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Electrical- Intermittent Alarm, No Start with Key, and False DIC Messages

snomuncher

Full Member
Joined
Apr 4, 2004
Messages
53
Recently I?ve experienced several strange problems with the 2003 EXT. Once, at 2:30 AM, the content theft alarm went off (alarm sounds, lights flash) without any tampering, and it shut itself off after a couple of minutes.

Two days later I unlocked the doors with the key fob and the alarm went off instead. After shutting off the alarm, I started the truck and saw the ?Left Rear Door Ajar? message on the DIC, but that door was fully closed.

During the next week, I had left the truck parked for three days and unlocked it with the key fob, but the truck would not start. When I inserted any of the keys into the ignition, the DIC returned an ?Unknown Driver? message. The only way I was able to resolve this was to disconnect and reconnect the battery, then the DIC recognized one of my keys as ?Driver 1? and I was able to start the truck. Now I?m driving around with a wrench in the console in preparation for the next time I have to disconnect and reconnect should this happen again.

Anyone experience similar problems and have a resolution? Thanks!
 
Who installed the alarm? you might want to take it to the dealer as this sounds like a problem with your DIC.
HTH
Heavy D
 
Weird, but regardless of that, low battery and poor ground(s) develop. And guess what,.. the system goes nuts.

Several modules and accessory grounds go to splice packs. If that splice pack has a loose or bad ground, faults and strange things happen.

If it's still under warranty, flatbed it to the dealer so they can duplicate it (instead of the all-too-often "found nothing wrong, reset system" crap)!
 
Found one!
Document ID# 1371111
2003 Cadillac Escalade EXT​

Intermittent No Start, Service Stability Message, ABS Light Illuminated, Multiple DTCs, DIC Shows Unknown Driver, Various Electrical Related Conditions (Repair and/or Reroute Seat Wiring Harness) #03-08-50-014 - (Aug 20, 2003)

2003 Cadillac Escalade, Escalade ESV, Escalade EXT

2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2003 GMC Sierra, Yukon, Yukon XL

Condition

Some customers may comment on any of the following conditions:

* Vehicle intermittent no-start
* Service Stability Message
* ABS light illuminated
* Multiple DTCs set
* Driver Information Center (DIC) shows unknown driver
* Various electrical related conditions

Cause

1361690-Useat cable.gif


A chafed or pinched seat wiring harness under the driver seat may be a cause of this condition. Because of the routing, a portion of the seat wiring harness may rest on the inboard edge of the seat track or frame. Over time, the harness may be pinched or chafed because of the seat movement. Refer to the above illustration. The illustration shows the inverted position of the seat bottom. The arrow shows the primary location of the possible harness chafing/pinching.

Correction

Inspect the routing of the seat wiring harness. Reroute the seat wiring harness and attaching harness fastener (1) to the opposite side of the seat module bracket. Repair the harness as necessary. Refer to Wiring Repairs in the Wiring Systems sub-section of SI. The seat may have to be removed for ease of access and proper repair of the wiring harness.
 

Attachments

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Sperry: thank you for the info on the TSB. I checked out the under-seat wiring harness last night and it looks fine?no evidence at all of any chafing or damage but I see the potential for this becoming a problem. My next stop will be to the dealer to see if there are any DTCs stored. I saw another TSB number in the ALLDATA list associated with the keyless entry system (99-08-52-005A dtd May 03) but I don?t know if that one has any info that would be related.
 
Although I don't see it mentioned at GM's SI site, they seemingly are replacing BCM's. Mine was and pbuilder's too. I had a U1000 (Module communications) code setting and his was an HVAC fan problem...

I wouldn't be surprised if they address the above procedure anyway and also replace your's!
 
After the first trip to the dealer, they performed a number of diagnostics, researched stored trouble codes, checked the underseat and under dash wiring, but could not duplicate the problem. The tech called GM and got locations of more areas to check for chafed wires or loose tangs within connectors, e.g., wiring behind the radio and BCM. Because there were some trouble codes associated with the BCM and some chafed wiring in the harness to the rear door, they did not want to close my repair order but wanted to see if the problem occured again after all of the wiring checks, and later in the week there was another incident of the alarm going off by itself at 4:30 AM. Back to the dealer where more diagnostics showed an internal fault within the BCM. They replaced it today so hopefully that will solve the problem.

One interesting note about electrical problems noted by a technician: There is an area under the cover of the underhood electrical center that he says mice like to nest in and in the process they chew on wires, causing electrical problems.
 
Quote from SnoMucher;

One interesting note about electrical problems noted by a technician: There is an area under the cover of the underhood electrical center that he says mice like to nest in and in the process they chew on wires, causing electrical problems.

My first thoughts on this had to do with the random and odd hours of the mornings when the alarm would go off. Not knowing where you are located and taking your nickname into account, I figured the temps must be dropping to a point where the seat wires mentioned earlier may have been making a good contact.

Your comment on the under the hood Fuse Box actually makes more sense and is the least likely thing any of us would have thought to suspect.

I was starting to become concerned as there have been about 3 threads lately relating to seat wiring issues that would not normally be the first or last place to look for an electrical problem.

But then again, there sure is a lot of stuff under the seats and I didn't put it there.

I hope the problem is solved. Good find too Sperry! (y)

Now, about them varmits, Got Traps? :0:
 
I can see it now: "Mouse Trap Mod for EXT's" :eek:

He does have a good point; Rodent's chewed my brother's CAT5 wire into!
They can really mess up remote radio equipment too..

Did they try another Keyswitch? Those have been known to wreak havoc too.
 
argh. Just happened to my car.  Reading the post from my cell phone in a parking lot of a car wash where the car died. 

Unknown Driver, starts and dies off, no power windows, etc.  Solution, disconnected battery and reconnected.  Car woke up.

Think it must be a chafed wire under seat as the car washers rolled the seat back to vacuum. 

FWIW, I had another chafed wire before (a pink wire) on the steering wheel wiring..  These get chafed when tilting the steering wheel.  That one affects the signal lights.
 
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