Green Wire at firewall Harness Connection

[jaylin]

Hi everyone, I have been working on a 1997 Chevy 1500 WT.   I just happened to be working under the dash and noticed that the green wire that goes into the firewall harness connection was disconnected.  Does anyone know what this green wire is for? (please refer to photo below) I looked at the wiring diagram and it looks like it goes to the MAF which I think is for the speedometer operations.  Now my second question is, if it is for the MAF where should I try to reconnect.  I obviously can't get it back into the bulkhead.  Can I bypass the bulkhead and run a jumper wire?

I would be appreciative for any help.

Thank

Jaylin

[Brian Lindsey]

looks like something aftermarket , can you trace the wire back, it doesnt look factory, did truck have a brake controller in it at some point

[jaylin]

All gauges work except for the speedometer. I checked the speed sensor with a obd2 and it registers the speed however nothing from the cluster speedometer.  Looks like the wiring diagram shows that the speed sensor wire from the cluster  to the firewall is a dark green wire.  I tried a jumper to the other side of the firewall, but experience no change.  Can anyone Help?

Thanks

Jay

[riverbanks]

With the scannerdo you see MAF operating?and fuel system closed?then it's nothing to do with that, give a better picture higher in harness