I just aquired a 2011 314d and have no knowledge of previous owner or history. When I bought it the batteries were dead and it needed a boost to start. Barely had the juice to start the next time so I charged both batteries. Now when I connect the cable it sparks. I turned the battery disconnect switch off and there is a bigger spark when connecting the battery. Pulled out fuses one at a time and tried to connect the battery but same result. Someone hooked a wire to the positive side and one to negative side which goes to a box mounted in the battery compartment so I disconnected that but still sparks. There is an aftermarket emergency shutdown switch and another switch which looks like aftermarket that says cold weather start. Any ideas what to look for? Thanks
Try unhooking the cables at the battery disconnect switch. You may have a bad switch
I took the cable off and it still sparks on the battery.
The alternator is usually the only thing that is connected with the fuses pulled and switched off. It may get warm if you charge the batteries over night, that's a good sign it's bad. edit: wait, you have two batteries? are these hooked up parallel for a 12V system? then one of them has a bad cell if they spark with nothing hooked up.
2 twelve volt batteries. I took both out and had to charge them all day. Not Cat batteries but some cheap ones.
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Also machine will start with disconnect switch on or off.
Upon closer inspection I see the previous owner had the counter weight off. Maybe to work on the starter? Maybe someone made a boo boo wiring it.
All bets are off at that point. My condolences. Time to start at the beginning with a wiring diagram and remove anything that doesn't look original, or try to figure it out one wire at a time. To test the batteries, charge them up and then let them sit anywhere from a day to a week, they should have very similar voltage when you test them, 12.7 or so. One less than 12.5 is probably bad.
One aftermarket item says pre heat. I moved the switch and touched the cable to the battery and there was more spark than usual so it draws power when switch is on. The other aftermarket item is air shut off. Looking close at the engine I could see the starter looked untouched but a new water pump was installed.
Next thing I'll try is disconnecting the alternator. Maybe something shorting in there.
Send me a PM with your machine serial number and your email address and I'll send you an electrical schematic for it.
So that means either someone has bypassed the disconnect switch or the switch is bad
I took the disconnect switch out and tested it. Power goes through in either on or off position. Not always but if you push on the key or wiggle it the power comes through. I will replace it but being a ground wire I don't think this is the problem.
Of course it's the problem, if the disconnect doesn't, then something will draw power with it in the off position. That's what it's for.
My concern is that with the switch on when connecting the battery there is a spark. Is it all right to use the machine like this and as soon as I shut down turn the switch off? I thought there should be no draw from the battery even with switch on and key off.
I am not familiar with your machine, but just one small example would be the engine ECU, most CAT engines the ECU is connected directly to the battery and there is one wire from the key switch to tell it the key is on. It may not be much but the standby draw might be half an amp which would be plenty to give you a spark. Lots of other possibilities too. There may be a problem somewhere, first guess would be alternator, but they put the disconnect on exactly because something always draws a little power somewhere on modern equipment.
I just had a look at the schematic and the master switch cuts everything on the machine stone dead, even the ECMs (yes there are more than one). The OP has been in contact and I have his schematic ready for him, just waiting an email address to send it to.
I like what Lantraxco has to say and am giving Delmer's post about batteries more thought. To install 2 new batteries and new switch would be an easy fix. I only have an old style battery tester but all cells on one battery show half charge and the other all cells show between half and full. If I'm buying new batteries should I go with Cat batteries or is there an equal alternative?
Cat batteries are expensive but IMHO there are none better. I guess a lot depends on how you propose to use the machine. Do you have an electrical tester that will measure the resistance across the master switch so that you can see whether or not it's opening correctly. However the fact that there are apparently loads of aftermarket electrical add-ons (probably installed with no thought or knowledge of how the machine electrical system works) could be at the root of your problems.
Nige, I think you may be right about the aftermarket add-ons. With electrical problems it's usually best to try and disconnect anything non factory until you are sure everything is working properly, then add back one at a time, yeah? I've seen a lot of things wired around the disconnect for no real reason, people just seem to like the batter terminals for tapping power.
Thanks for the electrical schematics Nige. The emergency shut down is easily disconnected. Wired to the battery. Spark still there when disconnected. The preheat is located under the engine. On this gadget it says 24 volt, do not have on for more than 5 seconds otherwise solenoid damage can occur. I have yet to determine where it gets its power. Switch is behind the seat.
First I would put an electrical tester across the two terminals of the main disconnect switch P/N 7N0718. You'll find it on grid J13 of Page 2 of the schematic, not sure where it is exactly on your machine but generally is located fairly close to the batteries. Make sure that the switch goes open circuit when you turn it to the off position. These switches do have a habit of failing with the contacts permanently closed. Once you have established the switch is opening/closing correctly then carry on disconnecting your aftermarket accessories. Have you tried disconnecting/connecting the batteries with the main disconnect switch in the off position..?
I'm off to pick up parts today including the battery disconnect switch. Also picking up a new laptop as schematics are hard to see on this phone. The switch was letting power through in the off position.
Just talked with Cat service department and was told that with disconnect switch on there will be spark when connecting the battery post.
And they are absolutely correct in the case of your machine because there will be all sorts of "minor" current drains for things like the radio programming, clock, etc, etc. The only time you will not get a spark when connecting a battery is when the main disconnect switch is in the off position. However this will not be the case if the disconnect switch contacts are not opening correctly when it is in the off position.
Huge thank you to all you guys!