Re: troubleshooting 1996 Ford Ranger

On Sun, 12 Jun 2022 16:36:39 -0400, Clare Snyder <[email protected]>
wrote:

>I realize this forum is virtually dead but I am hoping there are still
>a fewe Ford Experts still monitoring.
>
>I have a 1996 Ford Ranger 4.0 5 speed longbox standard cab 2 wheel
>drive truck with no power windows. mirrors or locks. The speedometer
>has recently stopped working and I have found something that does NOT
>make any sense. with the ecu plug connected or disconnected and the
>engine-cab connector connected I get a DC voltage reading of about 8.5
>volts with the key off, rising to 12 volts with the engine running,
>and at the same time an AC voltage - cannot remember the base when not
>running, but rizing to 15+ volts with the engine running. When I
>disconnect the harness to the cab the voltage goes away. The speed
>censor gives me about 2.6 volts AC when spun by my Milwaukee battery
>drill and the signal can be read between pins 33 and 58 on the ecu -
>either connected or disconnected - as long as the cab harness is
>disconnected In the wiring diagrams the only thing these wires connect
>to in the cab are the speedo and the CTM / GEM. It would also connect
>to the speed controller amplifier/servo assembly if the truck had
>cruise control (which it does not) Pulling every fuse, one at a time,
>from the fuse panel in the end of the dash panel does NOT kill either
>the AC or DC voltage across the speed sensor. Is there any function or
>misfunction of the CTM/GEM on this vehicle that could/would feed
>either an AC oe DC voltave bact to the ECU/speed sensor circuit????
  In case there is anybody on here, I found the problem. There was a
short INSIDE the connector between the body/chassis harness and the
engine harness, shorting the 12 volts constant power from the ECU
Memory/horn fuse under the hood to the VSS signal wire - they are next
to each other in the connector. NO visible damage or indication.
Trust me, it was one HELL of a job tracing this one down!!!!!!!
Ended up cutting the vss wire from the plugs and adding an external
connection.