Big Three Replace Factory Grounds?

[iamdub]

Okay... Switched ground to side post and same thing.

All the wiggling I've been doing at the battery boils down to those wires running over the computer box and moving it. I rerouted the smaller wire that comes from OEM battery cable and back to frame ground where it was. If I apply pressure to the computer box toward the battery it does the stuff. Let off and it goes back to normal.

Do I have a computer connection issue? Is this common?

Hopefully I'm on to something. Thank you.

You're certainly on to something! Sounds like you've narrowed it down to a bad connection in the harness snapped into the PCM. Try unplugging them then plugging them back in firmly. But, it could be a wire or wires that goes into the connectors that plug into the PCM. You could inspect them to see if any look to be pulled out or just try to push all of them into the plug to ensure they're fully seated. I don't know how much slack there is, but if you could unbolt the PCM and have enough slack in the harness to have it up where you could work with it, you could gently wiggle or tug each wire until you find the one(s) that cause issues when you do.

 

[Dakcbeast]

Getting ready to head out now. I saw on another forum a guy had exact same issues and what he called "mud" on the pins. Cleaned them and problems gone. I may not get any trouble after rerouting just because there won't be any pressure from the wires on the box anymore, but that won't solve my problem totally. Here I go with a 7mm..

 

[Dakcbeast]

Pulled pcm out and inspected everything. The wire bundle on one looked to have some corrosion between the wires but I didn't see any bare metal? Going for a spin.

 

[Dakcbeast]

Nothing. Longer drive needed. Last night it was pretty much a constant. Only change is unplugging and plugging back in pcm connectors and rerouting wires so no weight on pcm box.

 

[Rolexus]

Hi All, new to this particular post, but I’ve got some serious ‘grounding issues’, such as EBCM, and Service 4WD messages that I’ve been working on.

Can some one give me a quick summary about what exactly are the “Big 3 Replace Factory Grounds”? Thanks!

 

[iamdub]

Pulled pcm out and inspected everything. The wire bundle on one looked to have some corrosion between the wires but I didn't see any bare metal? Going for a spin.

This stuff is pricey, but good. Honestly, owning an older GM product almost requires you to have this or something like it. You're almost guaranteed to have some gremlins from loose and corroded connections (PCM, window switches, etc.) eventually:

 

[iamdub]

Hi All, new to this particular post, but I’ve got some serious ‘grounding issues’, such as EBCM, and Service 4WD messages that I’ve been working on.

Can some one give me a quick summary about what exactly are the “Big 3 Replace Factory Grounds”? Thanks!

The "Big Three" are the three main circuits in a car's electrical system- Battery positive-to-alternator, battery negative-to-engine and engine-to-frame. Manufacturers use the bare minimum (if even that!) wire gauge to minimize costs, sacrificing some robustness of the electrical system. Upgrading the wire gauge and quality ensures all circuits supported by these circuits are getting the full amount of available power.

I think that it should be more of a "Big Five", adding body-to-frame (or engine) and battery positive-to-starter circuits. The body should be well-grounded since there are components inside that are grounded to the body. The starter is the biggest load on the system, so it makes sense to upgrade that while you're at it. Yes, it's only operated for a moment. But, allowing it to have all the amperage it wants will reduce the strain on the starter motor, making it stronger and extending its life.

 

[Rolexus]

Thank you for that explanation “iamdub” (sorry I misspelled your name earlier ), I will attack these 5 areas first, then eliminate the localized issues if still there.

The one I’m worried about is Service 4WD (have heard of people getting stuck in 4WH or 4WL). I’ve cleaned the frame mount grounds. I’ve found the small 4 pin connection on inner drivers fender, cleaned the 4 pin sockets, added dielectric grease and grounded the black negative wire to the firewall ground.

This was good for a week, then display came back. It has to be electrical - when the dash switch for AWD, 2WD, 4WH and 4WL are lite and functional, I can switch back and forth - no problemo!

After the above advice I should check transfer case control module and transfer case motor - plug-in sockets and ground wires.

Your thoughts?

 

[Dakcbeast]

Been driving around as stupid and foolishly as I can for the past hour and nothing yet. If only..

 

[Dakcbeast]

A few shorts drives today and nothing.