97 Cherokee Country - Blows Fuse 11 on Start

[Jennifer-Adams]

I have a 1997 Jeep Cherokee Country (4.0L in-line 6) that I've owned for two years. My parents were the original owners and I'm the second owner. Over the past year and a half, I've had several problems with this Jeep but it is now a paperweight in the driveway.

The problem - it is blowing Fuse 11 (footwell fuse box, the "Run/Start Ignition" fuse) every time I attempt to start it. The fuse will blow when the ignition reaches the ON position (off/on/start).

It used to blow this fuse every time I would put it in reverse (as soon as the engine engaged the reverse position), and then would do it only occasionally, and then moved on to only doing it when it was in reverse and I gave it a goose to the accelerator, and then it simply stopped doing it altogether for at least the past 6 to 8 months - until now.

Over the past year or so, I've replaced:
- battery (1.5 years ago)
- crank position sensor (6 months ago)
- throttle position sensor (6 months ago)
- distributor cap (1 year ago)
- rotor button (1 year ago)
- spark plugs (1 year ago)
- starter (less than a month ago)

...plus a few other things that aren't related to the electrical/starting system (i.e., radiator hose, water pump, coolant temperature sensor, temp sensor pigtail, etc.).

We have checked the wires coming from the PDC and all connections are secure and wires look good with no fraying, wear, damage, or exposed wiring. We have also checked the wires coming from the O2 sensor and they also appear secure with no visible damage or wear, and they are not connecting to anything metal nor are there exposed sections of the wire wrap for the O2 wiring.

At this point, I'm guessing this is a wiring issue somewhere. Something is shorting out and causing this fuse to blow. Coincidentally, it was very rainy today when it started blowing the fuse (but it hadn't been driven yet, so there was no water splashing up into the engine compartment).

Any ideas or suggestions on where to start looking? Thanks so much.

 

[TerryMason]

Welcome to Jeepz.com
I think you're right that it's a wiring issue, but I don't have any real insight for you.

does your Jeep have more than one O2 sensor? I did some reading, and most people do blame the O2 sensors for this behavior.

 

[JPNinPA]

http://www.naxja.org/forum/showthread.php?t=1086814

 

[superj]

I would look at the wires at your neutral safety switch or your reverse light switch, on the transmission. Since it only did it when you put it in reverse, something around there is messed up and might have led to something getting fried since you kept driving it (understandably since you had to be places)

 

[Jennifer-Adams]

Thanks for the posts, and to answer/comment:

(1) I believe it was throwing an O2 sensor code at one point after I got it (the O2 sensor was replaced about 6 months before I got the Jeep, so it's now about 2.5 to 3 years old).

(1.a) Regarding the O2 sensor - sometimes (very infrequently) when starting, the Jeep would chug almost like a mild misfire for a few seconds. Pressing the accelerator (in PARK) after starting would usually clear up the chug issue, or turning it off and then restarting. Also, when it would do this, a gasoline smell was often present. (O2 sensor issue?)

(2) When it first started blowing Fuse 11 when I'd put it in reverse, it wouldn't do it every time, and the reverse lights would often not come on for a few seconds or not at all when backing up. This would likely confirm the suspicion that the problem may be in the reverse switch or somewhere along that route.

Someone had also mentioned the neutral safety switch, too. (Also, when it rains, it seems to do it more often, but nothing is getting wet unless it's leaking through the hood gaps because it'll blow the fuse before it has even been driven on a rainy day.)

Thanks for the comments...

 

[JPNinPA]

Thanks for the posts, and to answer/comment: (1) I believe it was throwing an O2 sensor code at one point after I got it (the O2 sensor was replaced about 6 months before I got the Jeep, so it's now about 2.5 to 3 years old). (1.a) Regarding the O2 sensor - sometimes (very infrequently) when starting, the Jeep would chug almost like a mild misfire for a few seconds. Pressing the accelerator (in PARK) after starting would usually clear up the chug issue, or turning it off and then restarting. Also, when it would do this, a gasoline smell was often present. (O2 sensor issue?) (2) When it first started blowing Fuse 11 when I'd put it in reverse, it wouldn't do it every time, and the reverse lights would often not come on for a few seconds or not at all when backing up. This would likely confirm the suspicion that the problem may be in the reverse switch or somewhere along that route. Someone had also mentioned the neutral safety switch, too. (Also, when it rains, it seems to do it more often, but nothing is getting wet unless it's leaking through the hood gaps because it'll blow the fuse before it has even been driven on a rainy day.) Thanks for the comments...

1a) Yes a pre cat O2 sensor can be slow and cause idle issues prior to reaching operating temp. Use only OEM sensors in jeeps. They are finicky that way.