IMPORTANT ELECTRICAL INFORMATION (Long!)
Le Mans Master
Joined: Aug 2000
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From: Suffolk, Long Island NY
Burning Brakes
Joined: Jun 2002
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From: Troy MI
Originally Posted by Face
Pro
Joined: Apr 2002
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From: Denver CO
This Might be the Missing Information
Originally Posted by FRCTony
Me three.
:Cheers:
Originally Posted by Bill Curlee
IMPORTANT ELECTRICAL INFORMATION
Many of you have asked me for help on solving electrical problems and I thought this would be VERY interesting!
My 98 coupe would get the infamous "REDUCED ENGINE POWER", "TRACTION CONTROL FAILURE" and a host of random failure codes. After many, many hours of troubleshooting, replacing the BCM and TAC module, I solved most of the driveability issues. Still getting the random failure codes, I thought that I may be having ground issues. Back in June I cleaned ALL of the chassis grounds and the car virtually stopped throwing the "RANDOM" failure codes. Just moving the wires in the chassis ground connector was enough to change the indications and make the issues stop happening.
I had a chance to speak with some GM C5 Trouble Desk Engineers when I went to Bowling Green KY in April and they pointed out that MANY of the C5 electrical issues can be directly linked to chassis ground problems. The engineer even went as far as to recommending that I chop off the factory under hood chassis ground connectors and combine all of the wires into a single ground lug. Not wanting to just LOP off the factory connector, I took a chance and disassembled one of the ground plug connectors and to my surprise it was indeed full of corroded connections.
I strongly recommend that any C5 owner that has had or who are having electrical issues, examine and clean the chassis ground connectors. This may save you from needlessly replacing expensive electronics modules. Each connector can be disassembled and cleaned in about 20 min.
Just cleaning the ground connection between the chassis and the plug is only a bandaid solution. Now that I look back, when I cleaned my chassis grounds and solved my issues, I believe that when the connector is being removed to clean the connection between chassis and the connector, just the wires being moved inside the plug is what changed the indications and made everything work better. Disassembly of the chassis ground plug and cleaning the contacts inside the connector is the correct method of solving the issue!
I cleaned the two connections on the frame rails and the left one was significantly corroded! Taking it apart and cleaning it is a very straight forward procedure and I believe that if you follow this recommendation, you will be on the way to solving the many of the electrical issues.
There are approx 13 chassis grounds. There are two types of ground connectors. The eyelet type and the connector type. The connector type are the ones that are most effected by corrosion. The eyelets seem to be less affected.
Many of you have asked me for help on solving electrical problems and I thought this would be VERY interesting!
My 98 coupe would get the infamous "REDUCED ENGINE POWER", "TRACTION CONTROL FAILURE" and a host of random failure codes. After many, many hours of troubleshooting, replacing the BCM and TAC module, I solved most of the driveability issues. Still getting the random failure codes, I thought that I may be having ground issues. Back in June I cleaned ALL of the chassis grounds and the car virtually stopped throwing the "RANDOM" failure codes. Just moving the wires in the chassis ground connector was enough to change the indications and make the issues stop happening.
I had a chance to speak with some GM C5 Trouble Desk Engineers when I went to Bowling Green KY in April and they pointed out that MANY of the C5 electrical issues can be directly linked to chassis ground problems. The engineer even went as far as to recommending that I chop off the factory under hood chassis ground connectors and combine all of the wires into a single ground lug. Not wanting to just LOP off the factory connector, I took a chance and disassembled one of the ground plug connectors and to my surprise it was indeed full of corroded connections.
I strongly recommend that any C5 owner that has had or who are having electrical issues, examine and clean the chassis ground connectors. This may save you from needlessly replacing expensive electronics modules. Each connector can be disassembled and cleaned in about 20 min.
Just cleaning the ground connection between the chassis and the plug is only a bandaid solution. Now that I look back, when I cleaned my chassis grounds and solved my issues, I believe that when the connector is being removed to clean the connection between chassis and the connector, just the wires being moved inside the plug is what changed the indications and made everything work better. Disassembly of the chassis ground plug and cleaning the contacts inside the connector is the correct method of solving the issue!
I cleaned the two connections on the frame rails and the left one was significantly corroded! Taking it apart and cleaning it is a very straight forward procedure and I believe that if you follow this recommendation, you will be on the way to solving the many of the electrical issues.
There are approx 13 chassis grounds. There are two types of ground connectors. The eyelet type and the connector type. The connector type are the ones that are most effected by corrosion. The eyelets seem to be less affected.
Originally Posted by Bill Curlee
There are two connector type ground connections in the engine compartment. Both of the connectors are located on the top of the frame rails directly aft of the head light assemblies. The right connector os inboard of the coolant tank and the left one is in between the washer fluid tank and the head light assembly.
BTW, be sure to check battery post connections for even the slightest corrosion and for proper tightness. I was having wierd voltage fluctuations and "Reduced Engine Power" issues and found the positive cable connection to not be as tight as it should be and had a very little amount of corrosion. Cleaned both posts up, torqued them down (8-10 ft. lb., approximately, think factory says 11 ft. lb but I haven't verified.), checked the underhood grounds and my problems have gone.......thought it might have been a bad battery or bad alternator.
Last edited by TopCat; May 3, 2005 at 09:18 AM.
Le Mans Master
Joined: Dec 2000
Posts: 9,882
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From: Hot Springs AR
Bill,
I've got a friend with a problem where the voltage on the DIC reads about 0.5-0.8 volts lower than the voltage at the battery (measured between both terminals and between the positive terminal and a good chassis ground). I'm thinking we've got a ground with fair amount of resistance; any ideas which one to start with?
Thanks again for providing some great information, and have a good one,
Mike
I've got a friend with a problem where the voltage on the DIC reads about 0.5-0.8 volts lower than the voltage at the battery (measured between both terminals and between the positive terminal and a good chassis ground). I'm thinking we've got a ground with fair amount of resistance; any ideas which one to start with?
Thanks again for providing some great information, and have a good one,
Mike
Melting Slicks
Joined: Sep 2003
Posts: 3,306
Likes: 2
From: Wesley Chapel Fl
Excellent information Bill. Did you add any dielectric grease to the plug after cleaning? Wouldn't that help keep corossion from returning?
I removed the factory ground blocks on several of my grounds a while ago. After reading this I can going to remove all of them. Thanks.
I removed the factory ground blocks on several of my grounds a while ago. After reading this I can going to remove all of them. Thanks.
Team Owner
Joined: May 1999
Posts: 34,551
Likes: 505
From: Auburn Hills MI
Bill,
Excellent information. I'll check all this stuff out chasing my phantom codes also.
Most cars are on the verge of going over the capabilities of their current electrical systems and the C5 I'm sure is worse than others due to all the gadgets.
I can now see even a small variance from what was intended can and will cause problems.
Thanks again
Excellent information. I'll check all this stuff out chasing my phantom codes also.
Most cars are on the verge of going over the capabilities of their current electrical systems and the C5 I'm sure is worse than others due to all the gadgets.
I can now see even a small variance from what was intended can and will cause problems.
Thanks again
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Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
Bill; thanks much for this effort. I realize that stoppong to take pictures when repairing a problem slows you down - but it really helps the rest of us out being able to see actual pics of the areas.
Advanced
Joined: Feb 2005
Posts: 74
Likes: 1
I was thinking of cutting the connecter off and soldering all the grounds together on one lug, to eliminate the connecter. Do you know if anyone has done this? I noticed that the connect had wire numbers at each wire location. Is the wire harness built that way for some type of analytical equipment to plug in to it?
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Looks like GM uses that type of connector to allow different versions or options to easily be incorporated. What pisses me off is they go through extra effort to weather tight the +12 DC side but do nothing for the ground side. It is exposed to all of the elements
I spoke with one of the GM help desk techs and he said if the grounds are being a pain, cut them off and solder them into one eyelet. Guess what??? The C6 Vetts are built with soldered ground eyelets!!
That was one of the very first tings that I checked when we went to BG for the C6 unvailing!!
Along with the C5 ground connector issues, there are also Splice Packs all over the place that are going to corrode the same way one day.
Bill
I spoke with one of the GM help desk techs and he said if the grounds are being a pain, cut them off and solder them into one eyelet. Guess what??? The C6 Vetts are built with soldered ground eyelets!!
That was one of the very first tings that I checked when we went to BG for the C6 unvailing!! Along with the C5 ground connector issues, there are also Splice Packs all over the place that are going to corrode the same way one day.
Bill
Last edited by Bill Curlee; Jul 21, 2005 at 03:26 AM.
Thread Starter
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Originally Posted by VetteDrmr
Bill,
I've got a friend with a problem where the voltage on the DIC reads about 0.5-0.8 volts lower than the voltage at the battery (measured between both terminals and between the positive terminal and a good chassis ground). I'm thinking we've got a ground with fair amount of resistance; any ideas which one to start with?
Thanks again for providing some great information, and have a good one,
Mike
I've got a friend with a problem where the voltage on the DIC reads about 0.5-0.8 volts lower than the voltage at the battery (measured between both terminals and between the positive terminal and a good chassis ground). I'm thinking we've got a ground with fair amount of resistance; any ideas which one to start with?
Thanks again for providing some great information, and have a good one,
Mike
The battery is grounded to the frame at chassis G-104 and to the engine at G-106
G-104 is located inboard the battery on top of the frame rail.
G-106 is on the passengers side of the engine block just above the starter.
The generator is grounded to the engine block through the case to the generator bracket.
Any one of those connections could have high resistance. That is where I would start.
I connected an extra ground wire fron one of the case screws to Chassis ground stud G-101.
Try cleaning those ground points first.
Bill C
Last edited by Bill Curlee; Jul 21, 2005 at 03:16 AM.
Heel & Toe
Joined: Jun 2005
Posts: 21
Likes: 0
Electrical HVAC and Back up lights
Bill, This is great information. Any relationship with ths HVAC blower and my back up lights. I have noticed that when the blower is not working that the back up lights are also not working. I believe that the the grounding point is g202. I have recently corrected a corrosion proplem with the vacuum lines and wiring. All clean and vac problem repaired. Problem with HVAC existed before I corrected the cooresion problem. After this the only item left is a check engine light which is throwing codes that all O2 sensors are bad. Seems unlikely. I have a 97 with 70k miles. Very clean and lots of fun.. Plan on checking the ground point today. Any help would be appreciated.
VMI07
VMI07
Thread Starter
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
TTT
A LOT of people are starting to have ground issues again!! I need to update this post for 2000 -2004 C5. The ground points are a little different!!
BC
A LOT of people are starting to have ground issues again!! I need to update this post for 2000 -2004 C5. The ground points are a little different!!
BC
Team Owner
Joined: May 2003
Posts: 23,480
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From: East Meadow NY
St. Jude Donor '12
A general question on this issue. Are the grounds corroding due to disimilar metal connections vs heat and electricity or is it just water infiltration.
If it is just water infiltration, what product could be placed on it to prevent the rusting. Silicone grease, shrink wrap, whatever..
I change my own oil (as many others do), is there anything that can be put on these connections to help prevent this very common problem
Chris
If it is just water infiltration, what product could be placed on it to prevent the rusting. Silicone grease, shrink wrap, whatever..
I change my own oil (as many others do), is there anything that can be put on these connections to help prevent this very common problem
Chris
Thread Starter
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Chris
I drove my 98 a LOT durring the New England winters (Never in snow and real nasty weather) and the road salt may have had some to do with the corrosion issues. My 02 Z06 doesnt have any where near the corrosion that the 98 had but. I park it for most of the winter. I take it for a drive when the roads are clean every once in a while.
So yes, winter could have played a part in the corrosion issue. Then you have to look at this fact! Chassis ground G-101 (drivers side near the head light) was my worst chassis ground connector. Chassis Ground G-102 (passengers side head light area) which is the mirror image of the other connector was CORROSION FREE!
So,,there is more going on than just winter conditions!!
GM has admitted that these ground connectors are an issue and one of the engineers at the GM Technical Assistance Desk at Bowling Green recommended that I cut the connector off and solder all of the wires in a single eyelet and ground that! Guess what the C6 ground connections are??? They solder all of the wires in a single eyelet!!
BC
I drove my 98 a LOT durring the New England winters (Never in snow and real nasty weather) and the road salt may have had some to do with the corrosion issues. My 02 Z06 doesnt have any where near the corrosion that the 98 had but. I park it for most of the winter. I take it for a drive when the roads are clean every once in a while.
So yes, winter could have played a part in the corrosion issue. Then you have to look at this fact! Chassis ground G-101 (drivers side near the head light) was my worst chassis ground connector. Chassis Ground G-102 (passengers side head light area) which is the mirror image of the other connector was CORROSION FREE!
So,,there is more going on than just winter conditions!!
GM has admitted that these ground connectors are an issue and one of the engineers at the GM Technical Assistance Desk at Bowling Green recommended that I cut the connector off and solder all of the wires in a single eyelet and ground that! Guess what the C6 ground connections are??? They solder all of the wires in a single eyelet!!
BC
