Electrical What is this ground for?

ReefBlueGT

5 Year Member
Oct 4, 2018
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California
Hi all, 93 factory 5.0 manual convertible here. While taking out my instrument cluster for the umpteenth time, I decided to take a close look inside the dash, since I’m about to plug in my refurbished airbag module. Before I took it out, it gave me numerous codes for a few weeks, then finally settled on a 51. Then started the dreaded beep a couple weeks after that, even though the airbag light in the cluster was still flashing. So I figured it was kaput. Eager to try out the repaired one and see if that does the trick.

Anyhow back to my ground question. Since I wanted to be sure there wasn’t a short somewhere I took a look, and the ground on the body metal behind the cluster was touching the vacuum controller for the climate. Figuring that was not a good thing, I loosened it, reoriented it so the terminal was away from there, and tightened it back down. See before and after pictures below.

I have the EVTM for my model year, and that ground is diagrammed as G202 and listed in that exact spot, but that is the only mention of it. It ties into the harness that goes along the top of the dash then drops down to the window relays, courtesy light switches AND PCM. But the PCM ground is specifically called out as 201, directly below where it mounts. It would make sense that 202 might be redundant just in case but it’s odd to me that it’s not diagrammed anywhere in the PCM or any other circuit.

Anyone have any info or previous experience with this ground?

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The EVTM won't list the ground specifically, but where it's relevant it will show on the wiring diagram where the circuit connects to G202. You'll just have to skim and search all grounds to find it. One of the flaws of the EVTM.

I can take a peek at the EVTM later and see if i can find it.

But the ground touching the vacuum motor likely wouldn't cause anything. That motor would also be grounded so it's accomplishing the same thing
 
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The EVTM won't list the ground specifically, but where it's relevant it will show on the wiring diagram where the circuit connects to G202. You'll just have to skim and search all grounds to find it. One of the flaws of the EVTM.

I can take a peek at the EVTM later and see if i can find it.

But the ground touching the vacuum motor likely wouldn't cause anything. That motor would also be grounded so it's accomplishing the same thing
Good to know, thanks. All is well after putting everything back together and the repaired air bag module is working too :nice: