No prior electrical problems but now the starter (key) switch produces nothing. Turning the ignition on lights the dash lights and the fan and other accessories work. I can engage the starter by jumping the high-amperage solenoid located just inside the engine door and putting +24v to the white-red wire (running to the starter solenoid) on the same unit. So the starter and it's interconnecting wiring is all functional. If I could find a wiring diagram showing the basic pieces and wire colors of the starter circuit I could trouble shoot it much easier. Anyone have a service manual handy, or at a minimum can describe what I should see (i.e., measure) happening at the solenoid when the key is turned to start? I also find it odd the heavy red wire which is ultimately switched to the white-red on the small side of the solenoid has no juice in it...so even if the solenoid did engage, it has no _24v to send to the starter. I have a feeling the lack of +24 at the red wire is part of my problem.
24 volts? Don't catch it on fire or melt the harness mate. It's a 12 volt system. Did you say there is no power at the main wire at the starter. Should be 12V all the time. Get a multimeter and check both ends for a start :drinkup
yes, 24v No question it is 24 volts; (2) 12v batteries in series. It's a grey market machine, isuzu diesel, if it matters.... There is battery power to the starter solenoid, and it'll crank if I jumper the solenoids. Problem is the solenoid has 1/2 dozen low-amperage inputs going to it, so I need to know what to test for to see why the key switch is not activating it.
If your unit is the same as the larger Hitachi I believe you are describing what they call a safety relay. It prevents the starter from engaging if the engine is already running. Also it disconnects the starter once the engine starts. It does this by a signal from the alternator. The regulator in the alt. can fail a diode and and the voltage leak will make the safety relay prevent the starter from working. There should be only two wires from the main harness that activate the safety relay. One will be the signal from the key switch. The other will be the signal from the alternator. you can test it with a light or a volt meter. Also be aware that there could be two fuses (fusible links) usually at the electric battery disconnect. One is live with the key off the other is live with the key on.
still looking my starting problem likely resides in the starter safety relay - I really need a wiring diagram to trouble shoot. Does anyone have a scan of the starter electrical diagram for any similar sized hitachi EXxx? This is a mid-90's machine w/the isuzu diesel engine. there was an ex200 starter diagram posted here earlier but too fuzzy of an image to read.
Try this it is for an ex100 hope this helps!
thanks -3Doc thanks for the ex100 diagram....the basic components and # of wire connections & their letters at each component look equal to mine...from memory anyways. I'll compare it to the machine tonight. Kind of curious what's meant by the "load damp relay"? It looks like it's purpose is to keep the battery relay energized (via a signal from the alternator) if the engine is still running even if the key switch is turned to off?
You are right that is exactly what it does, then as soon as the engine stops it "dumps" the load on the electrical system.
did you ever figure it out? Looks like I have the same problem with the same model excavator. Did you ever figure out what was wrong?
I have the same problem with the same model. What was the solution?
fix In my case the starter solenoid was burnt out. It took me a while to figure out how it got damaged. Here's what I found (with the help of the above ex100 diagram which is close enough for the ex60urg): - The excavator hadn't been used for a while and the ignition lock had started to seize - I started the engine and drove away, not realizing that the key was stuck in the START position, it hadn't returned to RUN by itself - There's a circuit (safety relay, see machine's post above) that cuts off the starter once the engine (alternator) is running but in my case the alternator belt had come so loose the alternator didn't spin and therefore didn't cut the starter - I drove the excavator for 20 mins and during that time the starter motor must have been running and the solenoid was engaged the whole time which caused it to burn out and seize I got a new starter off ebay (~ $150 iirc) and managed to put it in without dropping the engine but it was still a pita. And yes, I replaced and tightened the belt (batteries are charging now, nice). And lubed the ignition lock. Btw, big thanks :thumbsup to everybody who posted information on this thread. It allowed me to fix the ex myself for cheap instead of paying big money to have someone come out and repair it.
Thanks Maxa, I think my problem has something to do with the safety relay. I have a boat with Hino diesel engines and had a similar problem and it was the safety relay. Ironically my alt is not charging and I need get that addressed too. Wish it was just the belt but I think it is something more serious. Regards, Chuck
Hi i have ex100-2 that doesnt turn off with the key any ideas? if i turn it off then unplug the alternator it will stop. or if i cut the blue-yellow wire it will stop can i just wire the blue-yellow straight to alterntor waring light chhers for any help
hi there I know this is an old topic but I have an ex60 with nissin engine, it is not charging, light goes out on dash when engine is started but less than 24volts at battery, also when you switch off ignition, lights are still on dash and buzzer sounds!? and the large contactor next to the batteries is still energized but if I pull the T shaped plug with two wires out the back of the alternator this cuts the power to contactor and all lights and buzzer go off as they should, is this an alternator fault or does this machine have the load damp relay as wiring diagram above?? thanks for any help that can be given.. Tom.
Hi Tom I Have almost an identical problem on my EX60 except the alternator light doesn't work at all. Have you fixed It yet.... cheers Dave
not yet Dave, going to have a look at it today will let you know what I find.. cheers Tom..
Hi Guys, I might be able to help you. I was not here when this thread was posted but the guys got most of it right trying to work out there problems. The diagram above is very fuzzy and hard to see things but i have worked most of it out. The wording is miss leading but what ever. Why the (load damp relay) its actual function it to maintain a connection from the output of the alternator to the battery's at all times the engine is running as the alternator can be damaged if run with no output. The Safety relay primary function is a starter relay with start inhibit function if the engine is running. So this is where it gets tricky and is that diagram exactly the way your machines are wired. For example typically the alternator warning light is used to excite the alternator to get it up and running each time the engine is started. In that circuit shown there is no warning light and the alternator is excited using a resister shown on the back of the alternator near the plug. In this circuit the Safety Relay, Load Damp Relay, and CPU are sensing the excitation voltage from the alternator and presumably the cpu is controlling the alt warning light in the cluster. The only part of the circuit i haven't figured out is the stop function from the key. With Regards to tomD machine I would guess your alternator is fine. What you are describing all of the relays are doing what they are supposed to be doing. Am i to assume the engine does not stop when you turn the key off?? Regarding the charging my first look would be at a loose fan belt as the alternator can create the right voltage to trick all the relays but still not delivering current to the battery's to lift the voltage. Secondly i would check the fuse-able link marked 30b at the battery relay. Your machine will start and run normally but will not charge your batterys if that has failed With regards Davids machine I think you are not so lucky. In a conventional wired alternator if the light does not come on and the bulb and wiring is good it is usually the brushes worn out in your alternator, only minor repair. If it is like diagram above the cpu controls the light. Are all of your other functions in the cluster working correctly? is your machine charging? you need to provide all details. Cheers and good luck.
Thanks for your reply been working on it today and think I have a few problems the bulb had gone in the cluster so fixed that. but still wont charge. And sometimes you need to tap the safety relay to get it to start. Could the safety relay effect the charging. If I were to excite the alternator which terminal would I use? Also one other thing that is a bit odd the automatic revving only works on the tracking not the boom? Thanks Dave
Hi Dave, I can explain in detail how that relay works if you wish but the short answer is possible but not likely. The only way it would interfere with the alternator is if the electronic side of that relay were damaged and shorting the sensing wire to ground. This would not allow the alternator to excite. The more likely cause of needing to tap it is there is large inrush of current on that relay which means the contacts need cleaning if you can get it apart without breaking it. Another possibility is a bad earth connection at that relay. Its actually a good ideal to try to excite your alt manually because it is also doing some very basic checks which will give you an idea how your alternator is. if you make up a couple of wires with a bulb holder to take a small 24V bulb like in the cluster 2-3watts. I can only go by the diagram unless you take a picture and post it. pull the plug with (small wires only) off the alternator and remove what is shown on the diagram as a link between B the output lug and the S terminal wire WB. Wire your bulb temporary between B the output terminal and the terminal shown as R where the LY wire was. Turn your ignition to the on position, the battery relay should be on and power from the battery should be present at the output terminal of the alternator. If the bulb is glowing this is good but if it is not you have probably got worn out brushes or your regulator is faulty. If the bulb is glowing start the engine and bring the revs up off idle and if the bulb has gone out you alternator has started. If the bulb is still glowing with the alternator running you have more serious issues in your alternator. If you have a multimeter i can step you through further tests. Cheers
Thanks I've done as suggested and no joy. So have take the alternator apart cleaned the armature and hey presto it now charges and fixed the buzzer problem to. Thanks so much for your help. gonna start looking at the auto idle now today. It works on the tracking but not the main hydraulics? Every thing else works okay. Thanks Again Dave
Hi Back again, Ex60 wont start on the key now... has been an intermittent problem for a while and then stopped completely so thought it was the pre starter safety solenoid so replaced the switch part as I cant find a complete unit with the electronic part and still no good I'm guessing its the electronic part as I've tested the 4 pins 1 Earth 2 ignition live and 3 switch live from key. not sure about pin 4 guess it comes live when it starts. (forgot to test) Any ideas on the fault or where I can get a new unit or would it be okay to drive the solenoid direct from pin 3 or would I need to put a relay in? thanks Dave
Hi Dave, I would not drive the solenoid on the starter direct from the key if it was me. Since you have not posted a picture all i have to go on is that earlier posted circuit diagram which has 5 wires on the safety relay. So you have to tell me what your numbers are represented on the diagram and why a missing wire??. Is this relay mounted directly on the starter? Have you have checked that your ignition switch is sending out 24v in the start position and appearing at the safety relay on pin S (BW wire)?? The start position only sends power to that relay and a glow plug timer from what i can see. If you can solder i can tell you how to modify the existing relay to remove the electronics or you can just go and buy a standard $10 relay and retrofit it. Off course it will be just like any car, if your dumb and turn the key to the start position when running you will get a grinding noise from starter. Do you hear any clicking noise when you try to start at the safety relay or the solenoid on the starter??. The way you are describing the wires is very confusing. You should only have power appearing at pin B when the key is turned on. Power appears at pin S when you turn your key to the start position. If the engine is not running power is passed trough the relay and appears at pin C and continues through the loom to energize the starter solenoid. When the engine starts approx 24V will appear at pin R. Pin E is earth or machine frame. Use a small bulb or a multi meter to test each step. Get someone to turn the key for you so you can listen for safety relay clicking or starter solenoid clicking. Another thing worth checking is your fuses as they can become intermittent cause they can have hairline cracks in them. That diagram could be a simplified diagram because i see very few wires on the fuse box but they are indicating current draw across the top of ignition switch on each circuit. Shows a 10A on start circuit so may be corresponding 10A fuse?? Regards.
This thread is good. I have a ex60 with charging and starting trouble. For over 3 years the customer would unhook a battery cable because it wouldn't charge the battery. Now he wants to fix it. I replaced the alt with a aftermarket one that was 300.00 cheaper than a John Deere. It only charges at 25 volts and Batts wont stay charged. Nothing electrical worked before. No running lights no idiot lights. So no charging idiot light ether. We put two good battery's and it started but want start again untill you unhooked a battery cable. We here a clunk when we take the ground off. Then I put a cleaned ground back on then it started but won't start untill unhooking ground again. I thank it is the safety solenoid that stops the starter from working when engine is running. There are three inside the door on the Right side. Which one is the starter safety solenoid.
Hi chiefcw2, You might have to get someone to help you to find the clicking safety relay. Just a note: 25V is probably not charging at all but just the standing voltage of the batterys. Looking for around 28V. You need to do some quick checks as you might burn out that new alternator you have fitted. I know this is going to sound strange but an alternator MUST have a load and if it output is open circuit from the battery it overheats internally. Your machine has a solenoid which does just that and isolates the alternator from the battery with the key off. For that alternator to operate battery voltage must appear on its output terminal when you turn the key on. Also some voltage (can vary) must appear on the LY wire. This is provided by a resistor from the output terminal and some from the warning light so is not full 24V. This trickle of a voltage is used by the alternator to excite its self and get up and away charging when the engine starts. Your starting problem is almost certainly the start safety relay is faulty or wired wrong causing it to think the engine is running. Good Luck.
Mr 007, I was glad you saw this. Can you tell me in the batt. Compartment on the right side, from top to bottom what the name. Of each solenoid and a short definition. I am not sure which one is safety solenoid. I can fill the one in the middle click when the key is turned on. And I can fill it when I take the negative cable off it's terminal. Otherwise it won't start two times in a row if I don't take the cable off. Does John Deere have the solenoid and how much are they?
No Clue never seen your machine before. Maybe someone with a manual might save the day for us. The wire color code in the posted diagram would be a clue also. a lot of machines have the safety relay mounted out on the side of the starter solenoid. You could post some pics, you never know i might see some thing that might help. If your machine is as per that diagram there should be only the battery relay in the top left corner being energized when you turn the key to the on position. no other relay should click unless you crank the engine or the engine starts The cost of what? you keep saying solenoid for some reason. If you mean Safety starter relay I read a thread where the guy said a new starter safety relay was $150 i think. I personally would be fitting a $5 dollar relay and losing that other starter inhibit feature. If you mean Battery Relay it will be a fare size item with large cables attached and prob cost will be eye watering if you went genuine. I don't believe it has any issues as the engine would not start if that was not closing. Can you confirm its the relay with the large cables on it that is clicking with the key on please.
I call it a solenoid because they look like a solenoid to me. Your right on the battery relay it is larger than the other two relays and all three are on the right side of the battery compartment. I can fill the battery relay click, when the switch key turned on. But it don't click again when the key is turned off. It looks to me it's the safety relay like you said I don't know how to identify the safety relay.
Thats interesting thanks. Based on what you have said odds are there is nothing wrong with the relays. The starter saftey relay and the load damp relay both monitor the alternator light circuit to determine if it is spinning. If it is spinning there will be a voltage present there which in the case of the safety relay stops you engaging the starter and in the case of the load damp relay it turns on and locks on the battery relay which is not disabling when you turn the key off. This means both relays are doing as they should. This means ether the alternator is faulty, or has been wired wrong, or someone has done some wiring changes and some how has ignition being applied to that circuit. That circuit is what they call a latching circuit because once enabled it locks on until the engine stops. Now you know where the battery relay is follow the small wires from it to find the load damp relay. The diagram indicates a terminal with two small wires connected, maybe green colour. One goes to the ignition and the other the load damp relay. Then you have two out of three relays identified. If you find the load damp relay and find terminal 1 and see if 24v appears there when you turn the key on. If it is there then thats a problem and you have to find out where its coming from.
Mr 007, Thanks for your help with the ex 60 it is 30 miles away and I have been adding to my barn so I haven't been back to the machine. I will print your information off so I can follow it. I was in Perth and Fremantle in 1982& 1983 I loved those cities. I was a Marine on a Navy ship. I met a young lady and wanted to stay but my Gunny wouldn't let me. I did have a friend that met a lady and went back after the Marine Corps. Australia is a beautiful country. Thanks!
Mr 007, you seem to think the relays are working on this machine. Sense the none of the idiot lights work on this machine including the alt light. do you think if I put a light in this system the alternator would start charging? Thanks
hello ChiefCWA, Yes perth is ok but most people in Aus live on the eastern coast. Not quite sure what you mean in your last post, i assume you meant not much of your instrument lights work any more. In a normal motor car the alternator light is critical and is used to excite the alternator when you start the engine. But your machine has two items to get your alternator away being the dash alternator warning light and a small resistor at the alternator wired to the output terminal. This is assuming yours is the same as the posted wiring diagram, and the non genuine alternator has been wired correctly. So yes to your question the non genuine alt prob has not got a resistor on it so you need the light to get the alternator started. Cheers
Ya your right none of the lights on the dash work. I have never taken the dash apart it might just need a light bulb to make the alternator work. That would be good. Someone said this is a latch system. I don't understand how to make the system unlatch when you kill the engine and turn the key off. Thanks for your help.
Mr 007, How is everything down under? I have taken the relay apart and cleaned the contacts. It seemed to help but the relay still sticks sometimes. If I turn the key from off to start and back several times it will start. So sometimes the relay works right and sometimes it don't would you have an idea what to check next? I took the dash apart and none of the lights worked but the glow plugs light and the fuel Gage. The bulbs screw into the printed board. But I couldn't get the dash completely apart so I couldn't check for voltage. Their for I couldn't check why the batt light was not working. Could you help.
Yes it is a latch system and it unlatches when the engine stops. What relay did you pull apart, the starter safety relay?? What do you mean it sticks some times, means nothing to me without knowing what relay you are talking about and how you are testing it. You have to be more technical with your approach and use a bulb or multi meter to test things or you will get no where. The symptom of intermittent starting that you are describing is commonly worn out brushes in your starter motor. That can be tested by bridging out the terminals at the starter to bypass all other wiring. And if the starter is engaging intermittently its a starter problem. The key has to be on for the battery relay to be enabled when testing. If your wiring and dash is in a mess you can put a bulb or resister directly on the back of the alternator if you just want to get it charging. Cheers
This is a Diesel engine so when I cut fuel to the engine and the engine stops the alt stops then the relay unlatches is that correct? I took apart the largest of the three relays inside the access door that opens to the radiator. It was the one that clicked when the key was turned on. It has a large cable from the batt and I thank the other goes to the starter. I thought the contacts stuck together because the contacts are made of copper and there was burnt places on them. I used sand paper to clean the black spots on the flat copper pieces that the cables are attached to. Then I cleaned the flat round copper piece that carries current from one cable to the other. The dash didn't look like anyone had ever been in it. I didn't have my meter with me the day I was there. When I go back to the machine I guess I need to take my multi meter and check voltage at the switch and alternator. The starter brushes could be bad but I don't thank so. I will check them when I go back to the machine. I like the idea of putting a resister on the back of the alt to make it charge. What size would I need and would I get my current straight from the batt? Thanks
Yes you are correct but left out a bit of detail. There are three relays there if your machine matches the schematic. There is the starter safety relay, load damp relay and the battery relay. You pulled to pieces the battery relay which is energized at first by turning on the key. When the engine starts the load damp relay senses that the alternator is operating and keeps the battery relay energized until the engine stops. So assuming you have done a good job of cleaning the contacts in that battery relay and it is working correctly then the only causes of your intermittent starter would be loose wiring, ignition switch, faulty starter safety relay, or faulty starter. You can use a resister to excite your alternator, you can use a 200ohm 5watt ceramic wired between the alternator output terminal and the warning light terminal. I would recommend you use a 24V aprox 2watt watt bulb wired in the same place. You can buy a small inline bulb holder from auto outlet or electronics store. Some people use mini festoon bulbs and they fit perfectly inside a inline fuse holder. It has to withstand the heat of the bulb so buy appropriate item. The bulb would give quick visual guide as to the operation of your relays and alternator. The bulb should be off with the engine off and ignition off. On with the ignition on and then go out when the engine starts. Keep in mind heat and vibration when your wiring at the back of your alt. Clamp your wires with some small cable tires and some tubing so they don't wear through. Cheers
Holy thread resurrection! I needed that ancient Hitachi wiring diagram that -3Doc posted in 2017. Now, I can fix my customer’s antique, dirty, greasy, hoe with confidence. Under the midnight sun, no less. I love this place and all you crusty bastages.