Hi terry, i have a jeep cherokee 4.0 4x4 my problem is i cant figure out whats wrong with the jeep it wont turn on,i just put on a brand new module and coil,tune-up and new starter and alternator and brand new optima battery once i put brand new battery it crank up sevetral times and now turn key nothing turns on not even radio,so can you help me please im clueless in texas,mechanic who put this on for me said there safety switch on transmission and had to move gear shift little bit back and forth then turn key and it start but tried that and nothing,i dont know what to do.please help.surfbandit!!!
Thinking we may have multiple issues here.
You said "now turn key nothing turns on not even radio" Nothing means nothing, not even the headlights????
There are fusible links (fuses) hooked up near the starter relay, the starter relay is the silver box near the battery. A good place to start looking. Best guess is you may have dirty or loose battery clamps, a failed fusible link or possibly a bad ignition switch. I tend to check the easy stuff first.
On the same starter relay (silver box near the battery), There are four wires on the 87 (five on the 88-90) Red wire is main power and if memory serves me correct it is marked (BAT) right next to the connector (threaded with nut). The dark green wire is usually the starter solenoid wire and is usually marked "S" next to the connector pole ( a spade connector). The green wire is from the ignition switch and is usually marked "I", the last wire is the neutral safety switch wire and is usually marked "G" likely black with a white strip.
The "G" stands for ground, all the neutral safety switch does is ground the starter relay so it can work. Easy test is to dsiconnect the black wire with the white strip and test it for continuity with an ohm meter (through the neutral safety switch, with the shifter in "P" and "N"). Then go to the pole "G" with the wire disconnected and test for power when somebody turns the ignition (key) to start.
There may be some differences in the markings on the face of the starter relay, different manufacturers sometimes mark them a little differently. The wire colors may also be off, 87 is a one off year and some of the wiring (and wire colors) are unique to that year. If the colors I gave you don't match up get back to me, I have an 87 harness and starter relay in my junk someplace and I can dig it out and look if need be.
Which fusible link goes to which sub system I've never been able to figure out. I know one is exclusive to the ignition switch and supplies most of the power to the switch. I usually test them all with a volt meter.