I have a 98 Jeep TJ with a plow. I put a brand new optima 750 cca battery last year. I didn’t use the Jeep for about a month in Sept and the battery was dead. After jumping it, it never got back to a full charge. Auto zone replaced it 3 weeks ago. I didn’t drive the Jeep for 5 days and now the new battery is dead also. I don’t know what is draining the battery. The plow switches are all off. Need help.
TJ battery draining when not in use
- Thread starter Ruffian1911
- Start date
You can disconnect the ground cable to alleviate that problem for long term storage OR you can troubleshoot to determine which circuit is drawing the battery down.
Disconnect the battery, select mA on the VO meter and place the meter leads between the battery cable clamp and the battery stud to measure the mA draw (normal should only be approximately 50-75 mA).
To determine which circuit is causing the problem; remove fuses from the PDC until the amp draw disappears.
Disconnect the battery, select mA on the VO meter and place the meter leads between the battery cable clamp and the battery stud to measure the mA draw (normal should only be approximately 50-75 mA).
To determine which circuit is causing the problem; remove fuses from the PDC until the amp draw disappears.
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After testing between negative terminal and cable, the draw is coming from fuse 17 under the hood which is for “Dome Lamp, Instrument Cluster, Data Link Connector, Radio, Courtesy Lamp, Underhood Lamp, Sound Bar Dome Lamp”. What is my next step?
Separate the items fed and determine which one of those are the offending component.
Is the under hood light staying on due to positioning of the mercury switch.
Is the under hood light staying on due to positioning of the mercury switch.
KennethS
TJ Enthusiast
Please don't take offense at this, but did you have the doors closed while performing this test?
Also, how much current did you measure with the ammeter? That may help rule out some things as the issue.
I did have the doors closed and no offense taken. Also the under hood light doesn’t work and I disconnected it anyway with no change. I measured 3.02 mA
3mA? That's like 2Ah in a month. I'm quite sure that's not your problem.
But the multi function switch on these go bad - it's the stalk that controls headlights, hazards, etc. Mine would intermittently light up the fog light dash light and drain the battery (I never measured the load but I'd assume about 150mA) . Could be that you have the same sort of intermittent issue - and the 3mA you measure is the "good" state.
But the multi function switch on these go bad - it's the stalk that controls headlights, hazards, etc. Mine would intermittently light up the fog light dash light and drain the battery (I never measured the load but I'd assume about 150mA) . Could be that you have the same sort of intermittent issue - and the 3mA you measure is the "good" state.
Puzzling one. Zef is correct, a 3.02mA draw shouldn't quickly drain your battery, very generally anything below 50 is normal. Not meaning to offend but are you sure you measured the draw correctly? All of those items you listed as powered via fuse 17 have power going to them constantly, they do not require the ignition to be on to allow current to flow. There should be a small draw there while those items are not on. Zef suggested a possible intermittent issue. Have you traced the wiring to those items to see if there is a break or short? You said the under hood light had quit working so you unplugged it, however, a short in the wire leading to the light connector may allow current to still flow. Next thing, could your new replacement battery be defective? When fully charged it should read in the area of 12.6 volts without the motor running, 14 volts with the motor running while being charged by a properly functioning alternator. Do you get those readings?
IF the tested circuit read 3.02 A; you have located the circuit and need to determine which component in that circuit is powered up while testing.
IF the circuit is actually drawing 3.02 mA; then you need to continue testing the other circuits since 3mA is a extremely minimal amp draw.
Have an assistant assist you in troubleshooting and start wiggling electrical harness wiring and connectors to duplicate the amp draw while testing.
IF the circuit is actually drawing 3.02 mA; then you need to continue testing the other circuits since 3mA is a extremely minimal amp draw.
Have an assistant assist you in troubleshooting and start wiggling electrical harness wiring and connectors to duplicate the amp draw while testing.
No offense intended, but take another look at your multi-meter. 3 mA is 0.003A or 3 thousandths of one ampere. In the automotive (or Jeep) world, that is nothing. 3A, on the other hand, is enough to drain your battery. Look for a light that is staying on or a problem with a radio. We had an old VW that tried to change the disk in the player until the battery died. Unplugged it, no more problem. The underhood light is a known culprit, due to the type of switch used. Radios all have a 'ghost' current used to keep the station memory alive, but it is usually very low current. Good luck in your search!
KennethS
TJ Enthusiast
It’s actually 3 one hundredths of an Amp, but yeah not enough to drain the battery.
My mistake. It is actually a .306 amp draw. I disconnected the radio and
it drops to .0002amps. What would cause the radio to draw that much when off?
it drops to .0002amps. What would cause the radio to draw that much when off?
FSM says .005-.035 amps is normal. You are well above that. Is the radio stock or aftermarket?
Is it wired properly? Usually they have a battery permanent wire and an ignition switched wire. Also, if it is hooked to an amp or remote wire check that circuit as well.
What !? I find it highly unlikely that any VW could have an electrical issue. Ask any German.
I had a similar issue with a Land Cruiser and the disc changer. There was a cd stuck in the changer that kept it spinning even when off. Bluetooth units can also constantly trying to connect if it’s older.
KennethS
TJ Enthusiast
What !? I find it highly unlikely that any VW could have an electrical issue. Ask any German.
Yeah, never has a VW back seat caught fire due to a battery short to the seat frame.
I know this and I’m not even a VW guy!!!