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HELP: Current draw from head lights...

A

AZRuss

NAXJA Forum User
I'm having battery drain issues on my 91 Limited and I think I've narrowed it down to something in the head light circuit. I'm hoping someone can tell me little more about this circuit and where I might look next.

Here are my readings:

Fuses pulled = (int) dome, hd lp dly, fl/pass (eng) ABS sys, HL Sys, Eng Cntrl
Current = 0mA

Insert ABS Sys
Current = 2.64 mA

Remove ABS Sys & insert Eng Cntrl
Current = 5.11 mA

Remove Eng Cntrl & insert HL Sys
Current = 0mA

Insert FL/Pass
Current = 59.6 mA

Remove FL/Pass & insert HD LP DLY
Current = 59.6 mA

Remove HL Sys (still leaving HD LP DLY)
Current = 59.4 mA

So, is the current draw from the Eng Cntrl & ABS Sys circuits normal (this XJ does have a factory alarm, BTW)? Also, is the draw from the FL/Pass and HD LP DLY indicating a problem with both the high beams as well as the delay circuit?

Any help is greatly appreciated,
Russ

BTW- yes, I did verify that the head lights are off and the high beams are not on. I also grounded the green/orange wire on the hatch to disable the factory alarm.
 
Both the Flash to pass, and HD DLY fuses feed the security system.

This is probably security system related.

There is a hood interlock/tamper switch for the security system. For some reason the hood switch draws 25mA(that what FSM says).

Is that what you are measuring?

Given that I have found some (electrical)errors and omissions in the FSM -- could it be that the 59 mA that you are measuring relates to the 25mA stated in the FSM.

Or maybe, the underhood light?
 
Hrmm, possible. I have been having problems with the alarm for some time. It has been randomly going off when nothing has triggered it. I was simply measuring the current draw from the battery (-) terminal to the grounding cable that attaches to it.

Do you know where the hood tamper switch is located?

I've been looking through my HL wiring harness as this problem all seems to have recently cropped up after I replaced my A/C compressor and installed an aftermarket trans oil cooler. When I installed the trans oil cooler, I had to push the wiring harness up out of the way a bit, but it is still has plenty of room/slack and is not pinched.

Thanks,
Russ
 
I believe it's located in front of the hood latch spring -- the one near the battery. That's mighty close to corrosive battery fumes.
 
Langer1, Not sure. I haven't let it totally die. I noticed the problem late last week when driving home. The more elec. accessories I turned on, the lower the voltage gauge dropped. I usually run half way between the 9v & 14v marks no matter what. Now, if the A/C or even the fan is on, I drop down, head lights, I drop down further, radio, further, etc...

I had the battery (optima red ~2.5 years old) and alternator checked and they both tested good.

Lou, I removed the hood switch and now I'm only getting a 40mA draw from the delay and flood/pass fuses.

Any other ideas?

Thanks,
Russ
 
Arg! I got those battery guage #s way off. I usually run half way between the tick above the red mark (11.5v?) and the 14v mark. It used to hold there without problem.

Now, with the interior fan, head lights, and radio on, I run really close to that tick mark now (~12v maybe?).

Thanks,
Russ
 
Have you done a load check on the alternator? If you've got the engine running and tha voltage is dropping sounds like a supply issue, not a reservoir issue to me. A weak alternator can hide as a weak battery until you replace the battery and have the same issues.....and then you're out 80 bucks.
Bob,
NAXJA Member #344
 
What do you mean by a load check on the alternator?

I did take the alternator off and over to Checker where they hooked it up inside their tester (a little electric motor & belt that attaches to the alt). It passed all their tests.

Thanks,
Russ
 
AZRuss said:
Langer1, Not sure. I haven't let it totally die. I noticed the problem late last week when driving home. The more elec. accessories I turned on, the lower the voltage gauge dropped. I usually run half way between the 9v & 14v marks no matter what. Now, if the A/C or even the fan is on, I drop down, head lights, I drop down further, radio, further, etc...

I had the battery (optima red ~2.5 years old) and alternator checked and they both tested good.

Lou, I removed the hood switch and now I'm only getting a 40mA draw from the delay and flood/pass fuses.

Any other ideas?

Thanks,
Russ
Click to expand...
Is the belt tight? I don’t see any problem with your numbers. Because your numbers are in MA “Milliamps” it thought you were looking for something that was draining your battery when it was parked over night.
 
Yep, belt's new, tight, & doesn't squeel. My fear is that the battery will be dead after a few nights (my wife doesn't drive it all the time). In one night it dropped about 0.5v, which seems excessive to me.

Thanks,
Russ
 
If the voltage regulator is in the alternator, is there anything else in the system that would cause such a voltage drop while driving? Eventhough the alternator tested good, I'm still suspecting that maybe it's bad.

Russ
 
AZRuss said:
If the voltage regulator is in the alternator, is there anything else in the system that would cause such a voltage drop while driving? Eventhough the alternator tested good, I'm still suspecting that maybe it's bad.

Russ
Click to expand...
Do this, everything off, check voltage at battery with multi-meter. Now run engine about 1500 rpm and read voltage again, next read voltage with everything turned on.

I have had Optima batteries check good but were bad; they just got hard to charge.

I had one 6 month's old go bad. It showed good with a load tester but in my jeep I had the same problem you are having. My battery charger in automatic mode kept telling me to check the battery, in manual mode it would charge. The dealer used one of those load testers on it and said it was good.

Finely I talked him into sending it back to optima for testing and they said it was bad.
 
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OK, now I just feel stupid. Following readings are from battery. 12.0v prior to start, 14.1 with engine on and no accessories. 14.2 with engine reved. 14.0 with A/C, radio & head lights. Battery guage is still dropping, but it looks like it's just the gauge.

Any idea what the guage is reading voltage across? I assumed it was the battery terminals, but obviously it's not or my guage is broken.

Although this makes be feel better about driving it, I'm still not sure why I'm losing 0.5v in 12 hours on the battery.

Russ
 
Another odd note: the battery was at 12.7v after I shut the car off. Now ~20 mins later it's at 12.2v. If I disconnect it, I'm up to 12.5v. Any idea what the steady state voltage should be once the car has settled down?

Russ
 
AZRuss said:
Another odd note: the battery was at 12.7v after I shut the car off. Now ~20 mins later it's at 12.2v. If I disconnect it, I'm up to 12.5v. Any idea what the steady state voltage should be once the car has settled down?

Russ
Click to expand...
11.5-12.2
 
OK, looks like my problem was more paranoia than anything else; however, I did find that the power antenna motor was constantly running. It was so dead that I could barely hear it, but sure enough, it drained the battery pretty low last night.

Anyhow, all looks good now except for the battery guage...
 
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Re: Problem solved... mostly...

So, I'll start a new thread with a more appropiate title for my new guage cluster question.
 
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