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ELECTRICAL "GREMLINS"

dlasic

Full Member
Joined
Aug 16, 2013
Messages
12
I am that member that willwham1 has had email contact with.  My '08 Avalanche with only 78,000 miles suddenly had major gremlins, much as he described.  Door locks started "cycling" up and down all on their own, my radio system would go out and lose all settings, my gauges would go crazy.  Worst of all when parked the truck went absolutely dead.  Jiggled the neg battery cable, the one that goes to ground at engine block and it would come back on.

Although I was going to replace all cables.  I went with the neg side first to see if this was what I believed a ground problem.  You see the vehicle has a low voltage side in the electronics that works through the CAN/BUS (computer aided network).  The body control module works a good deal of this and is often mistakenly replaced.  You see when the ground goes bad or weak the computer network modules go crazy and set all kinds of codes.

Being an old school mechanic having done a lot of fleet maintenance, I saw a lot of the basics missed.  Bad grounds being a big one.

First disconnect the battery and remove the original ground terminal from the battery.  You will be discarding the old terminal and ground wire that goes from the engine block to the battery.  Pull back and then remove the molded factory protecting cover from the neg battery cable end.  Cut the small 8 gauge wire as close to the original neg battery post connector as possible.  You will reuse this wire.

I used heavy gauge cable to make a new battery ground connection to the engine block.  With 0/1 gauge stereo amp wire (used as it has the least resistance per foot) I installed a proper flat terminal on the engine block side made of copper and crimped on the cable and used a 4 "port" gold plated car stereo type negative battery terminal.  This terminal takes 0/1 gauge, 4 gauge, and 8 gauge wire connections.  Cut the small 8 gauge ground wire that is attached to the factory neg battery terminal.  Cut close to the terminal to preserve its length.  This wire goes to the front radiator support area to ground the fog lights and other connections.  Remove the factory battery voltage sensor from the original cable (just unwrap the electrical tape and slide it off when taking the old cable out.  Make sure to note which side of this sensor is towards the battery post for reinstalling on the new cable.)  Install the newly made ground cable to the engine side first using "star" type lock washers to make a really good bite in the connection when tightened.  Slide the previously removed battery voltage sensor over the new cable ensuring the correct side of the sensor is towards the battery and hold in place anywhere along the new cable with wire ties or electrical tape. 

Install the new cable into the new battery terminal and tighten the set screw to hold in place.  Install the 8 gauge wire from the radiator support into the 8 gauge wire port of the neg battery terminal and tighten the set screw.  Now an important addition to your vehicle! 

Use 4 gauge wire cut to custom length that will go from the new neg battery terminal 4 gauge wire port across the firewall behind the motor over to where the factory has a braided ground strap attached near the hood bracket.  This strap is the cab ground it goes from this bracket at the firewall to the engine block at the rear of the motor.  You will leave this strap in place but will add the 4 gauge cable from the neg battery post to where this strap bolts to the bracket.  Also use car stereo amp cable for this connection.  This provide a fool proof ground to all the very sensitive computer modules inside your truck.  The ground is solid and stable as it goes right to the battery!  Again crimp on a copper flat connector to this cable end that attaches to the bracket.  Use the same bolt and lock washers the factory used for the ground strap.

Reconnect the battery.

You are now DONE.

No more gremlins and enjoy a fully reliable Avalanche, Silverado. or Sierra truck!
 
Do you recall how much wire you used, in 4ga and 0?


Fun Facts: oxygen free copper has less than 0.001% oxygen, when regular copper wire has around .04% max oxygen. Copper clad aluminum wire is less conductive than copper and OFC, but not by much.
Oxygen free copper will last longer than regular copper, resisting corrosion and is my personal choice when working on auto electrical. All brands of wire vary.    Just figured I'd share
 
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