electrical grimlin on 05 TJ - Off-Road Forums & Discussion Groups

jeepjunky · #1 10-21-2009, 01:57 PM

HID headlights (with balasts) on and hit my rocklights (6-55w halogen...run with relays directly from battery) jeep sputtered and all electronics flashed off, came back on and was fine (gauges, heater, headlights, radio). Was at idle tried rocklights again and jeep died. The second time I noticed that my batt gauge dropped to about 10. But even when everything is ruuning it shows 14. With the headlights off, and turn on rocklights the heater fan boggs down for a second.
This sound like a bad Batt? or just too much draw on a single batt, and need to install a second batt?
Thanks

LEVE · #2 10-21-2009, 02:11 PM

First, Ground... Ground... Ground.

Then look at the voltage to the battery when the lights are turned on with a meter on the battery.

Jim_Lou · #3 10-21-2009, 02:14 PM

You're pulling about 30 amps with the rocklights alone. I don't think it's unreasonable for the battery to drop to 10 volts on that much draw. My guess is that what you're seeing is the huge load pulling system voltage down until the alternator can get its output back up. It may be a fault with the alternator regulator, which should be able to pick up quicker than that.

It could also be a weak battery or a weak connection, most likely at the battery or the solenoid where power is split to your lights and the rest of the system. Does the starter spin the engine easily, or does it crank slowly? You can check for weak connections by turning on the lights, engine off, to create the draw, and then measuring across every connection and each piece of cable with a voltmeter. That shows how much voltage drop is being created in that section. Anything more than a few hundredths of a volt is too much. And as LEVE says, don't forget the ground connections from the chassis back to the ground terminal.

You can also check the battery condition with the voltmeter by seeing how fast the battery voltage drops with that load. If the battery is strong, it will immediately drop to that 10-volt level when the lights come on, and then fall quite slowly from that point on. If it drops from 10 to 8 in a couple of minutes, it's getting weak.

LEVE · #4 10-21-2009, 02:17 PM

If there's a problem with the battery, or the alternator... then that would show up during starting the engine. If there's a question... take it to an autoparts store and use a load tester to see what's happening during start mode, run mode, and when the lights are flipped on.

jeepjunky · #5 10-21-2009, 08:47 PM

I plan on taking it to a autoparts store for a batt load test, but its been raining pretty good all day. Figured Id be nice.
It starts real easy not like a dead battery. I havnt checked my grounds lately, but each lite is grouunded at the light.
This is a new issue since installing the HID's. But they were a direct plug and play wireing system.
I tried it again tonight, and noticed that my gauges bottom out and the radio turns off.
I did get into the jeep without the rock lights and noticed that my raido clock was reading 12:00. usually this only happens when I disconnect the battery.
Ill let you know what I find after a battery test

GeeAea · #6 10-22-2009, 05:28 AM

There shouldn't be any regulator issue. Your alt is controlled by the PCM. It enables the field on and off. You have a battery temp sensor that adds to the mix there on how the PCM reacts to load.

jeepjunky · #7 10-22-2009, 08:11 PM

The results as of so far, Battery tested good and the Alt showed -4.3a draw when fully loaded....so By that time for a heavy duty alt. But wait, a new grimlin appeared! when I went to start it this am it was dead, but on the second attempt to start it did so with out issue?!? When I did the battery and alt check at the parts store, it wouldnt react the way it did yesterday?!? I went to pickup some parts and went to start it afterwards and it was totaly dead, I had to wait several seconds before the gagues flashed then it started without issue?!?! Got home and started looking for loose wires and all were tight BUT 1, it was the power lead on the battery to the aux fuse box, this piggy backed onto the pos terminal of the batt. After tightening this there hasnt been an issue at all.
Before I call this a victory, Im gonna wait untill the storm passes and run a second load test to see if the problem is fixed or just passified.
Ill keep you informed. and thanks for the help

Jim_Lou · #8 10-23-2009, 10:08 AM

You have a bad connection somewhere.