Changing Electrical Speedo Wire?
03-12-2007, 01:19 PM
#1
corner carver
Thread Starter
Join Date: Oct 2006
Location: New England
Posts: 4,371
Changing Electrical Speedo Wire?
My speedo works but sometimes jumps around the speed I am going. If I go 30, it will jump around, but sticks around 30 mph. I replaced my cluster with the Simco cluster and I replaced my speedo sensor. The only thing I could thing to replace now is the wire coming from my speedo sensor.
How could I replace this?
Would it be easy?
How could I replace this?
Would it be easy?
03-14-2007, 12:11 PM
#5
2nd Gear Member
Join Date: Jan 2007
Location:
Posts: 353
RE: Changing Electrical Speedo Wire?
It would not be all that easy if you wanted it to look original, you would have to completely undo the wiring protectors, and run a whole new wire. I would first inspect the wire casing under the car and see if there is noticeable damage in a spot. That is the only place I can see there being a problem with the wire. I believe, but am not sure that your wire goes from the speed sensor to the PCM then PCM to instrument cluster. So i would test it in two ways:
1. Test the wire from the VSS(vehicle speed sensor) to PCM, by running a new wire from the VSS to PCM. Doesn't have to be put in anywhere (i.e. just take the shifter bezel off and run it through there to the PCM), just make sure that it wont touch an exhaust or accidentally get shorted. Then go drive the car around and see if it still does it. If it works perfectly then put that wire in permanently.
2. Test the wire from the PCM to the cluster. Same as above, just connect it from one place to the other to see if that is the problem.
It is important that you don't do both test at the same time. Otherwise you won't know which is the faulty wire and you may replace more wire than you need. Also if you don't have a Haynes or Chilton's Manuel, get one. They have the wiring diagrams for your car which can be very helpful if you are chasing a wire!
1. Test the wire from the VSS(vehicle speed sensor) to PCM, by running a new wire from the VSS to PCM. Doesn't have to be put in anywhere (i.e. just take the shifter bezel off and run it through there to the PCM), just make sure that it wont touch an exhaust or accidentally get shorted. Then go drive the car around and see if it still does it. If it works perfectly then put that wire in permanently.
2. Test the wire from the PCM to the cluster. Same as above, just connect it from one place to the other to see if that is the problem.
It is important that you don't do both test at the same time. Otherwise you won't know which is the faulty wire and you may replace more wire than you need. Also if you don't have a Haynes or Chilton's Manuel, get one. They have the wiring diagrams for your car which can be very helpful if you are chasing a wire!
03-14-2007, 12:19 PM
#6
2nd Gear Member
Join Date: Jan 2007
Location:
Posts: 353
RE: Changing Electrical Speedo Wire?
Also:
It was a long post but the point was don't replace the wires till you know their bad. That is why you would run the test with just the wires, before you do all the work of reruning them.
It was a long post but the point was don't replace the wires till you know their bad. That is why you would run the test with just the wires, before you do all the work of reruning them.
03-14-2007, 02:18 PM
#10
4th Gear Member
Join Date: Oct 2006
Location: Durham, NC
Posts: 1,541
RE: Changing Electrical Speedo Wire?
check your transmission fluid...my fathers explorer had the same problem and it was because the fluid in his tranny were messing up the sensors, dunno if the mustang works the same way...but its worth a try right?