89 mustang 5.0 speed sensor hookup questions

That looks like the car was AOD and swapped to T5. Might want to check what computer is in it before you hook up the wires or o2 sensors. The computer is behind the passenger kick panel. Take a pic of the label on it and we can let you know what you have.

The sensor/electrical connector in pic 2 is for the cruise control. Looks like the hold down bracket for the speedo cable is not sitting right as well.

That's a 92 to 93 5 speed computer. It'll work. The o2 sensor harness should run down from the passenger side down by the fuel lines, across above rack and pinion. There should be a connector by the sway bar mount on the passenger side....two more connectors towards back of k member ( 1 each side ).

That connector is for cruise control at the transmission. I don't think the computer uses it to see speed. ( can't remember ).

That two pronged sensor is the reverse switch. Without that the reverse lights won't work. Those two black wire might be tapped into the reverse light circuit.

That " U " shaped bracket is supposed to be on that black piece at the end of the cable. The wires for the speed sensor and the reverse switch come through a grommet in the trans tunnel. Exactly where those wires are cut.

OK, few things:

This car may have been AOD/T5 swapped as someone else mentioned - easiest thing to do in that case is to just grab a T-5 Harness (LMR makes repros for $99, but you can score a decently clean used one on eBay for $50-75). I'd do this first.

Some things you'll want to do if you grab the T-5 harness:
- DISCONNECT THE BATTERY (the T-5 Harness/O-2 harness combo can fry your ECM if you mix and match incorrectly) then swap out the T5 harness
- With the battery still disconnected, remove the PCM. Reconnect the battery and turn key on. Check for voltage on Pin 46 on the harness side of the 60-pin ECM connector - there should be NONE. Have a friend turn the key as if to start the car, you should still have ZERO volts Youre checking harness side, no computer attached. If you have any voltage to Pin 46 with key on/start, you'll need to change the loop on the O2 harness.
- IF PIN 46 HAS VOLTAGE: Find the O2 harness connection into the main harness. The stock location for this is passenger side frame rail, under the mass air meter. If you're completely lost, trace from the O2 sensors or the low oil sensor on the driver side of the oil pan. At this connection, you'll see a pigtail - it's an 8 pin connector, 7 are used (two for each O2 Sensor, 2 are 'looped', 1 for the low oil and 1 empty/unused). The answer for you is in the 1 unused and two looped pins - See the attached picture for how the 'loop' should be pinned FOR A T5 1989 MODEL YEAR W/ A MANUAL ECM (The two TEAL pins should be looped, Purple are untouched, the single white/empty pin is the unused one)

Random reference info:
The T-5 Harness has 4 plugs:
1. A single 8 pin connector - This goes through the trans tunnel and connects behind the driver side kick plate. You can trace the current harness to make things easier.
2. A 2 pin connector with [Orange/Yellow] and [Dark Green/White] wire - This is the speed sensor. Speed sensors are the same between T5/AOD, only the gear is different.
3. A 2 pin connector with [Black/White] and [Light Blue/Yellow] wire - this is the neutral sensing switch (NSS). If it's a world class T5, the sensor will be on the top of the trans case in the front (near the bellhousing) slightly on the driver side.
4. A 4 pin connector with [Red/Light Blue], [Purple/Orange] and [Black/Pink] wire - this is the reverse plug. There's actually a pigtail you'll need between the T5 harness and the connector on the side of the trans (your 5th picture shows the reverse sensor in the trans). On T5 models, the [Red/Light Blue] wire is looped, and the other two wires are for the taillights.