97 Grand Cherokee just quit

If you popped a 20 then something is wrong. Absolutly resist the urge to use a higher amp fuse.

The ASD relay is a simple circuit. It just cuts power to the ignition coil and injectors. Same design as the Fuel pump, Fog, AC, starter, and ABS relays.

Actually, the AC relay makes a handy spare for times when one of the more critical ones frags. And relays can blow. Although they usually show melty spots. They usually don't go bad enough to frag a fuse.

Yep. You need to get the service book. Somewhere out there on the internet is the pdf. Can't remember exactly where. At the end of this post are scans from my manual.

Should be a diagram printed on the relay itself

Take these with a grain of salt, they are for the 93ZJ which should be "close" to the 97

I'd be checking back to the injectors and between the fuse and relay. It is possible something shorted out in the relay center, there was a recall around your year for problems there.

Hope that helps.

Thanks for the information. it was greatly appreciated. Just to bring you up to date, here is what Ive done. Unplugged al the injectors Unplugged the ignition coil Disconnected the field coil on the alternator Swapped in the horn relay Still blows fuses when key is turned on.

Took a break Unplugged the PCM. Still have a short to ground.

Any idea where all the wires are connected together that go off to injectors, coil, altenator

Thanks Mike

Hmm. Did you ohm out the lines?

You need to use the Ohmmeter to determine what line is shorted out. Just swapping fuses in can damage other parts.

From what your telling me I'm starting to think there might be a fault in the relay center. Sometimes the connectors can melt. Take a look into it with a flashlight. You might have to take it off and look underneath to see if there are any burned spots. (needless to say have the battery out when doing this, it's too close to risk dropping a metal mount across.)

Your going to have to go through the schematics and trace things out. The splice A61/1 is located at the rear of the engine valve cover in the large black loom. Probably the most difficult spot to get at.

Should be an 18 gauge Dark Green wire with a Black stripe (that's what 18DGBK* stands for in the schematic)

Just a thought, but also look under the engine just back from the power steering pump. There is a bracket that holds the O2 sensor line. Sometimes the wire will melt at this location but that shouldn't cause the ASD fuse to blow.

Oh, and when putting the PCM connector back on, do it by pressing in then tightening the screw, don't use the screw to suck it in. The PCM body isn't strong enough to handle the force and can crack.

If you have a local dealer that works well with you, might stop by and ask to look at your model year schematics. (or maybe get a copy printed out). Depending on how hard the problem is to track down you might wind up having to pay the dealer to fix it. :/ I've had to do that a couple of times after beating my head against a rock.

First time was when I found out that a properly ohm tested coil doesn't necessarily mean the damn thing works. :) I consider that my $100 lesson.

I had the battery out and actually did take the bottom cover off the power distribution center.

I didnt look at it real close.

I would have suspected the ignition coil, altenator or the or the injectors but everything was disconnected when the fuse blew.

I'll take another look at the power distribution center tomorrow.

Thanks for the location of the wires and possible places to look for melted wires.

It got a little cold in the garage tonight so I gave up a little early. I really dont want to take this to the dealer but might have to.

Thanks again

Mike

BTW. The PCM connectors are just plug in/clips.

Unfortunately I had to concede (wife) and take my jeep into the dealer. According to the dealer, the wire to the oxygen center was laying across the catalytic converter. I had the exhaust system replaced a few weeks back and I guess they may have forgotten to secure the wire.

Thanks to everyone for your help.

Mike

Ouch! Send 'em the bill... There is *supposed* to be a DTC for that fault, but I suspect only in later vehicles.

I've already contacted them. I should here tomorrow whether they might reimburse me or not

Thanks Mike