2001 Merc Sable will not start. Wiring diagrams? Fuse box diagrams?

Question

So I got this 2001 mercury sable from a shady buy here pay here lot. It started fine and ran fine on my way to work. I tried to start it to leave, and it won't.

The idle position seemed to work fine, the lights come on in the dash, things start beeping, radio works. All seems fine except when I attempt to engage the starter, nothing. No sounds. Doesn't even try. I got the battery charged and no change. Rules out the battery and the alternator. So I pulled the starter, that works fine out of the car. I tried "jumping" the starter by using a screwdriver to bridge the control circuit and the hot and it works fine, but doesn't start the car. Rules out the starter.

Now I'm thinking the ignition switch is the culprit. So I attempted to hotwire the car. Not an easy thing to do. I tried all ways to connect the 4 wires that come from the ingnition switch. None seem to fire the starter. Furthermore no combination will make it start when I jump the starter. I'm still working on it, but I don't know if I will have any success.

How do I get the car to start? What other problems could there be? If anyone has insight into how I might bypass the ignition switch or the correct wiring diagrams for the car, I would be eternally grateful.

Answer 1

First off you need to put your ignition switch back together. The starting circuit is fairly simple for this car. It consists of the ignition switch, digital range switch (Assuming ATX), starter relay, the PCM, the starter and some fuses/fusible links.

Start at the relay (Relay 23 in the battery junction box) since it's the easiest part to check. Terminal 87 is always hot, terminal 85 is hot on start, terminal 86 is a PCM ground and terminal 30 is the path to the starter. For each terminal, if something is missing it'll point you in the right direction. If everything else checks out -Including the wiring- replace the relay.

Ignition Switch:

Back-probe the red/light blue wire coming out of the ignition switch and see if the switch is passing power. If it is, move on to the next component. If it isn't, check for power on the light green/violet wire. If that has power, replace the switch. If it doesn't, check fuse 107 (40A) in the battery junction box.

Range Switch:

Have a helper cycle the key to the start position with the transmission in park or neutral. Check for power on the input (brown/pink) wire. If it has power, check for power on the output (tan/red) wire wire. If the output wire has power, move on the to starter relay. If it doesn't replace the switch. If the input wire doesn't have power check fuse 237 (15A) in the under-dash fuse box.

PCM:

Key on Engine Off or Cranking the PCM should be grounding terminal 86 of the starter relay. If it isn't make sure the anti-theft system isn't active and check the wiring to make sure that there isn't an open circuit.