Black wire connected to indicator lamp

[Dtrain]

Hi,
I have a 91 gmc suburban and am replacing the instrument bulbs with lleds. There is one black wire connected to a cluster gauge bulb socket, the other end has a small gauge plug style connector (almost like a jumper wire plug). Does anyone know where the wire plugs into? Could it be a warning signal wire from the body computer for the check engine lamp?
Any help would be appreciated.
Dtrain

 

[Goldie Driver]

Got a picture ? Sounds like the fiber optic plug on the right hand side of the cluster that illuminates the ashtray offhand.

 

[YakkoWarner]

If it is actuallly a black copper wire and not the optical lead mentioned above, good chance it is a ground (possibly for all the cluster bulbs?)

 

[Dtrain]

Thanks,
I thought that’s might be what it is. The lights recently stopped working but not the check engine service light. I’ll do some tracking tomorrow and see where it could connect to. Thanks for the idea!

 

[75gmck25]

It may be the black cluster ground wire. On older trucks it was grounded to a post on the top of the emergency brake, but I think newer trucks have some type of ground bus up above the pedals. I assume that the ground bus has posts or spade terminals and the ground wire(s) go on them. However, I’ve never looked at the setup on the newer trucks.