Electrical system strangeness

geordi · **Posted:** Thu Apr 28, 2011 4:48 pm

The computer in this CRD is starting to really drive me nuts.

While I was away a couple weeks ago, my father had the Jeep to use. He comes outside from a restaurant to find it going berzerk with the alarm, honking and flashing to wake the dead. No response from the key or remote to shut it up, and when it finally decided to be quiet (I think he might have stuck the key into the steering column) he couldn't get it to even crank over.

After looking and arguing with it for a while (while I was 3k miles away unable to do anything to help) it finally decided to start. It pulled a trick like this twice more, (the not starting thing) and the alarm once, so he started pulling the battery when stopped.

I come back, and everything is fine - Nothing out of the ordinary at all, just the constant and random binging that I haven't refilled the windshield fluid. Whatever, like I need to be binged at, like this is a critical failure?

Fast forward 2 weeks to yesterday. I'm driving to South Florida, 75mph on the highway, on the cruise, flat ground, smooth road etc. Without warning, the cruise cuts off. Like I had hit the brake pedal (which I had not). It did this 3 times during the trip, all without any warning at all. Hit resume, and it picked up right where it had been set.

Also during this drive, BOTH the ABS and brake lights came on with a bing, but nothing else. No blinking, no obvious problems, the brakes still operate fine.

What the hell is going on? Anyone have any theories or where to even look? I will be attempting to pull the codes today to see if there is anything there.

papaindigo · **Posted:** Thu Apr 28, 2011 5:32 pm

The first thing that comes to mind when electrical systems go nutso on one of today's cars is some combination of the battery, charging system, or ground. Too much or too little juice or an iffy ground can cause all sorts of weird problems now that everything is run thru relays, chips and fly by wire. First place I'd look would be to load test the battery and check the consistency of the charging system output. Not on my CRD but I've personally had random no start be traced to a short between battery cells, on a 1 year old 48 month battery at that, and on at least one occasion where the only way I could shut the alarm off was to disconnect the battery and reboot the system.

Electrical system weirdness, in fairness, is not limited to today's vehicle. I once owned an early 1970s vehicle where a headlight failure would cause the turn signals to go nuts and they were not even on the same fused circuit.

geordi · **Posted:** Thu Apr 28, 2011 5:49 pm

Interesting theory. I actually have a 2-year old Wal-fart battery that I had problems with in November. I took it back and they refused to replace it, only put it on their "magic" charger that determined that it was capable of 1080 amps out of 1000 rated. Interesting, as it had been giving me starting problems!

I did notice that my radar detector (which has a volt meter on the display) is reading 14.2 volts, which I thought was kinda high, especially after driving for a few hours. I think I'm going to start by replacing this battery tonight with one from Costco. I'm not happy with this Walmart unit, I only got it b/c I was stranded in the middle of nowhere, Va without a Costco within 3 hours.

bugnout · **Posted:** Thu Apr 28, 2011 5:54 pm

Maybe a sensor going bad?
Speed sensor on the differential?
Brake pedal sensor (do you have a brake controller?)
probably less likely a wheel sensor

Doesn't explain the alarm though

ATXKJ · **Posted:** Thu Apr 28, 2011 8:17 pm

check the battery in the key fob
my alarm was weird when that was going out.

yakers · **Posted:** Fri Apr 29, 2011 9:33 am

I had my CRD behave like it was possessed after water got into the fuse buss. Unbelievable the variations it produced. After I removed all the fuses and dryed things out with a hair drier everything has been fine.

geordi · **Posted:** Mon May 02, 2011 1:18 am

Well... So much for pulling the codes. My code reader seems to have wandered off, I just got back to Savannah so hopefully I can find the thing.

On the trip back up here, after 3 hours it dropped the cruise 3 times in rapid succession while at 73mph... And then it was fine for the rest of the trip, 4 hours. It did the same ABS / Brake light thing while running, so there (hopefully) will be a code in there.

On the other stuff that the CRD did with my dad, after talking some more with him it seems that the remote battery was causing it to go insane while he wasn't driving it... But he said it was also honking like crazy by itself while he was driving it. Anyone have any thoughts about that?

racertracer · **Posted:** Mon May 02, 2011 4:48 am

Sounds like you need to throw holy water on the beast.

Could a spiking battery be the cause? I read that wet cell batteries can spike up and down when in motion, or a bad cell is present. This could lead to the engine computer module to reset and the alarm, cruise control, lights, etcetera to go bezerk.

A dry cell design battery ensures extreme shock and vibration resistance and maybe the reason why Daimler/Chrysler decided to go with the Optima battery.

There have been past posts about members experiencing wacky behavior with their vehicles similar to what you are experiencing, it would be good to know what type of battery they have been using and the age, so we could compare notes and manage data.

:POPCORN:

geordi · **Posted:** Tue May 03, 2011 12:26 am

Ok, I finally got the codes pulled, and have those in a separate thread b/c I don't think they have anything to do with the weird behavior that the CRD pulled on my dad. The brake light binging while driving seems to be part of a failed level sensor code from the brake system.

Still don't know anything about the cruise dropping out... But I have now discovered some SEVERELY cupped front tires on both front wheels, but much worse on the passenger side. It would seem that the front struts are completely gone. Sooo.... I'm replacing those tomorrow, and swapping the tires from side to side. Hopefully that will burn down the cupping fairly soon. Arg, this thing is a pain in the arse.

nursecosmo · **Posted:** Tue May 03, 2011 7:13 pm

Was it raining at the time? I had an overcharge problem after I washed the engine bay last year. It caused all sorts of goofiness until the computer connection dried out.

I changed my struts a couple of months ago when I installed the Frankenlift II. I knew that the shocks were bad but had no idea that they were completely gone. I could push them in and out with about the force that it takes to move the slide on a trombone. The tires were becoming severely cupped because of the combination of destroyed shocks and destroyed ball joints. I'd check those too. Everything seems pretty tight now.

geordi · **Posted:** Wed May 04, 2011 12:58 am

Any chance I could get new ball joints from that recall, if they are problem?

How can I detect damaged ball joints? Wheel wiggle when jacked up? Noise while turning (there isn't any that I know of)?
Ditto for testing the struts - how? Trying to bounce the front end, I could barely get it moving and it stopped within 1 cycle. VERY hard to compress, but my CRD has always ridden like a truck. I have the replacement struts now (not in yet) but I wouldn't mind getting the $160 back that those things cost me if they really aren't bad.

I will say - I haven't replaced anything in the suspension since I bought the CRD, so that is at least 80k miles on the entire suspension system.

nursecosmo · **Posted:** Wed May 04, 2011 7:59 am

geordi wrote:

Any chance I could get new ball joints from that recall, if they are problem?

How can I detect damaged ball joints? Wheel wiggle when jacked up? Noise while turning (there isn't any that I know of)?
Ditto for testing the struts - how? Trying to bounce the front end, I could barely get it moving and it stopped within 1 cycle. VERY hard to compress, but my CRD has always ridden like a truck. I have the replacement struts now (not in yet) but I wouldn't mind getting the $160 back that those things cost me if they really aren't bad.

I will say - I haven't replaced anything in the suspension since I bought the CRD, so that is at least 80k miles on the entire suspension system.

You can be assured that if you have 80k on the machine, the struts are toast. They just don't last more than 50k and in many cases (the area where I live) less.

Test the BJs by jacking the front so that one or both wheels are at full extension, then use a pry bar between the control arm and knuckle to try to induce movement in the BJ. There should be none to very little. In my case I could see massive movement by simply rocking the tire by hand.

geordi · **Posted:** Mon May 09, 2011 6:29 pm

Ok! I now know that the ball joints are probably good... But the struts are still the original from the factory! Total vehicle miles of 108k, I'd say they are done too. Problem is, the replacement struts are sold without a spring, and my spring compressor doesn't fit. So I get to do this job a second time once I can order the ones WITH the springs. Arg.

On the electronics, I learned something recently: When the brake and ABS lights come on, the odometer stops counting. So I guess the next question is: Which sensor controls that? The speed sensor on the transmisson, or someplace else?
The speedo still works, but the EVIC mpg display goes to 0.0 my thought is this is the source of the original ABS codes too, but I don't know where to start looking.

mickkj · **Joined:** Sat Jan 15, 2011 9:59 am **Posts:** 7

yes, I had the brake, ABS lights too! Others on here have had it to. thats how i fixed mine. ABS, one on each front wheel hub
and one on top of rear dif. (ABS sensors) lucky for me so far it was the plug on the rear dif. been fine for three months.
your in the right place. OTHERS KNOW ALOT MORE but should get you started

WolverineFW · **Posted:** Mon May 09, 2011 9:52 pm

geordi wrote:

On the electronics, I learned something recently: When the brake and ABS lights come on, the odometer stops counting. So I guess the next question is: Which sensor controls that? The speed sensor on the transmisson, or someplace else?
The speedo still works, but the EVIC mpg display goes to 0.0 my thought is this is the source of the original ABS codes too, but I don't know where to start looking.

Since you have an 05 and therefore only one ABS sensor in the rear, I would suspect it might take a reading for the odometer from there. You might want to start by checking that sensor.

OldSkull · **Posted:** Tue May 10, 2011 12:07 am

If your cruise control get off and your odometer stop working good chance your electric cable connecting to the speed sensor on the top of the rear diff get cut, check closely it's a commun problem on the KJ and I dont remember the OEM part number of this cable but trust me wen I say check this first before buying a sensor... :wink:

PS: there is NO REAR ABS sensor on 2005 KJ It's a "WHEEL SPEED SENSOR"

Found it on my bill : 05013995AA

There is a thread about it here.... :-)

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=45557

geordi · **Posted:** Tue May 10, 2011 2:04 am

OldSkull wrote:

If your cruise control get off and your odometer stop working good chance your electric cable connecting to the speed sensor on the top of the rear diff get cut, check closely it's a commun problem on the KJ and I dont remember the OEM part number of this cable but trust me wen I say check this first before buying a sensor... :wink:

PS: there is NO REAR ABS sensor on 2005 KJ It's a "WHEEL SPEED SENSOR"

Found it on my bill : 05013995AA

There is a thread about it here.... :-)

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=45557

Merci! Thanks for that, I guess I get to look for a frayed wire tomorrow, as it has been intermittent for a while now. Might be grounding off onto something where it rubbed through.

Sir Sam · **Posted:** Tue May 10, 2011 2:18 am

I see my voodoo "doll" icon of Geordi's Jeep is working nicely.

Now onto my next trick.....a pin prick through the torque converter.

EDIT:

Seriously, I can't say $&? why is p-r-i-c-k a censored word? I pricked my finger, thats a big cactus $&! Have you met my friend richard? He's called dick by all his friends.

geordi · **Posted:** Wed May 11, 2011 12:54 am

I'm watching you bucko...

racertracer · **Posted:** Wed May 11, 2011 4:45 am

My brake light and ABS light came on. Checked the female connector at the rear ABS speed sensor and one wire was broken where it meets the connector. Replaced the connector and wire with a new one I got at the dealer and all is well.

It matters how the wires connect, they can only go on one way, so before you solder them make sure that you have them on correctly by checking that the brake light is off on the dash (the ABS light will not go off until you drive the vehicle) that is the only way you will know that you have the wires on correctly and that they are not crossed.

Electrical system strangeness

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