Does anyone know what this wire is for? It's located behind the alternator and by the coil. I have no ignition or charging issues so I'm not sure of its purpose.

I apologise for the large image as I'm on my mobile so can't shrink it like I normally would.

Thanks

I have the same one disconnected, I thought it went to my A/C

It is for the Go Fast device. Someone removed it! And they are hard to come by.

Ah, yes the Go Fast device, I knew it!!

You guys talking about this?
I see them from time to time on Ebay. Can't seem to find one at the moment though.

So you all you need to do to disable is disconnect the plug with blue wire?

I've read different opinions about the Power VS Comfort setting. Some say if enabled leave it in Power mode for the best fuel economy while some people and owners manuals shows the Comfort setting produces better fuel economy.

From NAJA
"
According to my owner's manual for my '88 Laredo, the blurb states:
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AutomaticTransmission Mode Selection Switch

Automatic transmission mode selection allows you to select different transmission shift characteristics to suit your driving style and road conditions. The switch has two positions:

Power: In this mode the transmission will be more responsive. It will upshift at higher speeds under hard acceleration and downshift more quickly. An amber indicator light on the switch will glow in this position.

Comfort: This mode is for normal driving. The transmission will upshift at lower speeds for more economical operation.
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Also there's several different posts with different methods of how to disable the Power / Comfort switch. Perhaps it depends on the year?

e.g.

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Bypassing the Power/Comfort Switch on a Renix Jeep

Remove and unplug the switch. In the harness are 3 wires One has a stripe, one is tan, and the other black. Make a 4" jumper wire with a male spade at each end. Plug one end in the cavity for the tan wire and the other in the cavity for the striped wire and you'll be in permanent Power mode. Stuff the harness back in and reinstall the switch for looks.

If you happen to have a 91 or 92 XJ/MJ and it has the Power/Comfort switch, just jumper the Tan and Blue wires in the harness plug.

NEVER include the black wire when jumpering!!!
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If that connector is related to the transmission switch then I'm not sure of its relevance. I have the switch and it does function correctly.