Check gauges... Again

Hey guys,

99 cherokee, 4L. New mean green 200 amp alt, all new water pump, ac compressor, tensioner pulley, steering pump and belt (so all bearings are in great condition and no belt restrictions). All those replaced few months ago. Before replacing them, I saw "check gauges" light every couple months while driving for just few seconds, right after the light went off for another few months. I thought its because belt got a little loose and spun on the alt pulley. As months went by and after replacing the above mentioned parts, the "check gauges" become more frequent, and now, it occurs every day (I'm positive it's not related to parts replacement).

So, I turn the ignition on, but don't crank, the battery voltage gauge jumps a little over 12v (normal batt voltage). After cranking and engine starts, the batt voltage gauge sits still at 12-ish volts, rather than jumping at 14ish volts. After driving for few minutes, the voltage at the gauge drops at 9ish volts and "check gauges" light shows up. After driving for a while the gauge jumps back to 14ish volts or, if I stop and start right away, the gauge shows 14ish volts. Batt is good, measured in the morning before starting the engine, I have 12.5v (engine stopped) and 14.3v with engine running (alt charging)-so alt is also good. I measured the battery with engine running also when the gauge showed 9v and "check gauges" was on, it showed the same 14.3v, so it looks the issue is not with charging.

I suspect it's a relay or a a bad grounding due to the random occurrence of the issue, but have no idea where to start looking at. And definitely the belt has proper tension and doesn't slip. Any suggestion are definitely appreciated.

"Check gauges" means check your gauges, it's not a Check Engine Light (CEL) and won't throw a code. It means one of your gauges or sensors is wonky. I'd bet it's your voltmeter.

P.S. Wonky = gone south or needs to be "checked".

ParadiseXJ said:

"Check gauges" means check your gauges, it's not a Check Engine Light (CEL) and won't throw a code. It means one of your gauges or sensors is wonky. I'd bet it's your voltmeter.

P.S. Wonky = gone south or needs to be "checked".

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Lol, never implied it would be similar to a check engine. I would prefer to be though since it would make things much easier. Its just that I have no clue what could be the root of the problem. I thought it could be the voltmeter gauge (or some relay) but wanted to find out what other people think before starting to spend too much time into this issue.

And if it is indeed the gauge, should I get a new dashboard with all the gauges (well, new or working) or is it possible to replace just the voltmeter (or just get a voltmeter individual gauge to be installed independently of the factory one). Never messed with the factory gauges and have no clue... I would assume that the voltmeter gauge and the check gauges are interdependent, meaning a check gauges light would be followed with a low voltage reading and vice versa. Is this correct?

Thanks for answering!

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.

That's a good advice, always wanted to replace woven engine ground. Thanks for suggestions. I'll check/fix groundings then see if gauge shows 14+ all the time engine is on.

Thanks again guys.

The OEM volt meter is controlled off the CCDBUSS from the PCM. It is possible the cluster could be bad, but I'm betting on the PCM. Since you're saying it is charging at the correct voltage when the error occurs. Defiantly clean your grounds. If you have a buddy with a 97+ I would see if he'd let you borrow his cluster to eliminate, or confirm that is or isn't the issue before going through the expense of buying one.

I'll clean/replace the groundings in the weekend and post the results. Thank you very much for suggestions!

My apologies if I missed this, but did you UPGRADE your wiring when you installed the HO 200A alt? If not, sure that is a major part of the problem. You can burn your vehicle down without doing so. An inline fusible link is an excellent thing to install as well.

Johnnie Walker said:

My apologies if I missed this, but did you UPGRADE your wiring when you installed the HO 200A alt? If not, sure that is a major part of the problem. You can burn your vehicle down without doing so. An inline fusible link is an excellent thing to install as well.

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Yes and no. Yes because I run 2 batteries with lower gauge (thicker) wires. The batteries are located in the back of the front seats. They connect to a box with custom fuses. That box is placed under the hood where the original battery used to be. The + and - from batteries go to metal plates mounted on the box with 1/4 nuts. Old car wiring connects to the same metal plates through other 1/4 nuts. So old car wiring is the same, it just connects to the metal plates instead of connecting directly to battery in front. It goes like this: 2 batt with thick wires -> metal plate on the custom fuse box-> jeep original wires that were connected initially to battery. I'll take a pic when I get home, it may be a little confusing since I'm not very good in explaining.

When you say to update the wiring, you mean go with a better gauge from alt to batt? Do you think the alternator amp difference from stock (I think it's 130-ish amps) to mean green (200 amps) is too much for the stock wires? I'd appreciate some details when you have a chance.

Maybe I should've mentioned this batt conversion also, but before I did the 2 batt mod, and before I had the 200 amp alt, I saw the check gauges light on too, but not that often, this makes me lean towards a grounding issue at least, independent of the alt mod. Of course, it may be something else on top of this.

You mentioned an inline fuse, that is a pretty good idea and I'll do it. I have a related fuse question, if you don't mind (and if anybody else knows): is here any place you can think of that sells those high amps fuses? The highest I found is a little over 200 amps (which is good for the alternator) but I'd like to get one for my winch, right now it connects straight to the batt and I don't like it. Winch I think draws something like 450-470 amps.

Thanks for answering!

Update: today when I started the car I had the same symptom: voltmeter gauge stayed to 12-ish then dropped at 9-ish and check gauges light went on. Right at that moment I measured the battery with engine running:11.4 volts. So it seems that the mean green "state of the art" (as they call it, lol) voltage regulator took a plunge. It's still in warranty so that's not an issue. Of course, after 10 min of running, it started to charge back at 14.3... Stock alt that I replaced the mean green with till I get it fixed is a 90 amp, and the only one that I hear is better is a 120amp bosh (napa).

Once again, thanks a lot guys for your help!

FYI.. the voltage regulator is the PCM, its not internal in the alternator.

Digger87xj said:

FYI.. the voltage regulator is the PCM, its not internal in the alternator.

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Thanks, didn't know. I was referring to the alt diodes.

OEM Wiring between the 200 amp alternator and battery should have been upgraded to larger wire, and from the battery location to the old battery location should have been increased in size as well, all at a minimum.

Ecomike said:

OEM Wiring between the 200 amp alternator and battery should have been upgraded to larger wire, and from the battery location to the old battery location should have been increased in size as well, all at a minimum.

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I didn't change the 4 gauge wire between the alt and the battery, it's pretty short and should be ok. But the battery wires are ac gauge 4, which is probably 4-5 times over rated.