LoveMy90JeepCherokeeXJ

First off, I am very sorry if this is the wrong place to post this.
I have a 1990 Cherokee XJ 4.OL 6 Cyl. My A/C /Heater isn't working. I have replaced the following without positive results: Blower motor, BM resistor, BM switch, and BM connector. When I turn it on it briefly works on High but then the fuse blows. I don't have Med or Low. Wiring to the switch is correct.
I should say that the Clutch MC has leaked into cab at the boot where the Clutch push rod connects into the fuse box. I've cleaned fuse box (without removing it) with electronic cleaner. No other fuses are blowing.
Further, the only ground I can find is the one located at the rear of the engine block connecting to the firewall.
I am at a complete loss. Please help. Thank you in advance.

BlueRidgeMark

This is the correct place.

The grounds are everywhere! They are hiding. I don't have a manual for the '90, or I'd look it up for you. I think you are wise to look at them, though.

Since it's a '90, it's what's known as a "Renix" Jeep. Chrysler completely revamped the electrical system with the 91 model year.

The Man With The Info on Renix Jeeps is Cruiser54. You may find the location of your grounds on his website.

It's odd, very odd, that you don't have medium or low even though you have replaced the resistor and switch. Very odd.


One thought - could the fan be rubbing on something?

LoveMy90JeepCherokeeXJ

I have the manual, had AllData, and currently have a CD with the 1990 Jeep Cherokee XJ manual but neither one shows the location of all the grounds. The only one that is shown is the ground from the rear of the engine block to the firewall. Unless, of course, I am missing something?
Also, in my original post I stated that the Clutch push rod connects to the fuse box, obviously it connects to the Clutch pedal and the CMC boot is through the firewall..Doh.
I have an AX15 5-Speed manual and thought (at least the info I looked up) shows the Renix as a completely different animal. Am I mistaken?
Just to be clear I am a blonde female greenhorn with doing mechanical-like stuffs on my Jeep... I've learned to work on it within the last 8 or 9 months by YouTube and these forums so when I ask if I'm mistaken I'm being serious and want to be set straight. I don't want to spend money on expensive Brake Dust or a Conniption Ring. Just kiddin' :-)

freegdr

See if fuse get extremely hot when on mine was doing similar thing from brake fluid eating plastic fuse box up. My cure was a fuse box trans plant.

BlueRidgeMark

Yes, ma'am! You are mistaken!

Renix can be either auto or stick. The term refers to the years a particular electrical system was in place. When Chrysler bought the Jeep line from AMC (American Motors Corp, now defunct), it very soon changed over the electrical system components to Chrysler stuff, rather than Renix stuff. That's the high-level gist of it, anyway.

So, nothing to do with auto versus stick.

I'm in love already!


You'll find lots of us very happy to help you.

But first, you need a decent manual. Also, check out Cruiser's tips on refreshing the C101 connector and connectors in general.

LoveMy90JeepCherokeeXJ

Sorry for the delayed response!
Lol😆 Thank you very much for setting me straight. The G101 connector I still need to replace. I did, however, replace the one ground I could see, which is the Radio Suppression Ground.
What manual do you suggest?
UPDATE: I now have A/C ....Yay! I do NOT have Max/High, but I DO have Normal/High. I barely have Normal/High, and an almost imperceptible Normal/Low. At this point, until I replace ALL grounds, I'm happy with what I have - especially since it was 103F the other day. Thank you so much for your help!

BlueRidgeMark

Uh, oh. Is that all you did? If so, that strongly suggests that you have grounding problems. That ground should not carry any appreciable current, normally. If you are grounding through that thing, somethin' ain't right, Lucy!

Please continue searching out and cleaning your grounds!



Nothing other than the Factory Service Manual (FSM).

There is a site which sells them, Pacific Coast Manuals. I have nothing good to say about them. Had some dealings with them and they went out of their way to be nasty about it.

freegdr

Read post no 1 here....http://comancheclub.com/topic/48852-...grade/....Also read cruiser book....http://cruiser54.com/

BlueRidgeMark

Ugh. That's a hack job. I do NOT recommend using any black oxide screw for grounding. Yes, that's what the factory does, and truth to tell, it's probably acceptable for DC circuits, but not a happy thing with anything radio.

Same with running two grounds. You can create something called a "ground loop". Again, not really an issue for DC, but definitely a problem for any radio or audio applications. It can act like an antenna to bring noise into the system.

After reading that thread, though, it does appear that Chrysler found that original ground to be less than wonderful, enough to change it radically. Still, I would simply replace it, rather than add to it like that.