'05 Cat 305 CR electrical problem, no start, ignition dead

[hrc200x]

Started the excavator this morning to move it 50 feet out of the way, started fine, shut it off, about a hour later came back and tried to move it and when turning the key on it would beep, fuel needle moves, dash lights came on which is all normal but when I hit they key everything goes out and starter doesn't engage or make any noise. Tried key again and the same thing, kept trying the key, sometimes when key on the lights would come on, then others nothing at all when key is on. A couple times when the key in off position I could hear a buzzing coming from under the seat by the hour meter, turn key on and the buzz would quit, or when it was buzzing with key off it would quit on its own after 5 seconds or so. Now key in the on position is totally dead and in the off position there is no noises either.

I think this problem has been in the works for quite awhile now. As far back as a year I can remember needing to hold the key in the start position before the started would engage, it was very minimal though, like a second rather than instantly. Or I would turn it on, dash lights and everything would come on but try to start it and all would go out, it only did this a handful of times.

As far as a buzzing next to hour meter there is a small box there with wires going into it that says NGK on it.

Also I've test lighted fuses in the panel and there is power that far, but when am holding the test light on a fuse and its lit up and hit the horn or the ignition the light goes dim.

I've got some ideas, such as bad ignition or grounds, but what do you think? Is there any wiring diagrams available? Thanks in advance.

 

[Nige]

Sounds to me like the first place you should look is the battery ground cable, after that the engine ground cable, plus the ground cables that run to and from the master switch. After that all the "Hot" positive cables between the battery and the starter motor.
If that doesn't fix it the battery would be the next stop. Do you have a voltage tester..? If so put it across the battery terminals and watch the voltage while someone else tries to start it. It will probably fall like a stone.

For a wiring schematic PM me with your Serial Number and your e-mail address. There's a schematic here with your name on it ............

 

[Delmer]

Do you have a voltage tester..? If so put it across the battery terminals and watch the voltage while someone else tries to start it. It will probably fall like a stone.

And if the battery voltage doesn't stay down in the start position, then go back to the cable connections. Either use your voltmeter to work your way to the starter one connection at a time until you find the voltage drop, or hold it in start and tap the connections until you find the one that makes it start.

 

[hrc200x]

Thanks for the help. First thing I did was hook a jumper pack to the battery and tried the key and lights came on, took the battery cables off and put them on again and its started the rest of the day. Never would i have thought since power was getting to the fuse panel that it still would have been a bad connection at the battery. Didn't know that just a little power could get through letting some things work and others not, that and how it seems like its been a upcoming problem for the last year figured something bigger was wrong.

 

[Nige]

Battery terminals work loose over time caused by the heating & cooling of the terminals. That's why one of the items on the regular maintenance checklist say "disconnect the battery cables and clean the terminals on the battery and cables. Refit the cables and tighten the connections". No criticism intended but I wonder when you last did that...?

 

[hrc200x]

Every year the battery is taken out for the winter and put on a charge once a month, put back in spring. After looking at it I think the main problem is the positive clamp seems like it bottoms out on its self before it tightens real well on the lug of the battery.

 

[Nige]

Every year the battery is taken out for the winter and put on a charge once a month, put back in spring. After looking at it I think the main problem is the positive clamp seems like it bottoms out on its self before it tightens real well on the lug of the battery.

Is the battery post or maybe the inside of the terminal worn a bit..? The cable terminals shouldn't even bottom out on to the battery if everything is OK.

Is there any chance the battery has been replaced at some time with one with slightly smaller post size..?

 

[lantraxco]

I have had good luck removing the clamp bolt and with a hacksaw cutting away some lead from the area were the two halves meet when the bolt is tightened. There are also, if still available, lead shims you could wrap the post with and then install the clamp over.....

 

[hrc200x]

Is the battery post or maybe the inside of the terminal worn a bit..? The cable terminals shouldn't even bottom out on to the battery if everything is OK.

Is there any chance the battery has been replaced at some time with one with slightly smaller post size..?

Possibly, it is a NAPA battery. Good tip with the hacksaw. Currently everything seems fine, and if I recall the old saying is if its working don't mess with it. Or does it go if its working mess with it till it doesn't.

 

[Cat 304 CCR]

Thanks for the post. I have had the identical problem with an 07 304 Cat. It has had intermittent start problem. I have replaced a start relay and the ignition switch. I even changed the battery to no avail. No help with the problem. That is my next step, cut off battery clamps and put on new ones. If that does not work, I will go through changing relays I have found on my schematic. This problem has got to get fixed. Will let you all know if this does the trick or further trouble shooting is required.

 

[hrc200x]

I had power at the fuse panel even when the connection at the battery was bad. When the key was turned on it wasn't enough power to illuminate the dash lights or make the buzzer sound.

Have you tried jumping it with a vehicle or jump start pack when the problem is happening?

Our machines are set up differently but mine has two circuit breakers I think they are behind where the battery mounts, they are round buttons that say 60 on them.

Is there any rhyme or reason to when your issue occurs? After it sits awhile, hot/cold temperature, after rain, etc.

Possible bad safety switch in the fold down lever that engages the hydraulics. Lever in the 305cr needs to be disengaged before it will start.

 

[Nige]

One thing may be worth pointing out in response to both posters. If the terminations on your battery cables are not obviously eaten away by corrosion they are probably OK. If the battery is an aftermarket one (NAPA in the case of hrc200x) it could have JIS instead of SAE posts on it. JIS posts are a hair smaller than SAE (but indistinguishable to the naked eye) and therefore the terminal will have to close up more before it tightens on the post. So my advice if the terminal connections are not obviously eaten away is look at the battery rather than the cables.

If you do replace terminals then they need to be correctly crimped or soft soldered to the cables otherwise you will create more problems than you solve. DO NOT under any circumstances use the "quick replacement" battery terminals that clamp to the cables with a couple of bolts.

 

[rossaroni]

I ran into similar problems with an 1840 that I have. The positive post was worn to the point that it would not charge. They do make thin lead caps that fit over top of the existing battery posts to give just a little bit more clamping power. If I recall correctly, they were about $2 for a set of them. Still on there today, 2 years later.

 

[David Wolinsky]

Had same problem with 2000 303.5. tried all the suggestions given here (thanks to all by the way). Replaced both the starter disable relay and starter relay as they were cheap and easy. Still same no start problem, was intermittent and then finally no go. Tested the starter relay connection that comes from the disable relay using a meter and got 8 or so volts using the ground on the connector. Ran a jumper wire to the battery ground direct and tested 12.4 volts. That let me know I had a partially compromised ground at the relay connector. Rather than try to figure out where the ground wire was faulty I cut the ground wire on the side before the starter relay and hooked it to my neg battery jumper and she fired right over. I pulled the bolt holding the relay in place and grounded it there. Been starting right up ever since.