CherokeeChick33

So as i'm reading in the forums, it says that our XJ guages don't read too accurate when some changes are made. My boyfriend drives a 99 XJ and is into stereo systems. He ran a 320amp alternator recently and can't get the "check guages" light to come off.

I know there is a specific wire running off of the alternator that sends the signal to the cluster. Anyone have any idea what that wire looks like so we can properly disconnect it and run a digital read out?

Thanks ahead of time

Grandpaswagon

320 amp????

Do share a pic of that bad boy.

wjnfirearms

Higher amp custom alternators aren't a foreign concept for stereo enthusiats. If they are wired correctly, it shouldn't be an issue. There is also the possibility that the alternator is defective. It shouldn't be screwing up the factory gauges. I've installed higher amp units before without issue. You don't mention what the gauges are reading themselves, especially the voltage gauge. The "CHECK GAUGES" light should only come on if any of the gauges aren't reading in the normal range. If you disconnect the feed to any dash gauge, then the CG light will never stop lighting.

Where did he get the alternator from and was the unit designed for a Mopar application? If he used one for another vehicle app, this could be the crux of the problem. When I did the last install of this type, I used a custom unit from Pa Performance in Easton, Pa. They are on the net. The unit was specifically designed for the vehicle application I was modifying and worked like a charm. They market custom application alternators up to 1000 amps output. Their customer service and help are second to none.

CherokeeChick33

Pics will be up shortly..

We hooked up a capacitor to the lines running to where his amps should be and they're sitting at 15.1v. We got it from a company called MechMan who is known for stereo systems and as far as we know it is specifically made for his XJ. We have a buddy who thought that they only made 270s for our XJs and think he may be over loading but the dmm doesn't lie

When you turn on the jeep, it will read just fine. Then after driving under a load, it spikes and the CG light comes on and the guage spikes at 19. We are very confused but I guess he will just have to ignore the light huh?

Carl48

15.1 volts is beyond the acceptable voltage range per specs... so, you will get a light and probably also a trouble code. 19 volts is way too high...probably the result of the capacitor (you didn't mention the value) charging.