What could be draining my battery when the vehicle is not running? I noticed the dome stays on constantly. I can jump start it and it runs. But last night when I turned off the engine, then shut the headlights off, the head lights started to come back on, but very dimly. I know it sounds like a ghost story, but could a bad head light switch be my culprit. By the way, it is an 86 XJ.
Thanks, Greg
When I turn the head lights on, the dome goes off, when I turn off the head lights, the dome goes on. Bad switch?
Sure sounds like it to me.
Chris
Yes, it could be worn out.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
I pulled the switch out and realized the plastic plug that interfaces with the switch at some point melted. So I put it back together, and had to jump start the Jeep. It started, but when I removed the Jumper cables from the battery, the engine immediately quit. Why would it do that?
Greg
Well you have located your problem. The switch must also be just as melted as the plug.
I have cut those plugs apart and put individual new spade connectors onto the wires to mate up with the new switch. Either that or a junk yard crawl is in order looking for a new harness pigtail.
If your battery is 'really' low, the engine computer shuts off.
Continual draining of an older battery can actually kill it.
Mike
The switch is not melted at all. My question is, why when I put it back in, jump started the vehicle it started. When I removed the jumper cable, the engine stalled.
Greg
Well it must be the battery is shot. It starts fine with a jump. I thought it was the switch somehow.
Thanks alot. Greg
You can always just unplug the switch to make sure it isn't shorting.
And 'if' the plug got hot enough to melt, 100% for sure the switch is damaged. Your symptoms prove that.
Mike
Could be, judging from later posts. But I'll bet your domes aren't going all the way out when you turn on the headlights, they just get dimmer because amperage is going to the relatively lower resistance path through the headlamps.
Be thorough and test it both ways before you spend the money. Jump it with the switch in place and with it disconnected and see if it stalls both ways. If you start repairing things and it doesn't work right you won't know if it is being caused by a faulty replacement part (bad-out-of-the-box happens way more frequently than it should), something wrong with your repair work or some other problem.
Broken top post on your battery? I've had the post come off a battery before and it did exactly what your saying. Didn't notice till I went to clean the terminal and the darn thing came off with the battery cable.
Man, thanks for all the advice, I am trying to sell this thing today, and this is really the only thing wrong with it. I just went and bought a new switch, and am going to put a different battery in this afternoon. The guy is coming over at 6 o'clock. Hope this works. Thanks again everyone.
Greg
Check the pins out in the plug's socket!!!!
If rotted from heat, they will fast wreck the new switch...
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
Thanks.
Greg
When you jumper from another vehicle it starts? When you remove the jumper from the other vehicle it stops? Your voltage is too low and your computer shut the engine off.
As noted, could be a short in the switch, whether or not it is melted.
Get a cheap voltmeter.
Thats what was happening. Finally got this all fiqured out. Thanks alot!!
Greg
But why would the engine stall because of a faulty headlight switch?
Greg
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