Sudden electronic problems

Ashaman074 · 07-09-2007, 05:48 PM

I seem to suddenly have a lot of electronic issues. I went out and started my 1998 Bravada and found half the instrument cluster non functional/lit up like a Christmas tree!

Here is a list of things that seem to have just failed together, so I imagine are somehow connected:

Battery warning light on (even though charging system seems to be functioning properly)
Fuel gauge dead
Temperature gauge dead
Overhead console dead (though it functions properly for ~60 seconds after engine start before displaying "C" and "--")

Last winter, I believe these all failed briefly a couple times while driving but it only lasted a couple seconds. It caused a "Hmm, that can't be good" thought in my mind, but no further problems. Unfortunately, after starting it up the other day, the problems seem to be permenant.

Additional problems include (I experienced these before the other problems):

ABS light suddenly on
AWD light on
Security light on
Wipers occasionally do not work
Climate control sometimes goes off and then right back on
Automatic headlights sometimes take a while to switch on.

Wow, after reading this it might have been quicker to list the electronics that STILL WORK rather than what failed, it is like an EMP went off in there!
For now though, the first group is more critical, if anyone has any ideas why they all would have stopped working at the same time for no apparent reason, I would appreciate it. Of course, any thoughts on the latter issues are not unwelcome either

S10dude · 07-09-2007, 05:55 PM

sound's like bad ground someplace...my brother's corvette had similar issue's and it was a poor ground for gauge's...

Ashaman074 · 07-09-2007, 06:09 PM

Thanks,....yeah, it seems like it would be - but where to begin looking? All the main ones at the back of the engine are in good shape, maybe behind the dash somewhere?

A really detailed schematic would be great; I bought one online but it isn't very detailed unfortunately

I hate to just start up an exploratory mission under the dash without knowing where/what I am looking for; so I thought I would check for input first.

Thanks again.

minitruckerdt · 07-09-2007, 06:13 PM

check your grounds...

Ashaman074 · 08-31-2007, 10:08 PM

Thought I would followup in case anyone else should have something like this happen - it was the ECM that caused the entire first group of problems, and possibly some of the others as well.

I went after the wiring armed with a diagram and found splice pack 201 under the dash. Basically serial data comes directly from a pin on the ECM to this pack, where it is distributed to the overhead console, the dash, the diagnostic connector, and the body control module.

I got a new ECM and the problems were immediately resolved. I wouldn't have guessed having most of my electronics die would have been caused by that, but in this case, they were.

Thanks to those who offered suggestions!

S10dude · 08-31-2007, 10:11 PM

good lookin out...it's nice to know of these problem's in case of such diasters...glad you got it fixed....

Tim99Zr2 · 09-02-2007, 02:54 PM

hmm. im having something similar.
a few of my gauges do not work aswell. how do i check my ecm? where is it located? the ecm fuse was good.

my truck battery died the other night so i got it jumped and drove home (running fine). didnt mess with it that nught, went out the next day and put the battery charger on it. it the had 14 volts in the battery, it sat there all day and i went to haul an engine lift to a guys house and the battery was dead again. 6.5volts in it. and i did not run it all day or leave lights on.

any ideas? maybe my alternator?

lesterl · 05-31-2008, 11:44 PM

Quote: Originally Posted by Tim99Zr2

hmm. im having something similar.
a few of my gauges do not work aswell. how do i check my ecm? where is it located? the ecm fuse was good.

my truck battery died the other night so i got it jumped and drove home (running fine). didnt mess with it that nught, went out the next day and put the battery charger on it. it the had 14 volts in the battery, it sat there all day and i went to haul an engine lift to a guys house and the battery was dead again. 6.5volts in it. and i did not run it all day or leave lights on.

any ideas? maybe my alternator?

Bad Ignition Switch?

07-09-2007, 05:48 PM	#1
Ashaman074 Registered User Join Date: Mar 2007 Posts: 20 Location: User is: OffLine	Sudden electronic problems I seem to suddenly have a lot of electronic issues. I went out and started my 1998 Bravada and found half the instrument cluster non functional/lit up like a Christmas tree! Here is a list of things that seem to have just failed together, so I imagine are somehow connected: Battery warning light on (even though charging system seems to be functioning properly) Fuel gauge dead Temperature gauge dead Overhead console dead (though it functions properly for ~60 seconds after engine start before displaying "C" and "--") Last winter, I believe these all failed briefly a couple times while driving but it only lasted a couple seconds. It caused a "Hmm, that can't be good" thought in my mind, but no further problems. Unfortunately, after starting it up the other day, the problems seem to be permenant. Additional problems include (I experienced these before the other problems): ABS light suddenly on AWD light on Security light on Wipers occasionally do not work Climate control sometimes goes off and then right back on Automatic headlights sometimes take a while to switch on. Wow, after reading this it might have been quicker to list the electronics that STILL WORK rather than what failed, it is like an EMP went off in there! For now though, the first group is more critical, if anyone has any ideas why they all would have stopped working at the same time for no apparent reason, I would appreciate it. Of course, any thoughts on the latter issues are not unwelcome either
	[Reply w/Quote]

07-09-2007, 05:55 PM	#2
S10dude workin it ! Join Date: May 2006 Posts: 11,029 Location: Sacramento,Ca. User is: OffLine	Re: Sudden electronic problems sound's like bad ground someplace...my brother's corvette had similar issue's and it was a poor ground for gauge's...
	[Reply w/Quote]

07-09-2007, 06:09 PM	#3
Ashaman074 Registered User Join Date: Mar 2007 Posts: 20 Location: User is: OffLine	Re: Sudden electronic problems Thanks,....yeah, it seems like it would be - but where to begin looking? All the main ones at the back of the engine are in good shape, maybe behind the dash somewhere? A really detailed schematic would be great; I bought one online but it isn't very detailed unfortunately I hate to just start up an exploratory mission under the dash without knowing where/what I am looking for; so I thought I would check for input first. Thanks again.
	[Reply w/Quote]

07-09-2007, 06:13 PM	#4
minitruckerdt Kiss my @ss Age: 26 Join Date: Mar 2007 Posts: 2,762 Location: the 530, Nor*Cal User is: OffLine	Re: Sudden electronic problems check your grounds...
	[Reply w/Quote]

08-31-2007, 10:08 PM	#5
Ashaman074 Registered User Join Date: Mar 2007 Posts: 20 Location: User is: OffLine	Re: Sudden electronic problems Thought I would followup in case anyone else should have something like this happen - it was the ECM that caused the entire first group of problems, and possibly some of the others as well. I went after the wiring armed with a diagram and found splice pack 201 under the dash. Basically serial data comes directly from a pin on the ECM to this pack, where it is distributed to the overhead console, the dash, the diagnostic connector, and the body control module. I got a new ECM and the problems were immediately resolved. I wouldn't have guessed having most of my electronics die would have been caused by that, but in this case, they were. Thanks to those who offered suggestions!
	[Reply w/Quote]

08-31-2007, 10:11 PM	#6
S10dude workin it ! Join Date: May 2006 Posts: 11,029 Location: Sacramento,Ca. User is: OffLine	Re: Sudden electronic problems good lookin out...it's nice to know of these problem's in case of such diasters...glad you got it fixed....
	[Reply w/Quote]

09-02-2007, 02:54 PM	#7
Tim99Zr2 Fvck New Jersey Age: 21 Join Date: Mar 2007 Posts: 7,535 Location: Reynoldsville, PA User is: OffLine	Re: Sudden electronic problems hmm. im having something similar. a few of my gauges do not work aswell. how do i check my ecm? where is it located? the ecm fuse was good. my truck battery died the other night so i got it jumped and drove home (running fine). didnt mess with it that nught, went out the next day and put the battery charger on it. it the had 14 volts in the battery, it sat there all day and i went to haul an engine lift to a guys house and the battery was dead again. 6.5volts in it. and i did not run it all day or leave lights on. any ideas? maybe my alternator?
	[Reply w/Quote]

05-31-2008, 11:44 PM	#8
lesterl Wire Splicin Fool :-) Age: 30 Join Date: May 2008 Posts: 4,413 Location: Harrisonville, MO User is: OffLine	Re: Sudden electronic problems Quote: Originally Posted by Tim99Zr2 hmm. im having something similar. a few of my gauges do not work aswell. how do i check my ecm? where is it located? the ecm fuse was good. my truck battery died the other night so i got it jumped and drove home (running fine). didnt mess with it that nught, went out the next day and put the battery charger on it. it the had 14 volts in the battery, it sat there all day and i went to haul an engine lift to a guys house and the battery was dead again. 6.5volts in it. and i did not run it all day or leave lights on. any ideas? maybe my alternator? Bad Ignition Switch?
	[Reply w/Quote]