I have had starting problems over the last several months. Now the control panel does not even light up any more. I have installed a new battery, checked all the fuses, had the starter checked etc. I get 12.3V to the ignition switch and as soon as I turn the ignition on the power collapses to 0.5V. I have disconnected the control panel and it makes no difference. Then I unplugged the part of the ignition that I assume supplies power to components when the ignition is turned on and I get 12V on one of the pins supplying the disconnected plug. As soon as I reconnect the plug the power collapses, including the 12 V going to the ignition. I don't understand how a total collapse is possible with all the fuses staying intact. I had several people come and "fix" the problem, just to have it reappear. Is there some safety feature that would prevent the ignition from operating? A friend said that the left armrest where you enter the machine has to be in the "down position " for the ignition to work. However, I cant find any limit switch or any mechanism that would monitor the position of the armrest. I have been battling this problem for several weeks now and am at a total loss as I have no schematics concerning the ignition/starting circuit. Hopefully someone could lead me on the right path with this frustrating situation.
To boil it down, the positive battery cable connects to the big terminal on the starter solenoid, from there a heavy wire carries power to the key switch, possibly passing through a fuse, or circuit breaker, or a switch of some kind (I am not familiar with your particular machine). Somewhere in that circuit, from the battery positive post to the key switch is a broken or corroded connection, or a fuse that reads good, but is actually not. You have enough connection to let a meter read 12 volts, but as soon as the slightest load is connected to it, the resistance of the connection drops the voltage to near zero. Turn the switch on, start at the battery and read the voltage on the positive terminal, then the cable connector, then move to the starter solenoid, if you still have 12 volts there but not at the key switch, follow the wire up to or back from the key switch to the starter, somewhere there's a harness connector or fuse block, etc. where you will find 12 volts on one side and near zero on the other. Fix that. Good luck!
If you are using a DMM and not a Analog Meter you may help yourself by using a test light (probe style) in conjunction with (or even instead of) your DMM.... and be sure it is not a LED light tester.. The LED, as with the DMM do not draw enough amperage in the test to always show bad connections or false fuse readings.
Another thought. To simulate a bit of a load on the circuit while doing a "wiggle test" to try to find the loose or corroded connection. take the supply wire off switch and connect it to a head lamp bulb and ground the other terminal. This will put a load on the wiring that might just be enough to help you find the problem spot. May actually cause a dodgy connection get a bit warm to help find it. Also you say you have checked the fuses, but have you checked for power on both sides of the fuse when switch is in the "ON" position and the volts have dropped to 0.5 Volts? It may be rare but sometimes fuses that look good can have poor connections inside. And if you do still have a full 12.3 volts on both sides of the fuse with key on but only 0.5 volts at the switch at least you will have narrowed down where the problem is located, between the fuse and the key!
I want to thank all of you for your suggestions. I have made an error in my machine model it is not a model 3208 but a model 8032, mini exc. 3.2 t. Regardless the electric principals should be the same. All replies are pointing in the same direction and I did have an issue when checking the 50 A fuse that is inline directly from the battery. The other cable on the battery naturally goes straight to the starter. This 50 A fuse is encased into a nice tight looking plastic housing. Anyway, when I removed the fuse and checked for continuity there was none. Yes, I am using a DMM and even after scratching the fuse prongs with the leads of my meter I could not get a reading of zero resistance. Then I cleaned the fuse prongs with sand paper and the ignition lit up and the warning buzzer came on for one time until I switched to start position. Then it was all over again. The problem is that I am on an island in the republic of Panama and can't just run to Pep Boys to get a replacement fuse as it is fairly large and to get the housing is impossible. I even thought of bypassing the fuse with a # 10 wire as it should have about the same capacity, but I am worried to damage more components trying to solve the problem. Before anything I will check the voltage with the ignition in the on position. Again thanks to everybody.
G'day, Once had near identical problem. Was going to replace pretty new battery as considered it may have had internal short under load after having checked everything twice. Even though I had checked the battery terminal clamps several times prior and cleaned terminals and clamps (spotless) and tightened when I went to eventually replace battery I noticed an almost invisible fine split in the negative clamp - even though it provided apparent pressure on tightening it did not and just would not carry the current necessary for starting et al. You need cleanness plus clamp pressure. Don't know of course if that is yous specific problem but right track to look for 'break down' under load - it does not take much of a weakness to manifest a failure in one of the primary current supply lines. Best of luck, MX45.
for continuity (and most other tests) a DMM is a good tool. It just sometimes needs a helper when following the amperage path through voltage readings..... To be clear I have a question.. Did your fuse check zero for continuity or zero for resistance... If that fuse checked for no continuity that is where I would stay focused.
Sounds like the fuse itself is okay maybe, but the connection between the fuse and the contacts in the housing are intermittent. You might want to see if you can locate a 50 amp fuse of some kind with a substantial holder and wire it around the original fuse holder, leaving the orginal fuse out of the circuit of course. Or possibly a marine rated 50 amp circuit breaker that is resettable in place of the fuse.
The problem seems to be solved and it was not anything that I was chasing all these weeks. I purchased a 12V drop light with alligator clips. Connected the negative directly to the battery and got my positive from the ignition "ON" circuit. The light came on as did the lights on the control panel. The difference from all the other things I tried was that the negative came directly from the battery. At a closer inspection it became apparent that the cable from the negative to the "chassis" (for a lack of proper term) was well oxidized where it was exposed. In trying to find something positive about my trouble shooting with my head up my exhaust, I found a lot of future potential problems. The starter was mounted with one bolt only and not two, the wire to the starter solenoid was frayed and only about 10 leads were actually still connected, I found a useful tool when reinstalling the starter and looking for a bolt I dropped, a hydraulic hose was rubbing on the starter causing abrasion and a loose wire in a plug of the ignition. Most importantly, if someone says "I already did that", check it anyway. Thank you
It's easy to forget that there are to sides to an electrical circuit, the "hot" side(supply) and the "ground" side (return). This is where doing a voltage drop test can be helpful. In your case if you had connected from the negative terminal on the battery to the frame with no load on the system (key off) it would have read 0 volts on your DMM. Then when key was turned on and/or you tried to crank over the engine the meter would probably shown 12 volts indicating there was a 12 volt "drop". In most circuits anything over a few tents of a volt is reason to clean contacts or make other repairs. Here's a link to Fluke for more detailed voltage drop testing information: http://www.fluke.com/fluke/uses/comunidad/fluke-news-plus/articlecategories/electrical/diagnosevoltdrop
Another thing to consider is that each cell should have 2.2 volts, thus your 12 volt system is actually a 13.2 volt system.
Hello everybody, My digger 2013 JCB 8065 RTS being stored in the yard for few months. I tap wrong immobiliser PIN first time, so I tried again using right one. Once I turn ignition to start, as soon the crank been heard everything switched off and there is no sign of life in the dashboard anymore. The battery show 12.58V, and the fuses are not burnt out Any ideea what could be the issue? Thank you!