Hey guys,
This jeep were working on won't crank...it has power to the headlights/ tails, flashers work...but nothing on key actuation. Its an 89 4.0 i6 auto with like 270k on it.

So far we've tested the ignition switch (the key and pushrod), its hitting, the starter relay/solenoid (behind the battery) was my next guess but I can't make anything happen with it because I have no idea how to test it. I'm getting 12v to the wire coming off the battery, but no where else even with the key turned...ideas?

To fill in the story, we were riding along fine, then the passenger went to turn the heat on and it just died. Nothing would happen...we tried jumping the nss, nothing. So...any help?

 

I would start by disconnect all electric contacts in the engine area. Clean all contacts. Refresh ground contacts.

My 87 has power no crank no start fuel pump comes on.
The plugs by relays and coil did not have good contact. Cleaned them, dielectric grease and zip tied them tight and has been good for some time.

 

Most already are and we have power to headlights...wouldn't that denote we have grounds?

 

Not necessarily on the grounds. That's just the headlights. Power INTO the relay, but no power out any of the flat terminals?

 

I tried and I didn't get anything but I wasn't sure if I was and where/how much, I'm right next to it working on it now let me check them all with the key in the accessory/run position

Also a side note, battery tested ok, just to eliminate that possibility

 

I got. 3 volts out of the black and white wire I'm assuming comes from the ignition, but nothing anywhere else

 

x2 on grounding. Also check the neutral switch, try starting it with the transmission in nuetral, if it's a automatic.

 

#30 terminal, red wire should have battery voltage. There's a 4 wire connector near the passenger shock tower that the power flows through. Another connector behind and to teh rear of the battery. IIRC, it's six wires. Check them out.

 

I did, no power coming out if the relay behind the battery

 

How much voltage at the big threaded lug on the relay?

 

12 coming in

 

Have you checked for power thru fuseable links at starter relay

 

Yep. Next place to look.

 

I haven't seen one? Are we talking about from the pdc relay box or somewhere else?

 

Originally Posted by Firyls
showthread.php?p=245772145 - post245772145showthread.php?p=245772145 - post245772145
There should be a total of 4 ring terminals but 7 fusible links.

1. a. Blue = Alternator

2. a. Green = Ignition Switch
b. Orange = Fuel Pump Relay

3. a. Green = Fog Lamps/ Fuse Box / Engine Lamp
b. Green = ? (think it also goes to fuse box for other components)

4. a. Orange = B+ Latch Relay
b. Green = Fan Control Relay

Unfortunately the colors above only indicate the fusible link colors, I don't have what color wires they turn into after the fusible links end, and as they go to their respective destinations.

Since the its the green fusible link that's shares a ring terminal with an orange fusible link I feel that nails it down as the Ignition switch Fusible link. That fusible link at the very least needs to be replaced. That wire should go straight to the Ignition switch.

The fusible link colors indicate the Gauge.

Blue = 12 Gauge
Green = 18 Gauge
http://www.oreillyauto.com/site/c/de...5625/N0220.oap
Orange = 20 Gauge


You still need to find out cause it to go out. So doublecheck all the ignition switch wiring, replace the ignition switch (they're like 10 bucks). And check the fuses, mainly the fuses that control electronics power by the ignition switch. The fuses that are powered by the ignition switch are ABS Fuse, Power Windows Fuse, Clock Fuse, TCU Fuse, Gauges Fuse, Blower Fuse, Rear window wiper fuse, Turn/back up lamps fuse, and Radio Fuse.

If a previous owner jumper bypassed one of those fuses with a jumper wire or used a fuse with a higher rating, and then the component it controls shorted, that short could work its way back through the ignition switch and cause the ignition switch fusible link to die out.