Yea, not sure how to make it better. But, all the while I installed a 20amp fuse. With ac running car parked no issues for about 2 hours. Stepped on brake, turned signals, headlights, no issues. Went for drive and after about 7 mins noticed was not blowing cold anymore. Pulled over, popped hood and compressor clutch had stopped; fuse blown again.

 

I don't care what your certified cousin says, putting in a higher amperage fuse is not the answer. All that does is risk damage to something that supposed to be protected by it.

 

I agree, the circuit is designed with the fuse to blow with somewhat higher current than ought to be present, so if it is blowing, there is a fault

This fault can be traced, but you need a readable circuit diagram to do so

 

Downloads from the site take a few steps. Once you click on the desired manual, you'll see a circle with 3 dots near the upper left corner (ellipses). Click on it. You'll then see "Downloadable files", click on it. Then select PDF.





They don't have a 1991 or 1992 so 1993 should be close enough. The do share the same parts catalog.

 

I did download the FSM, and had a look.

The fuse numbers appear they may be different to those called out for a '91, so thats a bit confusing

All that you can do is try to identify what wire colors are running from the fuse, and disconnect them at the other end, one at a time, drive around for a while

A short in the harness is a high possibility

At the end of days, you can cut the wire near each end, and solder in a new splice

 

Thanks all. I did get the download for the 93. What I plan to do next to eliminate other possible situations is to put new fuse in and drive around but not turn ac on at all. I haven't even confirmed if the fuse would blow even without the ac on.

By "need a readable circuit diagram to do so" you mean the diagram downloaded?

Seems the fuse blows after driving for for about 7 miniutes or so. I can put new fuse in , turn car and ac on, not go anywhere and ac works fine. Once I drive around for a few miles, off it goes; 15A or 20A, don't matter.
By the way, would installing an inline fuse help at all?

 

2 things could be happening

1) something is getting hot after a while, and drawing too much current, this could be a switch, motor, connector, or wire

2) a wire has bad plastic, and a short happens somewhere in the harness with another chafed wire

All you can do is form a hypothesis, completely isolate that part or circuit until you find the culprit

This is why you need the circuit diagram, so you can trace each part, circuit, and wire color that comes from that fuse

You stated a fuse number and rating, but I could not find that in the FSM I downloaded, but I didnt look comprehensively, due to time constraints, but if you can find it and post it, myself and others can make suggestions

 

I'll hVe to look again, but I want to say its fuse number 6 in the 93 cherokee fsm. It's 15A and on the actual car's fuse block it's labeled as "ignition switch".

 

Ok, so on the fsm 93 cherokee page 1399 is the diagram I think is relevant. But I still can't identify the 15a fuse on the fuse block to trace it , or to determine what number it is. Maybe can get some guidance.

Just looking though, it seems the ignition coil or ignition switch is what's in question, which seems the wire follows some function to the ac, and some other items. I believe it interpahses with speedometer as well. I will mention that the gas gauge and speedometer work only intermittently....maybe issue is related. ?

 

Confirmed: ignition fuse is blowing even without ac running, but only after driving for a bit. On park, no issues. Don't understand why car starts just fine. I guess that fuse is not vital for ignition purposes. So, issue could be ignition switch or ignition coil im thinking.

Other thing to note, i drove car for half mile , pulled over to check, and fuse was already blown. Previously, it went further from what I could notice. Today is pretty hot compared to previous times. Maybe had to do with it.

 

Upon testing The 15A hazardous fuse, and it is not blown, the tester light does not come on at all whether ignition on or off. The 15A ignition test light comes on only with ignition on and the same goes for 10A auto tyranny fuse. All others come on whether ignition on or off. So, seems the hazardous lights (lamps) fuse holder there is a problem. And of course, hazardous lights don't work. Whether this is the root of my problem, I don't know.

 

Tried the suggestion to probe load side of fuse holder. All holders turn on, except hazardous lamps.

Removed all fuses except 15a ignition. Turned on ac and working. Went for drive and blew out again. I guess I expected that it would not blow then begin re-installing fuses one at a time until fuse blew again. I guess my thinking is wrong. I'm stumped.

 

I suspect the 91 and 93 may have different fuse designations

There will be a further breakdown of the circuits in the manual that allow you to trace better

Have you disconnected the A/C harness or wires ?

This is the next step, they should disconnected as close to the fuse if possible to eliminate harness issues, but near the components is ok, as it will eliminate them, be systematic

 

The fuse is blowing even with ac off. But i disconnected ac harness just to check, and it still blew.

What I discovered today is also that the fuse is blowing moments after i put it in drive and coast . I mean i barely crossed my street coasting, didnt even step on the gas, pulled over to check fuse and it already blown. If I put it in drive and step on brake, it's fine. Once i go a bit of distance is when it blows. I guess ill check gear selector functions/fuses see if related. Speedometer maybe? The speedometer works intermittently. Maybe related.

 

If the "instrument cluster" is on the same fuse, they are related.