Matts Jeep

Recently my '98 cherokkee had been showing that the battery only has nine amps but it continues to run. And if you turn it off and turn it on again it starts sometimes but not always. I had the alternater checked and it is still good and so is the battery. Does anybody know what would cause this???

Biohazed

check your wires .... Battery, Starter and Alt wires.

captainwoot

Voltage regulator is in the pcm, check wiring between alt/batt/pcm. Are your batt connections good?

Matts Jeep

Checks wires, harnesses, and had alternater check in a shop. still getting intermittent low charge. Bad alternater or PCM?

captainwoot

well if the alt checks out....i would guess pcm. you can check the alt, the 2 small wires, one will have 12v(batt voltage) the other is the one the pcm grounds to control output. You can ground this momentarily and check output. You can also eliminate the pcm and wire up an old school voltage regulator, if you don't mind a check engine lamp

tjwalker

Alternator is still in play here. The testing on an alternator is often not 100% conclusive. It is not unusual to have "escapes" (issues that testing doesn't catch) with that testing equipment.

Yes, the voltage regulator is in the computer, but for undervoltage, I still suspect the alternator.

But you should also FRESHEN all electrical grounds to be sure it isn't related to that.
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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.