Help! Lost all power while driving -- no 12v keyed power

[firedog]

Ok. So here's what happened and here's what I know. I'm near my wits end, with a compressed timeline before we leave for Moab -- and I'm pulling my hair out. Here's the scenario.

Enjoying a nice sunny day, driving the 1990 GW down the road. BAM! motor dies, all power is out, gauges are out, I THINK I see a small white puff of smoke from the engine compartment. Tow it home. Here are some things I've done or that I know.

1.) I have constant 12v battery power at the fuse panel under the dash. i.e.) lights, hazards, etc.
2.) I have NO 12v keyed ignition power to the fuse panel under the dash, no keyed power to starter relay on the passenger side fender that goes to the starter solenoid.
3.) I "jumped" the starter solenoid, between the two posts, spun the solenoid, but didn't engage the flywheel or turn over the motor.
4.) I've checked every fuse I could find between the battery and the firewall -- didn't find any before the firewall.
5.) I've shaken wires while I had the key turned under the dash to see if a connection was loose, partially faulty, etc. no juice while doing that either.
6.) I've replaced the starter relay on the passenger fender with a brand new one
7.) There is connectivity between the starter relay ground and the neg post of the battery
8.) There isn't enough whiskey in my state to un-frustrate me in figuring this out...

Of course these things happen when I'm already packed up to my ears, leave in a month for our family retreat to Moab...and I'm starting to get a little panicky...

Any, all and mostly useful help greatly appreciated...

Cheers gang and thanks in advance!

Respectfully --

M

[rockrollin]

Fusable links connected to starter relay. Check for mushy spots.

[steveomd]

Bulkhead connector

If the 1990 model uses a bulkhead connector then unplug it at the firewall
clean it with spray can of electrical parts cleaner and reconnect.
If your model uses bulkhead connector sometimes these loose connection because of dirt and oil buildup.

[firedog]

Fusable links connected to starter relay. Check for mushy spots.

did a continuity test between the starter relay points and downstream of the fusible links by poking through the insulation...the fusible links seem good...?? grrrr what now?

[firedog]

If the 1990 model uses a bulkhead connector then unplug it at the firewall
clean it with spray can of electrical parts cleaner and reconnect.
If your model uses bulkhead connector sometimes these loose connection because of dirt and oil buildup.

I can not even freakin move those connectors....is there a trick or secret to getting them off?? they don't even budge for me...

[TexasJ10]

If the 90 is the same as my 81, the connector has a bolt in the middle you have to remove to separate the bulkhead connector.

I think you could have an ignition switch or switch connector issue. I'd check the connector on the side of the steering column first. The wiring diagram on oljeep should help you. http://oljeep.com/gw/elec/90_numeric...nSchematic.jpg

Your symptoms also sound a lot like what happens when the ignition module goes out. Typically no warning at all.

[firedog]

If the 90 is the same as my 81, the connector has a bolt in the middle you have to remove to separate the bulkhead connector.

I think you could have an ignition switch or switch connector issue. I'd check the connector on the side of the steering column first. The wiring diagram on oljeep should help you. http://oljeep.com/gw/elec/90_numeric...nSchematic.jpg

Your symptoms also sound a lot like what happens when the ignition module goes out. Typically no warning at all.

and by ingnition switch, do you mean the starter switch that is connected to the top/side of my steering column? I bought a new one this evening to install tomorrow...which switch connector are you referring to?

[rockrollin]

The ignition module wouldn't kill the guages. Ignition switch is a possibility, but I still suspect fusable link.

[acct21]

On a 1990, fuse #8 is ignition switched -- that feeds:
4x4 indicator lamp
Rear defogger switch
Overhead compass/temp
Keyless entry
Instrument cluster feed

If you lose keyed ignition power, you lose the instrument panel feed. Like I posted on your other thread, I'd start with the ignition switch -- assuming the fusible link going from the battery terminal on the starter relay to the ignition switch is intact.

[JeepJeepster]

Are those fusible links a one time deal? Pop and theyre dead? Never seen such.

[TexasJ10]

The ignition module wouldn't kill the guages. Ignition switch is a possibility, but I still suspect fusable link.

I missed the gauges being out in the original post. Probably not an ignition module in this case if the gauges are out. It sure seems like anything that killed the gauges would have taken out that #8 fuse as well.

I had the fusible link issue one time as well. The link itself was fine, but the crimp connection had become corroded under the tape and provided an intermittent connection. It was hard to find because you had to test it somewhere other than the actual connection. It took out all 12 volts not just the run side circuit when it happened to me.

The connector I am referring to simply the one that plugs into the ignition switch that you are replacing. You can see if you are getting "run" power at the switch and then check that it goes through the harness from that point to the relay.

[JeepJeepster]

I missed the gauges being out in the original post. Probably not an ignition module in this case if the gauges are out. It sure seems like anything that killed the gauges would have taken out that #8 fuse as well.

I had the fusible link issue one time as well. The link itself was fine, but the crimp connection had become corroded under the tape and provided an intermittent connection. It was hard to find because you had to test it somewhere other than the actual connection. It took out all 12 volts not just the run side circuit when it happened to me.

The connector I am referring to simply the one that plugs into the ignition switch that you are replacing. You can see if you are getting "run" power at the switch and then check that it goes through the harness from that point to the relay.

Thats one reason I was asking about the one time dead thing. Maybe it reads good with a multi meter but any sort of load kills it.

Battery terminals are bad for that also.

[rockrollin]

Usually when a fusable link goes, it's gone. The only times I've seen them burn out is when a direct ground has been contacted (bare hot wire). It is possible too I guess for one to still have a limited contact, that's why I like the mushy test. Most common one is going to the choke on the carb, it gets a lot of heat and the insulation at the end can shrink exposing the wire.

[Tripwire]

fusable link - as said squeeze the cables the entire length while pulling gently on them, the insulation is UBER high temp and when the link pops the insulation remains intact so visual is almost impossible

[firedog]

fusable link - as said squeeze the cables the entire length while pulling gently on them, the insulation is UBER high temp and when the link pops the insulation remains intact so visual is almost impossible

so not being super familiar with the fusible links...are they just in the oversized black portion of the wire...or are they the entire length of that green wire??