CHEROKEE WON't START, Details inside, NEED HELP ASAP

[pryal7]

Thanks for helping... I have a 1997 Jeep Cherokee Sport 4.0 liter, 4x4. I just replaced the water pump. Vehicle started 3 times in a row, then I let jeep sit for 15 minutes while I cleaned up my garage. Tried to start it again and it did not do anything. The dash display comes on fine, but the engine (starter) does not turn over. Engine code 12 is stored now in the ECU. Code 12 says "Battery Voltage to PCM disconnected within last 50 key-on cycles." I have tested many circuits and this is what I have found... 12V is going to Starter Relay (Proper). When the ignition switch is in the start position, it IS sending 12V to the Starter Relay (Proper). The Starter Relay is for sure working properly. When the vehicle is completly off, and the keys are out of the ignition, the ground feed going to the starter relay, to complete the circuit, when the ignition switch is in the start position, the circuit is CLOSED. Problem is, when the ignition switch is in the ACC position or any other position EXCEPT the OFF position, the ground circuit going to the starter relay is OPEN (BROKEN, not a complete circuit). The wiring diagrams in the haynes manual does not show completely what is in between the starter relay ground and the ACTUAL grounding point, except for it does show that the transmission rang switch (park/neutral switch) is in between. DOES anyone know what is in between the starter relay ground feed and the actualy grounding point? Better yet, does anyone know what my problem is???? THANKS FOR THE HELP

[richard walters]

well i have a 1995 jeep cherokee that wont start but i have put a cps on it a coil on it and a cam - s on it and it still wont start iam not geting any fire and every one is tilling me it is the key switch so u mit have the same prob

[capt. apathy]

possably your neutral switch (only alows start in neutral and park), have you tried starting it in neutral instead of park.

just a quick easy check. if it starts in neutral change out the switch, if not check the switch anyway and keep digging.

[pryal7]

I have tried starting it in neautral, it does not start. And it does not start in any gear either, good thing. I got a little frustrated with it, so I decided to manually ground the starter relay. So it works now, but not really. If anyone still has suggestions, that would be greatly appreciated!

[bustedratchet]

When you say "ground" the starter relay do you jump the smaller starter wire with the big power wire. The small wire should have power in the crank position. A couple weeks ago I was checking a Jeep out wouldn't start in any gear and had no power to the small wire and it was the neutral saftey switch.

[pryal7]

Not sure how you are refering to what. One of the prongs on the starter relay is the ground wire, which goes from the starter relay, to the transmission range switch and then to the pcm. This is the wire that I manually grounded. When the key is in the "start" or "crank" position, that other wire IS sending 12v to the starter relay like it should.

[capt. apathy]

so if I understand you corectly, you made a direct ground, in effect wiring around the neutral safety switch, and this allowed it to start.

if thats the case it seems clear that either the switch is bad or a wire going to it.

[pryal7]

Yes that is exactly what I did. I thought maybe the transmission range switch (P or N) was bad also, but here is the weird thing. Without the key in the ignition, the starter relay ground ciruit is closed (the ground is working properly), when the key IS in the ignition and is in any position EXCEPT off, the ground is cut. So that leads me to believe that the Transmission range switch is working properly and the problem is the PCM. The ground from the starter relay does go through the transmission range switch, but it also goes through the PCM. Maybe when the PCM gets power, it cuts the ground or something. But I don;t know, do PCM's really ever go bad?

[capt. apathy]

my money would still be on the switch, I doubt it provides a direct ground path to the starter, it would seem more likely that it signals a relay.

I'd sugest removing your jumper ground, then unpluging the neutral switch and jumping past the switch directly at it's conection. if it starts like that you will know the switch is bad. if not you'll at least be 1 clue closer to an answer.

I'm not sure about the pcm, but I'd rule out the simple (and easy to fix) causes before I dug much deaper

[pryal7]

Good thinking, will definently do that. Only problem, I am not exatcly sure where the TRS (Transmission range switch) is? I'm not positive, but is it located on the passengar upper side of the tranny?

Thanks!!

[capt. apathy]

I'm not sure exactly(never had to change it on the jeep). I checked my haynes manual and couldn't find a location listed.

my guess would be either on the tranny or on the shift linkage. you should be able to find the color of wires in the wiring diagram and then check over the tranny and find a connection with that color of wire.

sorry I can't be more help than that, this manual has some huge holes in the information.

[bustedratchet]

I think it's on the drivers side. Follow the shift linkage back to the trans. You should see it under a pivot arm on the side.