T5 Top Cover Electrical Connector??

It's the Neutral Safety Switch. It tells the computer that the transmission is in neutral so that it is safe to do the engine running tests when the codes are being dumped.

If it is not connected correctly in an 86-93 Mustang, you will get a code 67 when you dump the codes.


Code 67 –
Revised 5 Jan 2012 to add warning of possible idle surge condition due to code 67

Cause of problem:
clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. External evidence from other sources claims that a code 67 can cause an idle surge condition. Do try to find and fix any issues with the switch and wiring if you get a code 67.

The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also checks to see that the transmission is in Neutral and the clutch depressed (T5, T56, Tremec 3550 & TKO)). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.

The following is for 5 speed cars only.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear. Jumper the safety pin to the ground near the computer.
Be sure to remove the jumper BEFORE attempting to drive the car!!!

It will do until you have a replacement. If you need to dump the engine running codes, you can always jumper it. Just don't forget to remove the jumper before driving the car...