Got a 2005 C6 that ive only had 6 months and keeps having electrical problems with this car! I noticed my tail lights keep turning off randomly at night while im out driving but they only do it at certain times, sometimes they stay off for a couple hours and then theres times where they go off then come back on minutes later so i checked all fuses in the fuse box under the hood and in the passenger floor board and they all checked out good. So i looked on the forums and ive read that people say there is problems with corrosion in the main tail light plug thats in the bumper behind the tail lights so i took the tail lights out and checked all plugs going to the tail lights and the main plug and no corrosion and plugged in tight so i traced wires all the way up to the BCM and wiring seams to be fine, Also checked ground behind passenger seal and the ground thats by the passenger door footwell and when i pulled the bolt out of the eyelet for the grounds the wipers came on and off which is another problem im having the wipers do not work. brake lights,turn signals,headlights and front paking lights all work just not the tail lights. any ideas what might be my problem im kinda at a loss now? starting to think the BCM is bad

 

Would start by disconnecting the battery, then the BCM Blue and red connectors to make sure that they are clean and dialectical greased.

At the same time, would double check the loom runs of the blue connectors to make sure there is enough slack in them where the one comes back under the passenger carpet that someone over in the passenger seat is not pushing hard enough against the carpet (and loom under the carpet) that it causing the blue connector connection problems as well.

If you take a look will note that both the center red and right blue wire looms come back across the carpet in the passenger foot well, and GM did have a problem with not enough slack in the looms to prevent someone pushing hard against the carpet over there causing disconnect problems on some of the terminal pins to the BCM connection points.


Also to point out, there are a few other connectors under the passenger carpet as well (one that leads back to the tail lights) that may have the same problem as well. Its no joy to get them since you have to remove the passenger seat first, but not out of the question if needed.

If not a tight wire loom problem, then are you sure that you did not get a flood car????

With the problems your having, it's screaming that the interior of the car go wet to cause all kind of electrical connector problems. Hell, it could have just been that the Hvac air box drain got clogged and was not cleared, and instead the condensation water in the air box draining down out the line the ground, the clogged line caused the water to drain out to the BCM and passenger floor area in the car instead.

The drain line for the air box on the the passager fire wall in the engine back, on the bottom inner side bottom just before the U channel of the drive line to come back. you can't miss if when looking up from under the car.



As for if the BCM is the problem due to water getting in it, it not the end of the world most of the time. You can pulled apart to check its board to clean up signs of water damage that need to be repaired; if you have the talent. God knows I have lost count of all the modules that I have pulled apart over the years to repair them; instead of spending the huge bucks having to replace them with new ones instead.

 

Thank you for your information! I was indeed a flood car but got the car fairly cheap and I also took all the connections loose at the bcm and checked for corrosion and it was clean I also put dielectric green on all the plugs going to it as well! I'm going to pull the passenger seat tonight when I get off of work and try checking the loom under neath the carpet because it always seams like it has the electrical problems when I have a passenger in the car. I've been driving down the road and the car randomly dies and I pull over and mess with wires at bcm and then it works fine again. So it might be the wires under the carpet like you stated above! I'll check those tonight and I'll post back. Thank you again for your information

 

Ive been helped by this forum more times than I can count. One area that is notorious creating electrical issues are the grounds. Our car has plenty of them and if you go to sticky's post you'll see where they are. Being a flood car that would be the first place to go and clean all of them and protect them with dielectric grease, after you clean and reinstall fresh metal to metal contact. Gook luck

 

Ugh. Check everything.

 

found out what the problem was!! ended up being the wiring underneath the fuse block under the hood. There had been the wires for the tail lights and wipers in the same look that had rubbed threw, replaced the wires and all fixed! Thanks guys for all the info.

 

I have a 2008 very clean LS3 with 31K miles. It was a "water damaged" car and had 17K miles with damaged/ recovered title when I got it for cheap. It runs like a watch and perfect in every way... except- the park shift lock solenoid (good solenoid) does not get juice until about 30-120 seconds of having your foot on the brake. Then all the sudden "click" (sound of solenoid engaging) then OK. Pretty sure the Microswitch is bad under the console. I am afraid to take the plastic cover off!

Next issue now. 2 years ago, can't connect to computer port (ECM) for inspections, etc. Connect ANY scanner and SOMETIMES, LOCK symbol sometimes comes on and car goes into a "limp mode" won't shift gears. Solution- RANDOM: turn car off. Click FOB to lock and unlock a few times. Clears- PERFECT - for a while. Or just wait 10 minutes for LOCK (yellow security lock on left lower side of cluster, BTW). ALSO of note, when this happens, the shifter lock solenoid can be heard clicking on and off.

Now it has gotten worse. Lock symbol appears RANDOMLY like a turn to the right under acceleration may cause this. Or going from Drive to reverse and back with a little acceleration. Car shuts down and won't start, door solenoids stick. Can't shut doors (or open). ALL gauges ZERO out (except Alternator gauge is OK). Try to start and NADA, ZIP except light ACCY in push start button light. SOLUTION: lock/ unlock repetitively with key FOB. (Door lock unlock buttons do not appear to respond. And if the door is open, the door solenoids (driver and passenger) are in CLOSE position and an attempted door close and BAM! strike pin HITS the closed solenoid captivating C latch. Turn signals stop working. Seat belt reminder does not work. Alarms sequence through the display - Antilock Brake failure (with red brake light lit), Service Vehicle, Fuel system, Low fuel, but mostly BCM items (?) with the exception of those power train ones. I have a loose ground or bad computer. Another thing, the exhaust cutout activates every time this happens. The "BMW Limp mode" where it stays in 1st or second gear does NOT always happen. I drove it 20 miles like this yesterday. You have to pull the manual door lock release to get in and out (windows work but the window crack feature does not work). Loose ground or bad computer? I wonder if the computer connectors are bad from the Hurricane Sandy flood event.

There is a loose ground SOMEWHERE! Anyone know where it might be? Or BCM/ and or ECM going bad- corroded connectors from Hurricane Sandy flood damage... car was partially submerged. ECM/PCM or whatever you call it is down low behind passenger side fender which makes it appear to be a pain it the butt to get to it. But! maybe I should start there. Disconnect battery and pull the connectors and inspect for corrosion? ARE THERE ANY MULTI JUNCTION GROUND POINTS that are easier to get to that may cause random electrical issues?

 

“Now it has gotten worse. Lock symbol appears RANDOMLY like a turn to the right under acceleration may cause this. Or going from Drive to reverse and back with a little acceleration. Car shuts down and won't start, door solenoids stick. Can't shut doors (or open). ALL gauges ZERO out (except Alternator gauge is OK). Try to start and NADA, ZIP except light ACCY in push start button light. SOLUTION: lock/ unlock repetitively with key FOB. (Door lock unlock buttons do not appear to respond. And if the door is open, the door solenoids (driver and passenger) are in CLOSE position and an attempted door close and BAM! strike pin HITS the closed solenoid captivating C latch. Turn signals stop working. Seat belt reminder does not work. Alarms sequence through the display - Antilock Brake failure (with red brake light lit), Service Vehicle, Fuel system, Low fuel, but mostly BCM items (?) with the exception of those power train ones. I “

Did you ever get this part resolved. I’m having the same issue with a corvette I bought a few months ago. Nothing in the vehicle history showed water damage but you never know. Changed and rewired the BCM the shop went through all the grounds but the problem still comes back, the past couple of times when I pushed the windshield washer. If I disconnect the battery it all resets then is ok for a short while.
It’s a 2005

 

Marked

 

Sorry for being late here ... These cars suffer from a huge electrical issue ... In your case is even worse cause you have a flooded car ... I you haven't fix it or still have some issues ..I suggest ...remove both fuse boxes I mean the only fuse box is the one in the engine the other one at passenger side is the bcm which is full of fuses also ...remove everything... Even all electrical components inside the car ...can take you the whole day but that's fine you gonna love to put your hands on your car ...remove all of them ...spray some electronic cleaner ...cost like 7$ at any auto parts even walmart has it...spray several times all the connections... Put dielectric grease ...clean up all the grounds ... Be sure your battery is good 12.6 is the right voltage to start your vette ...remove the battery also ... Remove the connections that come from it to the bcm and starter ... Take pics before you remove everything and at the time to plug back you know where everything going to be connected... As I said is a big project but worth it ...just be careful you don't brake anything ..plastics...wires...etc ...good luck and let us know how was everything... Cheers

 

Hi folks,

Electrical problems on my 2005. Symptoms of a dead battery. No power to get in and had to go through the trunk. The only thing that had power was the footwell lights and the radio. Took the battery to have it tested and it was ok. Checked all the fuses under the hood and they're good. Now here's the big problem. I can't check the fuses in the passenger footwell because I can't get the passenger door open. There's no emergency door opener for the passenger side.

Anyone have any suggestions for both problems?

Thanks in advance.

 

First get into the car and open the hood and see if underhood fuse 11 is hot…it is the ECM/TCM/EASY KEY…how did you check the fuses ??…best to check with a 12 volt test light…not a DVOM…do you have a no FOB detected message…does the car start when placed in the glovebox slot ??…we need more info !!…battery terminals tight at both the battery and at the starter solenoid and the block ground ??…BTW there is a release lever on the passenger side floor to open that door…is this car new to you ??

 

Thanks for the quick reply. I've had the car for about 12 years. I've never really surveyed anything on that side since I always drive. Now that I think about it I believe I did see it there.

I'm old school and use a rest light and also former ASE certified mechanic. That fuse was the first I went to and it is hot. I made sure the battery terminals were clean and tight. I also tried another battery and it reacted the same. I haven't checked the starter wiring yet since the second fuse box is the easiest to check once I get the door is open. I won't be able to get back to it until Friday. I'll let you know how I make out.

Thanks again.

 

Just let us know what is powered and not powered other than your interior courtesy lights and radio …if you have a factory level or equivalent aftermarket scan tool and hopefully you do as an ASE mechanic see what modules you can and can’t communicate with…I’d check pin 16 at the DLC if you can’t communicate with anything.