mattdel

hello! i own a 2000 Jeep cherokee sport with 84k miles 3 inch rough country lift. I recently went on a trip from Delaware to Vermont and got caught in a snow storm on the way (the entire way), nearly 3/4 into the trip I seemed to have power fluctuations very shortly which then disappeared. The trip totaled nearly 11 hours at pretty low speeds, the next morning my battery was dead and i eventually realized it was because the light controlled by a mercury switch under the hood fell of its mount during the drive which im not sure is related to anything other than killing the battery..once I got the jeep jumped we took a drive up to Maine at which time I started having my guages jumping around and shorting out all the while my battery was pinned. I also observed that i lost my low gear and had to resort to using my manual 1.2 and 3 which seemed to work fine which seemed to coincide with my abs light and occasionally my check gauges light. eventually once it got warmed up the problem disappeared even the drive home was smooth. a couple days later more gauge cluster issues and abs light trans issues. brought it to shop it was throwing codes at least two codes for the speed sensor and another for the alternator which was replaced at least 2 weeks before the trip. mechanic had me buy 170 dollar sensor seeing as i had a new alt and the sensor changed nothing. he asked me to take it to the previous mech who installed the alternator which I did and he after looking over everything extensively relays fuses connections etc decided I may need a new computer so I got one for a ton of cash...so here is the deal with all his electrical equip attached to the car he deduced that the dash was only receiving 9 volts and asking for more which was shorting the system sucking power from the alt (which also got replace again under warranty), that was with the old comp with the new comp it was getting like 19 volts! I dont really understand the issue as well as I should I feel because its electrical based and all the obvious things have been ruled out. 3 weeks no jeep please help (i also would like to add that if i baby the gas pedal i wont get the short once I give to much power abs light trans loses atleast 1st...mechanic is trying going through the harnesses next to find the short) TPS cps and nss seem to be fine

97grand4.0

pff. dude. First off find a new mechanic(s).
Any chance there is something leaking under the hood, such as coolant from a radiator hose, power steering, ..spraying the alternator? That will wreak havoc with the alternator then disappear once it dries out.
Second, take it to advance or autozone for a free charging system check.

mattdel

mattdel

i thought it may have been the mechanics doing but at this point its running on such low rpms I def dont want to drive it and wear out the trans..my only option would be to have it towed to a dealership or possibly do more research on good mechanics in the area....this guy now is a jeep guy he buys and works on lots of them which is one of the reasons I went to him. When i left the first mechanic he had unplugged the alt for me because he thought that was the reason for the issue and since the shop i was going to wasnt far he said I would make it, turns out that he just didnt test it enough and it existed regardless of the alternator so 4 miles into the 5 mile drive of me pushing it a little to be sure it finally tripped lost low gears abs and check gauges light and drained the battery i almost didnt make it

97grand4.0

Sorry but I would have to back out at this point just too hard to diagnose without seeing it or more info.

tjwalker

You have a lot of symptoms, and it's hard to tell what may be causing what and if there is more than one root cause.

1. First of all, post any and all codes that you currently are seeing. Not just a description, but the exact codes. With OBD, the devil is in the details.

2. Next off, maybe one of your mechanics or you did this but if not, it has to be done immediately. I didn't see any mention of it. Freshen all engine grounds. You can get a lot of "gremlins" if the electrical grounds aren't solid. More on grounds below.

3. Don't trust your gauge for this one. Get a multimeter and place one lead on each of the battery posts. At an idle, you should be seeing approximately 14.4 volts, give or take a smidge. What are you currently seeing for voltage?
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

jordan96xj

Follow tjwalker advice. The very first thing to do is to clean up all your under-hood electrical connections, including all of the grounding connections. Poor grounds and connections can also lead to the computer seeing "low voltage" which will cause it to command the alternator to produce maximum voltage. Which is why poor connections can sometimes lead to high system voltage readings.

This NEEDS to be done before swapping any more parts.

https://www.youtube.com/watch?v=iaysQluwch0

mattdel

I told him several times that he should check the grounds and make sure all connctions were clean so im assuming he did so. im hoping at least, today he said that when he disconnects the trans wiring harness and steps on the gas he gets no issue when trying to cause the short but when he connects it and revs it gets tripped so he said its either the wires or trans solenoids but he isnt sure....he removed the harness and claims that he cant find any thing....he wants me to buy solenoids.....what do i do