Jeep Thing

[pontiacgp]

My 2003 Grand Cherokee with the 4.7 developed a charging problem on my 40 minute drive to the office this morning. I notice the volts on the gauge dropped but no warning to check gauges lit up until the volts got into the red. On a pervious Jeep the warning came on as soon as the alternator died. I made it to my friend's business where he sells and installs stereos etc. I put the battery on charge and started the Jeep when the battery was at 60%. The alternator wasn't charging so I played with the 2 wires that plug onto the back of the alternator. The alternator started charging so I removed that connector and everything seemed to be clean and the wires were in good shape. I plugged the 2 wire connector back in and the alternator is charging like it should and even with moving the two wires around. With the rear defogger on, headlights on and ac on high at idle it's charging 13.4-.6. I had to top up one cell in the battery and the battery seems to be fine. I know alternators do not work intermittently and Jeeps are famous for electrical glitches so I'm wondering what I may be in for. The voltage regulator control on my Jeep is in the brain so I hope that isn't an issue but I did research a work around for that issue when my previous Jeep's alternator died just in case it wasn't the alternator.

I called the local alternator guy this morning and he has one for my Jeep but I don't want to buy it if I don't need it, what do you guys think?.....

 

[Bonnewagon]

I think jeeps suck. But you knew that.

I played with the 2 wires that plug onto the back of the alternator.

It is working now so I think the wiring is the problem. If twisting the external wiring doesn't affect it then it is possible the internal wiring is faulty. The connector plug wiring inside the case can get loose/cruddy and if you open it you can re-solder it for an easy fix. The "BATT" terminals on all brands are famous for breaking inside when people over-tighten the nut and twist the stud. Then the wire inside gets stressed or breaks.

 

[pontiacgp]

I think jeeps suck. But you knew that.

It is working now so I think the wiring is the problem. If twisting the external wiring doesn't affect it then it is possible the internal wiring is faulty. The connector plug wiring inside the case can get loose/cruddy and if you open it you can re-solder it for an easy fix. The "BATT" terminals on all brands are famous for breaking inside when people over-tighten the nut and twist the stud. Then the wire inside gets stressed or breaks.

thanks, I can shake the two wires and play with the plug and that does not affect charging. I did remove the battery wire connector and that was over tight and the stud did turn a bit removing the nut and after putting it back on playing with that connection has no affect on the charging. I just went out to start it and it still working fine....

 

[CaliWagon83]

Is the alternator that's in it original? Might be time for a new one anyway if that's the case. If you've gotten 150k+ miles out of it, then it's probably time.

 

[olds307 and 403]

Sounds like s dying alternator if connections are tight. Be thankful that POS 4.7 is going strong. A lot of them died early deaths.

 

[pontiacgp]

The alternator has a Delco sticker on it so it's not the original. I just did the 40 minute ride from the office and the alternator worked perfect. I think is was just the 2 wire coonector had a bad connection so I'll do the fix that Mark suggested.

 

[fleming442]

If you're not getting 14.4 between 1500-3000 rpm, it's toast.

 

[Max Headroom]

I bought a 1998 Jeep Cherokee for $200 one time. Guy started having trouble with the alternator not charging. Got tired of spending money on it and when it finally wouldn't run at all, he said he would take $200 for it. I asked a good friend who worked at the Jeep dealership to come look at it. When we got there he opened the hood and told me to go pay the guy. So I did. When I went back outside he asked if I had a hammer. I gave him one and he tapped the wiring harness connection on the fire wall and told me to crank it up. I turned the key and it cranked right up. He told me that the connection at the firewall gets loose and causes all different kinds of problems. When we got back to my place, he took a nut driver and tightened the connection. Put 6,000 miles on that car and sold it for $4,800 about 8 months later.

Worth looking at that connection, if its still there.

 

[olds307 and 403]

Check the connections at the ECM as well. I just remembered I lost charging twice after doing major work on it, leaning in the engine bay. I moved the ECM connector just enough to not charge. Push in the connectors, charging again. My Dakota will forget how to idle if the battery is low, old Dodge's are funny.

 

[pontiacgp]

the alternator is working like it should so I'm glad I was lucky enough to have the skill of moving wires around before buying another one. I was talking with a friend of my son who works at a Mercedes dealership and he told me the horror stories about the Mercedes electrical systems. They get cars in as new as 2019 that show a bunch of codes due to micro corrosion on the pins. The problem the dealerships have is they do not have the equipment to read the date cause it so fast. They have download the data and send it back to Germany where they have the equipment to figure out what the data is saying. The Mercedes now have barbs on their pins so they have a better connection so the micro corrosion doesn't cause the same issues. What I did with the 2 pin connection on my Jeep is what the Mercedes techs do, They recycle the connection meaning they unplug and plug it back in to see if that cures the issue, I guess I can consider myself to be a qualified Mercedes electrical tech now....

If I had bought a new alternator and just removed the old one I would have thought the old alternator was junk cause the new one worked when I recycled the 2 wire connector, I would have spent money for nothing and not even know it.....I thought I had another issue with my Jeep cause the check engine light went off yesterday afternoon but on my drive in this morning the check engine light came back on so I was relieved...