Mystery engine harness plugs

[allthrottle]

I found these two plugs hanging disconnected the other day and have no clue what they go to. They're both behind the intake manifold, loomed into what seems like the main or injector harness. They must've been like that since I've had the car, but it's not throwing any CEL's and don't seem to be causing any noticeable issues while driving. I dug around and couldn't find anything unplugged. The a/c and all manifold/throttle body sensors are plugged in as far as I can tell. Any ideas?

Have a few pics at different angles. Sorry for the low quality cell phone pics.

 

[slvrDsm]

One looks like a ground connector.. Mine is on the right side of the intake manifold.. But mine is a 2g.. as far as the other one im not sure... is that a 1g??

 

[allthrottle]

Yup, '91 FWD GST. The only thing I haven't been able to get a real good look at yet are sensors on the back of the block or underside of the manifold to see if anything's unplugged.

 

[eeeewidner]

I have the same ones on my gst. The only conclusion that I can come up with is maybe they are for an automatic car. The plug in looks like it may go to the back up lights. http://alldatapro.com/alldata/PRO~V.../34869956/34869958/56472825/62720306/62619650

Look at connector E26 at the center bottom of the page..

 

[allthrottle]

Is it for the backup lights only on an auto tranny? I have a 5spd but my reverse lights haven't worked since I got the car. The reverse switch on the transmission is plugged in, and the bulbs are new.. I figured I just needed a new reverse switch.

 

[redyute1]

Un plug the switch jump the two wires in the connector, the harness side,turn the ignition switch on and see if you have back up lights.If you do then the reverse switch is faulty,if you dont then you have a wireing problem

 

[allthrottle]

Thanks for the tip Redyute. Tested it today, turns out the reverse switch IS bad, the wiring and lights are good.

I got under the car today to trace those wires. One disappears into the loom and I couldn't find any unplugged sensors, so I'm just going to assume I don't need it. The other ran to a relay or sensor of some sort that was bolted to the bottom/side of the intake manifold. I took it off and shot a couple of low res pics with my cell phone. Anyone know what it could be?

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[brownfinger]

Between the IM and the firewall is a connector that is used to do diagnostics on the AC at the dealership. The oval one is the one I'm talking about. You know how you can actuate sensors and relays with your logger? Well, that's so the dealership can do the same thing with your AC. I think. IDK about the one w/perpendicular terminals.
My car is bone-stock. Other than myself, I've hardly ever let anyone other than the local dealer touch the car. That connector has always been there. There is also the timing plug by the battery, and maybe one more little one for something else. They just hang out there. They're chill.

 

[cumpersgsx]

the boxy 2 pin connector looks like the one to your coolant overflow bottle on the bottom.