? about some wires/ update my battery dies when I turn on the heat or lights, Help

[jlewis]

I haven't had a chance to really look into the wires yet but I was just trying to get a head start before I work on it tomorrow. Under my oil pump on the engine there is a set of wires that plug into the engimne. What are those wires for? The reason I am asking is because I have been having problems keeping my battery charged. I have replaced the alternator and battery. When I was at Advanced auto they were trying to do a reading on my battery and alternater but it wasn't able to get a reading. When I noticed the wire set wasn't pushed all the way on it was then able to start reading the condition of my battery and alternater. When I was heading back from Charlottesville last night in the rain it my radio quit playing, lights on the dash went dim, winshield wipers were barely moving and my head lights went dim. When I got home I tryed to restart the engine and nothing happened. I am assuming that it was the reason my battery went dead but I was unable to look at because I didn't want to be late to work. Pretty much I was just wanting to know what those wires do?

I am also having a charging system problem. My truck won't keep a charge causing all my lights to go dim while I am driving.

Update 1/23/2010 6:50pm - I just found out that my battery voltage drops when I turn on either the heater or the head lights. Does anyone have any suggestions on where I need to check first?

[tgreese]

Can't help much without the year, model, equipment of your Jeep.

You may find the wiring diagram for your year/model at www.oljeep.com

[jlewis]

83 j10 360, sorry about that.

Can't help much without the year, model, equipment of your Jeep.

You may find the wiring diagram for your year/model at www.oljeep.com (http://www.oljeep.com)

[FSJ Guy]

There are several things in that vicinity.

There is the 2 prong plug that plugs into your alternator. But that's distinctly different than your engine block, so I doubt that is what you're referring to.

Then there is the oil PRESSURE choke switch. This is a two wire plug (with a big rubber boot, usually) that plugs into a round receptacle and prevents the choke from warming up if the ignition is turned ON and the engine is not running.

The only other wire down there that I can think of is the oil pressure sender wire. This is a single wire and plugs into the end of a round can. The round can is the oil pressure sender.

Normally, none of these should be causing battery problems without shorting something out first.

[letank]

Time to recheck the state of all those connectors at the alternator, a little contact cleaner can help a lot, even unpluging and repluging will give you an idea of how tight the contacts are for the molex connector, it can be a bit rusty, then the alternator big wire can be either loose or chaffed or melted by the proximity of the exhaust manifold. The resistor wire at the molex connector is your feedback for the charging/volt sensing.
Other point, do you still have the ammeter how was the reading when your battery was discharging?.... time for ammeter bypass: after you disconnect your battery connect both ammeter wires on the same ammeter post. Then install a voltmeter: get one of those $6 radioshack LED voltmeter and replace the test lead test terminal to anything practical to attach securely to a switch 12v (+) such as a free spot on the fuse holder and a good ground.

Added a pict:
http://picasaweb.google.com/jeepmr/FSJ#5429599133073837186

I am debbuging a similar problem on the 85 when the headlights are on and the engine speed is at idle or slightly above idle, otherwise it charges fine.

[FSJ freak]

IM from culpeper originally welcome:thumbsup:

[jlewis]

Thanks for your help I will be looking more into it tonight. Thanks.

IM from culpeper originally welcome:thumbsup:

[letank]

One more: the first easy thing is to disconnect and clean all the contact areas of the wires... rust/corrosion is not a conductor.... and may be first of first... is the alternator belt tight enough?

[jlewis]

Ok, I have looked underneath the truck and it has two red wires going into it. one is form the starter relay and the other one is towards the cab. The wires go into a male plug with two connectors which is located right across from where the oil sending unit is.

[letank]

Ok, I have looked underneath the truck and it has two red wires going into it. one is form the starter relay and the other one is towards the cab. The wires go into a male plug with two connectors which is located right across from where the oil sending unit is.
This is the electric choke switch, but I forgot (no clues) how it is connected, so a quick check here:

http://oljeep.com/gw/elec/GW_wiring.html

I do not think that it should be connected to the starter relay..... the schematic is not too clear for the 1983, but check the 85 year. If I look at my schematic from the Haynes, the power is coming from the same wire as the throttle solenoid (+) and going to the choke spade on the side of the choke. This wire is responsible for Jeep BBQ when it contact the engine creating a short.... so make sure that is is secured away from hot sources.

[jlewis]

Well I took the truck for a spin after cleaning one of the connections that I talked about. While I was on my drive, about 3 miles into it I started to loose my radio, and interior lights. When I got back to the house the interior lights were pretty dim. I then reved my engine and the lights got brighter. I am confused to the reason why I am having this problem. I have checked all wires and none of them are shorting out. I believe that it is some thing in the charging system that has gone bad but I don't know what it is. I am going to go check my brand new battery and alternator at Advanced Auto. I will be back to let you know if they have given me any advice.

[letank]

Well I took the truck for a spin after cleaning one of the connections that I talked about. While I was on my drive, about 3 miles into it I started to loose my radio, and interior lights. When I got back to the house the interior lights were pretty dim. I then reved my engine and the lights got brighter. I am confused to the reason why I am having this problem. I have checked all wires and none of them are shorting out. I believe that it is some thing in the charging system that has gone bad but I don't know what it is. I am going to go check my brand new battery and alternator at Advanced Auto. I will be back to let you know if they have given me any advice.

loose or corroded contact(s) at the alternator or bad battery cable (external and internal)

[jlewis]

Ok, I have narrowed it down to the head light switch and the heating control unit. Just so you know the radio does not effect the battery at all. I found it out to day when I was driving the I turned my head lights on and the voltage dropped. I turned my head lights off and the heater on and it just dropped as well. The radio doesn't effect the voltage at all. Does anyone have a idea of where I need to check first?

[letank]

Hummmm the headlight switch has a built in thermal fuse..... so may be there is a short in the light circuit.... it does not explain the heater issue... do you mean to activate the heater or the heater fan.

If it is the heater then you may have something loose behind the dashboard... remember to disconnect the battery before you fiddle w anything behind the dash.... those ammeter wires are really a BBQ waiting to happen. May be is time to bypass the ammeter....

IF the thermal fuse is (was) activated.. you have 3 circuits to check, the courtesy lights, the parking lights, the headlights. When I had issues w my thermal fuse..... not knowing better at that time, I dumped the switch and used 2 separate switches, one for the parking lights and one for the headlights so I could turn the headlights and not the parking lights.... and dumped the courtesy lights.... In my case there was a short in one of the front grille mounted parking lights.

[FSJ Guy]

Check the 2 orange wires that go from the ignition switch (the one under the dash on top of the steering column) to the heater fuse.

Mine got fried, I replaced it and then my alternator "magically" improved and no longer dropped voltage when I turned on the heater or the headlights or the turn signals.

[jlewis]

Thanks for everyone's help but it was a grounding issue. I would of never of thought about that.