[John Wood]

I have a 85 reliant se with efi and i bought the standard motor products part number SC5 speed senor replacement part. It doesnt look anything like whats under the car. Where the speedo cable gos into the axle theres a little rubber cylinder covering the rest of that part, is this the right place to look? then theres about a two inch section of wire coming out of the bottom of the cylinder that has been cut, or just rotted away. Is there a plug under that cylinder like the replacement part? The part is suppost to be a direct fit, but ive had multiple mechanics say its the wrong part. The little wiring harnesses that come with it i dont see anywhere they would go. I also dont see the rest of the wire for the speed sensor to go to the ecu i guess.

It sounds like they gave you a speed sensor for a non-cable, electronic speedometer. Your 85 is probably both; i.e. it has the tube for the output to the speedometer cable and the electronics for the PCM and cruise control. If the new piece has the tube for the speedometer cable, it could just be that the harness piece is just an adapter to go from the old connector style to the new connector style. You probably already know that the speed sensor is held in by a 10 mm head small bolt and that it seals with an O-ring. after the bolt comes out twisting and prying up on the sensor may be required and be prepared for some fluid to come out. i.e. have a pan on your chest if you are working from below in your driveway.

 

[ImperialCrown]

This is the correct part with the straight-through cable drive. Chrysler updated to the new style speed sensor and discontinued your large old style sensor.
The new style sensor should come with replacement wiring adapters as shown here. Maybe there has been wiring damage or modifications before you got it that may need splicing or repair in order to work?:

http://ns1.collectorcarsforsale.com/parts/SMPSTANDARD-SC5-Transmission-Speed-Sensor-For-Sale_190762045371.html

 

[willrappold]

Yea my car has both, but cruise control isnt on my car because i still have a speedomotor but its throwing fault code 15, i cant even find the old wire that it should hook up to like around the airbox or where ever it starts, so thats why i can say its not a loose wire, there is none. I can take a picture of it but i dont know how to upload it to put it on here though. :frusty:

 

[ImperialCrown]

Look for a Wt/Or wire and Bk wire for the speed sensor signal to the PCM connector. They may may be tucked out of the way or have been torn off. They should be in the wiring harness leading down to that area.

 

[willrappold]

can you be more specific, i gues you mean black and white wires, Where is the PCM connector? How would the wire travel once it left the speed sensor from the speedo cable, my wire leaves that area for about 2 inchs then its gone, dont see anything else.

 

[ImperialCrown]

I don't have the actual service manual that shows harness routing (probably near the oil pan and differential area) but yes, a White wire with an Orange stripe along with a Black wire go the the speed sensor from the PCM connector.
Your PCM (engine computer) should be in the left, front corner of the engine compartment. The wires travel between these 2 points.
Sometimes the spinning right inner axle boot clamp would catch a drooping speed sensor connector wire and tear it off, so you may have to look for them in the harness if this happened.