 12ga line to "B1" from the splice was burned as well. I replaced all burned 18 ga lines with 14ga wire & 10ga to the "B2" connection and the rest to where the existing lines were intact and soldered them together & used heat shrink on the connections. I replaced the head light switch from a newer model bone yard find that had 3 extra connections (U,P & B3) but the rest were identical so I see no issue with it though I did order a new switch from rock auto prior to the BY trip. Anyway, I now have both signals front & rear flashing, but my headlights have no power and my running lights keep blowing the fuse, even if I throw that 25a fuse in there. Will I need to start from scratch & replace the lines from the switch to the front lights and again all the way to the rear lighting plus up into the dash as well? should I use the 18ga where it was? I was planning on the headlight upgrade so I have no issue doing that now but that rats nest under the dash is a nightmare!!! There have gotta be 50 black lines, 25 orange w/tracer, 10 whites blues etc...plus there is a relay that the wiring was burned up on under the left dash or kick panel as well, but I can't find it on any wiring diagram/schematic anywhere!!! I do not have fog lights...so its not for them. Brakes: This is weird. My brakes work fine 99% of the time, but when I parallel park or cut my wheels hard in any direction, 3 point turns, etc. I lose 90% of my braking. The pedal will go flat to the floor! A terrifying experience the first couple of times...but now that I expect it, I pump my brakes and they work fine again. I have no leaks in my system, no fluid loss and no vacuum leak. I replaced the check valve on the booster to no avail. I ordered a new booster and master cylinder yesterday, but if that isn't it, what can it be? Has this ever happened to anyone or have you heard of it?? As I said, only happens if I turn wheels to the stop or 3 point turns, never going straight or making regular turns at intersections.
I'm at my wit's end here & appreciate any help, thanks!

It's a 1990 Laredo 4.0, fairly stock other than injectors, ignition & 2" lift



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First off, Welcome to glxj

 

Second, I am not the person to comment on the wiring, I absolutely cannot grasp the concept of it, I get confused everytime.  You said that you have looked at diagrams etc.  Do you have the Factory Service Manual?  If not you can download it from the Tech page of this site found HERE

 

The Brakes, I don't know either.  The only thing that I can think of is one of the lines are getting pinched or something when the wheels are locked... I would have someone crank the wheel for you and climb under there and make sure. Then if that isn't the problem I would start checking to make sure everything is tight and attached properly.

 



-- Edited by aci4369 on Sunday 22nd of May 2011 10:16:32 PM

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I have the FSM, its about the size of a Chicago phone book! I also have it downloaded as well. I have decided that I will be starting from scratch today, front to rear replacing all wiring involved in the lighting, eliminating the connectors and replacing the relays in the back panel. I'm going with 12ga wire for the most part and doing the headlight harness upgrade using 10ga and separate relays for hi & low beam...I'll post back when I finish and give a positive or negative result...hoping positive!

As for the brakes, I have checked everything! I will be bleeding the lines just in case there is air in there and replacing the rear shoes today or tomorrow...with storms in our forecast, I am at mother natures whim!

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The only help I can provide is....GOOD LUCK!!

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HAHA! Thanks! I need all the luck I can get! I spent 15 hours on it yesterday & (drum roll) Nothing! Worse, I made errors in the dark wiring the battery! lol Well I have 5 hours of light today, so I'm back to it. Surgery tomorrow AM so I gotta get it back to at least daylight running mode!



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What did you get done yesterday, with no results? Did you get the rewire done?

Do you have any lights now at all ? Brake, turn, or running ?

Where are you in Chicago ? I really won't have time till after next week, but after that .... Not much help when your in your kind of situation and every day seems like a lifetime. I know.

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Man that sucks.



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Nothing at all now, no headlights, brake, running etc. Gonna check fuses first then one wire at a tiume go through the nest under the dash. I removed a bun ch of useless wiring I believe was prt of the old alarm, I hope it wasnt anything I needed but I doubt it, it was spliced in via insulation removal with bare wire wrapped round the exposed lead...Anyway, I rewired from the switch and tied in above where the melting occured, I also did the upgraded headlight loom to see if that would help. The problem is a few of the wires that melted eliminated all trace of insulation so its a guessing game and also whoever went under and added the alarm & stereo 15 years ago made a mess of things and we have terms for that on the South Side I'll refrain from using ;) At anyrate, I rewired to the fuse box for the parking lead, new headlight switch, new leads under hood. result is no lights at all, but it was 1030pm so I hope I vcan find something I missed between now and 9pm tonight when light fails. I had gotten turn signals the previous day, so I know I found part of my issue. I am in Bridgeport and if this is still a problem in a couple weeks, I'll gladly accept help! Thanks!



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I saw you were on NAXJA, I believe. I did a quick search there and they have a number of good tips.
1) Do you have a VOM ?
2) Appears that the Light switch is a common problem, the rewire and addition of the relays should reduce the load on the switch so this shouldn't be a problem assuming that the switch is good.

Did a quick search for replacement wiring harnesses and found none. Something like a Painless harness with an additional 3 or 7 fuses may help get around the fried wires. But then it really all depends on what caused the original problem. The turn signal may, or may not, have been totally independent of what you are experiencing now.







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Steve Martinek
SW Michigan.

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1967 Mustang Fastback - future project - waiting for CJ8 to get done

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Well, this is why I don't like electrical stuff.  It doesn't make sence... lol

 



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Ok, well after starting on this again Tuesday afternoon and working through the night til (am yesterday morning I have apparently resolved the running light & turn signal issues. Of course then the truck wouldn't start...go figure! So in the middle of God's wrath of rain & lightening I traced the problem to my MSD coil which appears to have a cracked tower and was arcing to the mounting post. Still, no headlights. I'm laid up now after knee surgery, but after exhaustive thought and study of schematics from FSM and other sources, in addition to the burned up connector & OE switch, plus a switch out of a '90-'91 Voyager, I feel that with the loom upgrade I'll need to go through the firewall with my switch control, as opposed to wiring through the old harness lines. Perhaps rewiring both the low & high beam back to the dimmer switch on the left of the column using the upgraded 14 gauge wire and adding inline fuses to each (just in case). I'll probably be doing this tomorrow if I'm up to it, hell its a work comp injury & the city of Chicago owes me quite a few favors, maybe I'll drop it off in a city garage & let them fix her for me! Almost 400k miles I've put on her driving back and forth from Camp Lejeune & running around at all hours and in all weather conditions making sure the water was flowing for the great citizens of this city! Or I'll just do it myself while nursing my knee...oh the decisions! LOL I'll post back when I have more news...

As for the VOM, yes, both digital and analog. And the Painless system, it isn't "painless" to buy it! haha! I have time and the wire is free, granted its not automotive, but its from the Dept. of Trans. and they use it for the streetlights etc. so it is high quality and stranded...of course the price is right!
I'm glad to have the work though, I've been off doing nothing because of this damn knee & while wiring issues really blow, I am learning a lot. I bought this truck new in late '89 and she's been good to me, doing this will help me with the CJ & YJ sitting up at the cottage when I get a chance. My daughter will be driving this down to school come August, I've got time to bring her to her former glory I hope! Thanks guys, soon as I get a new card from the bank I'll be joining the club!!

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Painless harnesses are expensive, but a lot of guys swear they're worth it. I'd go with them if I were doing a 'engine harness' or a full harness, but just headlights I think I could handle myself.

I'd probably pull the factory harness (taking notes and pictures of routing and such), then making the new harness based off the old one, preferably using heavier gauge wire.

Matt

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Ok here is the deal. What started your problem was the left turn signal. One of your bulbs went bad. Which didnt load the flasher properly so no flash. After you ignored the problem the bulb eventually shorted out which caused the fuse to blow. You replaced the fuse but still never checked the lights and with the increased current flow allowed by the bigger fuse it toasted the system. "For the want of a 59 cent part the race was lost."
Good luck with the rewire but check your turn signal bulbs before you repower the system. Im sure youll find one of the bulbs is bad and probably shorted to ground internally.

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New guy here, but experienced with XJs.

One thing I found out about the flexible brake lines at the calipers is that they can narrow internally with age and cause pressure differentials with the braking ability. It is possible that your problem with the brakes is right here. The thing that makes me suspicious of this is that your issue happens with turns and that turning stresses the flexible lines normally. I'd replace the lines on both front ones and bleed the brakes thoroughly after.

It looks like you're trying to do the electrical repairs on the cheap. I certainly can understand why. Unfortunately, that can also be part of your dilemma with diagnosing and repairing. Locating burnt wires one at a time and splicing is a time consuming job and it's possible to miss one that hasn't burnt all the way through the insulation or the damaged portion is well hidden from view. This happened to me with my Ford truck when several main ECM harness wires burnt and took the computer with them. It took forever to locate the damaged wires. What I'd do is to get a junkyard harness and replace it section by section until the problem is resolved. One couldn't possibly be that expensive.

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AlanB wrote:

Ok here is the deal. What started your problem was the left turn signal. One of your bulbs went bad. Which didnt load the flasher properly so no flash. After you ignored the problem the bulb eventually shorted out which caused the fuse to blow. You replaced the fuse but still never checked the lights and with the increased current flow allowed by the bigger fuse it toasted the system. "For the want of a 59 cent part the race was lost."
Good luck with the rewire but check your turn signal bulbs before you repower the system. Im sure youll find one of the bulbs is bad and probably shorted to ground internally.


This cannot be true! If this were to be the case there would be no vehicle on the road as we would be seeing fireballs all over the place of burning vehicles caused by a blown bulb. Anybody knows that the only effect of a dead bulb to a vehicle are rapidly flashing indicator lights and not a burning fuse box!

Certainly your problem is consistent with short circuit but I dont see how a blown bulb filament would do that..... I also do not think that the problem was caused by the replaced fuse as it is that replaced fuse that would have itself blown after replacement. The problem therefore must have originated elsewhere and most likely as a result of a non fused circuit.

All the best as you solve the problem. I installed fresh ABS system in my Jeep recently and I agree the wiring can sometimes look like a bird's nest and very intimidating. But with your Jeep model year wiring diagrams and lots of patience you will be good to go....



-- Edited by PlayStation on Monday 8th of August 2011 07:44:26 AM

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