1990 Ranger Dash Wiring

[steveoelo]

Does anyone know/have a pin out for a 1990 ranger? Need to know the input wire colour for the tach as well as the input for the temp, oil pressure and volt gauge. Looking at the wiring diagrams/posts here was kinda helpful but everyone seems a little unclear on the exact wires. Also, is the tach reading a 12v spike from the coil or does it recieve a signal from the ecu? Truck is a 2.9 with a 5 speed. Thanks

 

[adsm08]

At the cluster the wire colors you want are as follows:

Temp: Black/Light Blue to the sender.

Oil Pressure: White/Red to the sender.

Voltmeter: Receives input voltage from fuse 17, 15Amp, (most of these do) and grounds through a black wire. Said black wire also grounds the turn signal indicators. If you are having an issue that may help narrow it down.

Tach is controlled by a Dark Green and Yellow wire, and a Black and Yellow wire.

The wiring diagrams of how the tach actually works in this vehicle are a bit confusing. Generally in a distributor ignition system with a tach the coil gets a constant 12V, the tach gets a different 12V, and they share a pulsed ground, coming from either an ignition control module or a set of points. The diagrams for the 1990 2.9 are unclear on what's actually happening though. The page with the cluster on it shows the DG/Y wire coming in as if it were power to the tach and the tach having a constant ground, but the page with the igniton system seems to indicate the DG/Y wire is the ground for the coil.

 

[steveoelo]

Okay perfect, only reason I'm asking is because I'm in the middle of an ALH TDI into my 1990 and I'm trying to make it as close to factory (or at least what I think it should've been). For the oil pressure, does it go directly from the sensor on the side of the engine to the gauge or to the ECM, then the gauge? For the Tach, is it pin 4 on the ECM that goes to the cluster? Also does the engine coolant temp run directly to the ECM, then to the cluster or is it wired in directly like the Toyotas? For reference I'm using a Haynes manual and there isn't a clear 1990 2.9 diagram, just a 1989 diagram and a 1990 4.0 one.

 

[adsm08]

The oil pressure "gauge" is a dedicated wire to the cluster. Oil pressure hits 5 PSI, the pressure switch grounds the circuit, the needle pops to the middle of "Normal", that's is.

The temp system has two circuits. There is a 2-wire sensor going to the PCM directly, and there is a one wire switch that feeds only the cluster.

Pin 4 is the tach. Looking over the diagrams again I am wondering if the tach is wired in a parallell-series circuit to the coil. Doesn't make a lot of sense to do it that way, but I've seen Ford do dumber things.