Ok, I was having high idle problems with my 99 Cherokee, changed the IAC with an $8 one off ebay.
Problems came back intermittently, guy at auto zone said maybe I had a bad connection and suggested dielectric grease. I had the bright idea to smear is across it across the plugs on the IAC, TPS, MAF... not thinking it might short everything out.

Jeep acted fine for awhile that day, then just started losing power, battery gauge would read fine with keys in but drop to nothing running with a check guages light. Broke down, kept getting jumps, but battery would not keep a charge. Had my brother meet me with starting fluid and sprayed out all the grease, jumped me, all was well, then replaced the IAC again with a spare I bought, idle is perfect.

Now yesterday, started up fine, but was losing power, stereo kept shutting off, windows rolled very slow while driving, classic alternator symptoms. Perhaps the alt is bad is just a coincidence. Is it possible to damage the alt by what I did? Started losing power bad it died, luckily close enough to home I had a neighbor tow me.

With the car hooked to another via jumpers runs fine, tested the alternator and was a little over 13 v. Tested it once more and was at 11v, but am suspicious it was because of a very low idle. Have alternator out, going to have it tested. Have a bad feeling it will test fine.

Now on to my question, I have been searching the net non stop and from everything I found people with this problem usually fix it because the alternator fuses are blown. Under my PDC, there are no 60 amp fuses or any alt. location for them on the PDC cover. However regardless of all this, it does appear to be classic alternator symptoms , like dying when jumpers are removed... If it is bad, I will probably just buy one off ebay for $70 dollars rather than pay more than double for one also made in china at auto zone.

 

i would also test the battery. not with a home meter, but at auto zone where they can load test it.

 

Forgot to mention, brand spankin new battery.

 

Sounds like loss of ground somewhere. Dielectric grease won't cause things to short, but to suffer from poor/no connection. When you successfully jumped the vehicle, I wonder if you hooked the negative clamp to the negative battery terminal, or to some portion of the block/body. The other vehicle might have been supplying the ground that yours is missing. I would start with the cleanup of all battery terminals, clamps, and ground locations.

A good alternator with poor ground will produce low voltage just as you have observed. Poor ground connections will also cause a bunch of other random things like you observed. Poor grounds will also lead to successful jumps but failure to run on its own.

Good luck! Keep us posted.

 

All jumping was just battery post to battery post. Just got back from the auto store, alternator is good. Ever since that event when things went screwy it ran fine all week. So perhaps it is a bad ground, and it is just a coincidence with everything else going on. Off to to some scotchbrighting on ground connections. Thanks so much for the replies. I learn to be a mechanic one problem at a time.

 

Could check the battery terminals too. I was having intermittent power problems. Found a hairline crack in my negative terminal causing it to not tighten properly.

 

All is well, put the alternator back in, got my scotchbright pads out and started cleaning all the grounds. The one in the back, the braided ground line where it connects to the engine was covered in oil and grime.

However I'm pretty sure it was the negative battery to body link. I tried to loosen the bolt, it was seized, everything in me was screaming just get the kroil oil, but I tried anyways and it just snapped off. So I just rigged it with one of those little screws, near the original on the passenger side that hold some sort of plate on with a washer. Will have to drill and tap a better setup but it works for now. Battery gauge is fine and reading right.

I just bought a house, so I will never sell the Cherokee, had it for so long and it's a great little beater, there is so much that needs to be done to it, new leaf springs next, it's sagging bad even with those auto part store braces. I like it mostly because I have a good sound system in it, no rap, just metal.

Actually only Christian metal now, as weird as that sounds. I married a Christian women, I being completely convinced the Bible was manufactured deception after all my studying, seeking truth from having some things happen in my life that let me know there was more to life than just the material. After witnessing a few too many coincidences regarding faith I said the following sincere yet skeptical prayer: "Jesus, if you are who you say you are, of course I would serve you, just show me something."

I while later my wife left for church me mocking and scoffing, I pulled out to go somewhere and as I was driving it was like the blinders fell off my eyes, a flood of info hit me, hard to describe, but I knew I was guilty and he was Lord as sure as if He as sitting in the passenger seat, I stopped in a rural area, got out and asked for forgiveness and was just engulfed in the most powerful feeling of love, I broke down thinking how could you love me so much when I'm going around telling everyone it's all BS. Found out she was praying for me at that exact time.

Sorry for the rant but I like to share that, as it says "Seek and you will find."

Thanks everyone. I'm sure I will be back here.

 

I see your problem is fixed. But for anyone searching for the alternator fuse, it's in the PDC, connecting the "Gen" and "Bat" terminals.

 

No. Dielectric grease is non-conductive. It's made for exactly the way you used it. That is not your problem.

It's also not a cleaner. If your connections are grungy, clean them with contact cleaner, then apply dielectric grease.

Dielectric grease will not cause a poor connection. It's made for exactly that purpose. It protects electrical connections from corrosion.

When connections are mated (whether push on or screw type) the grease is displaced at the actual contact points leaving a film that is only a few microns thick. It's enough to prevent corrosion but not enough to inhibit the flow of current.

That's why it's required in thousands of applications, including military, aviation, and space, where reliability is life or death.

 

Under my PDC front cover, it doesn't look like that diagram. Almost want to take a picture. It is just one bolt with the gen and bat connections stacked. Everywhere I looked on the net people with a similar issue were talking about two 60 amp fuses in the PDC with the other fuses. There is not one 60 amp fuse in mine, or any markings for an alternator fuse.

Thanks for the explanation of dielectric grease. I was thinking if the stuff does not conduct electricity, why would you want it near anything electrical, now I understand it does conduct, but only through an extremely thin layer.

I'm still perplexed why last week when my Jeep was acting up and I broke down after a few jumps from passerbys, I sprayed all the connections with starter fluid my brother brought with him where I had applied the grease to, it jumped and ran fine for a whole week. Makes me worry it might act up again and I have not found the problem, that it is intermittent.

 

I think your jeep may be equipped with a fusible link. It's essentially a section of smaller gauge wire somewhere along the alternator to pdc wire, designed to burn up before your pdc does if the alternator were to malfunction and start over charging.

That probably why you can't find a fuse. Someone chime in if I'm wrong.

 

A ground covered in grease and grime could be a good thing. The grease helps to prevent rust which when in a ground connection causes resistance.

I hope you in fact applied some electrical grease on all your newly cleaned grounds ... or you might soon find some newly created corrosion.

 

In all my military years servicing radar systems Dielectric Grease was only used where HIGH VOLTAGE was present and connectors were primarily plastic with silicone wiring insulation.

All other connections were made with MIL-SPEC multi-pin connectors that had waterproof seals to keep moisture out of the pin mating surfaces.

Dielectric grease automotive applications are generally used in the ignition circuitry..... i.e spark plug wires

Internal to a connector ---- dielectric grease is displaced by the contacts, the pressure between the two contact points displaces the grease. How it protects is the displaced grease is pushed to the outer edges of the contacts leaving a layer of grease along the edges of the contacts mating surfaces.

HOWEVER - If you have a BAD CONNECTOR where say the contacts have lost some of their spring strength - it might be possible for Dialectic grease to interfere. But to be clear it's not the grease that is bad .... it is a BAD CONNECTOR.


As you stated ......

Dielectric Grease DOES NOT ADD RESISTANCE in a connection ..... if it did there would be heat buildup and possible discolored wire insulation.

IMHO - Dielectric Grease is over used by auto enthusiasts ..... but better to over use than not use at all.


I am currently working on such an issue with XJ and ZY ignition lock/switch wiring harness connectors and have made some interesting discoveries. XJ owners are abusive to the electrical system of their vehicles. My guess is they improperly wire in accessories onto circuits causing near overload conditions. My evidence to this is burnt insulation on Pin 6 of that connectors in XJ's not evident on Pin 6 in ZJ's. Pin 6 carries IGNITION SWITCH OUTPUT ( ACC/RUN )

 

It's a common misunderstanding. If it were conductive, think if what fun you'd have after slobbering it all over a connector with multiple contacts!

But here's the dirty little secret - conductance (or insulation) is not an either/or thing. Most people think that there are insulators (never conduct electricity) and conductors (conducts electricity).

Actually, it's a sliding scale.

Almost any insulator will conduct under the right conditions. An "insulator" is just something that conducts so poorly that we don't usually think of it as a conductor. Dielectric grease is a very poor conductor (which means a good insulator) until you get it down to a few microns thick.



That might be it. I don't know which years had fusible links vs. actual fuses.


Jon, a failed fusible link can sometimes conduct enough to work intermittently, and they sometimes don't look burned at all. Look for a section of wire that is different from the other wire, with obvious splices. Pull on it and see what it does. It should not stretch.


Yes sir! Fresh clean metal just loves oxygen!

 

Since my alternator tested fine, I'm thinking my fusible link is good, unless something was causing excessive drain. I did find along the amp. wire from battery a 40 amp fuse in a rubber pouch that was working but all melted and distorted. I replaced it, hoping it was from when my last sub went out causing excessive current spike.

So perhaps I should check for the fusible link. Also, no I did not use any more dielectric grease on grounds. I was thinking, it is not like the sludge actually got between the tightened bolts, but I cleaned it anyway.